NERVOUS SYSTEM DISEASE
Ed Friedlander, M.D., Pathologist
scalpel_blade@yahoo.com

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Welcome to Ed's Pathology Notes, placed here originally for the convenience of medical students at my school. You need to check the accuracy of any information, from any source, against other credible sources. I cannot diagnose or treat over the web, I cannot comment on the health care you have already received, and these notes cannot substitute for your own doctor's care. I am good at helping people find resources and answers. If you need me, send me an E-mail at scalpel_blade@yahoo.com Your confidentiality is completely respected. No texting or chat messages, please. Ordinary e-mails are welcome.

DoctorGeorge.com is a larger, full-time service. There is also a fee site at www.afraidtoask.com.


If you have a Second Life account, please visit my teammates and me at the Medical Examiner's office.

Freely have you received, give freely With one of four large boxes of "Pathguy" replies.

I'm still doing my best to answer everybody. Sometimes I get backlogged, sometimes my E-mail crashes, and sometimes my literature search software crashes. If you've not heard from me in a week, post me again. I send my most challenging questions to the medical student pathology interest group, minus the name, but with your E-mail where you can receive a reply.

Numbers in {curly braces} are from the magnificent Slice of Life videodisk. No medical student should be without access to this wonderful resource.

I am presently adding clickable links to images in these notes. Let me know about good online sources in addition to these:

Freely have you received, freely give. -- Matthew 10:8. My site receives an enormous amount of traffic, and I'm still handling dozens of requests for information weekly, all as a public service.

Pathology's modern founder, Rudolf Virchow M.D., left a legacy of realism and social conscience for the discipline. I am a mainstream Christian, a man of science, and a proponent of common sense and common kindness. I am an outspoken enemy of all the make-believe and bunk that interfere with peoples' health, reasonable freedom, and happiness. I talk and write straight, and without apology.

Throughout these notes, I am speaking only for myself, and not for any employer, organization, or associate.

Special thanks to my friend and colleague, Charles Wheeler M.D., pathologist and former Kansas City mayor. Thanks also to the real Patch Adams M.D., who wrote me encouragement when we were both beginning our unusual medical careers.

If you're a private individual who's enjoyed this site, and want to say, "Thank you, Ed!", then what I'd like best is a contribution to the Episcopalian home for abandoned, neglected, and abused kids in Nevada:

I've spent time there and they are good. Write "Thanks Ed" on your check.

Help me help others

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Especially if you're looking for information on a disease with a name that you know, here are a couple of great places for you to go right now and use Medline, which will allow you to find every relevant current scientific publication. You owe it to yourself to learn to use this invaluable internet resource. Not only will you find some information immediately, but you'll have references to journal articles that you can obtain by interlibrary loan, plus the names of the world's foremost experts and their institutions.

Alternative (complementary) medicine has made real progress since my generally-unfavorable 1983 review. If you are interested in complementary medicine, then I would urge you to visit my new Alternative Medicine page. If you are looking for something on complementary medicine, please go first to the American Association of Naturopathic Physicians. And for your enjoyment... here are some of my old pathology exams for medical school undergraduates.

I cannot examine every claim that my correspondents share with me. Sometimes the independent thinkers prove to be correct, and paradigms shift as a result. You also know that extraordinary claims require extraordinary evidence. When a discovery proves to square with the observable world, scientists make reputations by confirming it, and corporations are soon making profits from it. When a decades-old claim by a "persecuted genius" finds no acceptance from mainstream science, it probably failed some basic experimental tests designed to eliminate self-deception. If you ask me about something like this, I will simply invite you to do some tests yourself, perhaps as a high-school science project. Who knows? Perhaps it'll be you who makes the next great discovery!

Our world is full of people who have found peace, fulfillment, and friendship by suspending their own reasoning and simply accepting a single authority that seems wise and good. I've learned that they leave the movements when, and only when, they discover they have been maliciously deceived. In the meantime, nothing that I can say or do will convince such people that I am a decent human being. I no longer answer my crank mail.

This site is my hobby, and I do not accept donations, though I appreciate those who have offered to help.

During the fifteen years my site has been online, it's proved to be one of the most popular of all internet sites for undergraduate physician and allied-health education. It is so well-known that I'm not worried about borrowers. I never refuse requests from colleagues for permission to adapt or duplicate it for their own courses... and many do. So, fellow-teachers, help yourselves. Don't sell it for a profit, don't use it for a bad purpose, and at some time in your course, mention me as author and KCUMB as my institution. Drop me a note about your successes. And special thanks to everyone who's helped and encouraged me, and especially the people at KCUMB for making it possible, and my teaching assistants over the years.

Whatever you're looking for on the web, I hope you find it, here or elsewhere. Health and friendship!

BIBLIOGRAPHY / FURTHER READING

PicoSearch
  Help

More of Ed's Notes: Ed's Medical Terminology Page

Perspectives on Disease
Cell Injury and Death
Accumulations and Deposits
Inflammation
Fluids
Genes
What is Cancer?
Cancer: Causes and Effects
Immune Injury
Autoimmunity
Other Immune
HIV infections
The Anti-Immunization Activists
Infancy and Childhood
Aging
Infections
Nutrition
Environmental Lung Disease
Violence, Accidents, Poisoning
Heart
Vessels
Respiratory
Red Cells
White Cells
Coagulation
Oral Cavity
GI Tract
Liver
Pancreas (including Diabetes)
Kidney
Bladder
Men
Women
Breast
Pituitary
Thyroid
Adrenal and Thymus
Bones
Joints
Muscles
Skin
Nervous System
Eye
Ear
Autopsy
Lab Profiling
Blood Component Therapy
Serum Proteins
Renal Function Tests
Adrenal Testing
Arthritis Labs
Glucose Testing
Liver Testing
Porphyria
Urinalysis
Spinal Fluid
Lab Problem
Quackery
Alternative Medicine (current)
Preventing "F"'s: For Teachers!
Medical Dictionary

Courtesy of CancerWEB

Niels Bohr

Niels Bohr
The opposite of a correct statement is a
false statement. But the opposite of a profound
truth may well be another profound truth.

QUIZBANK -- Nervous system (all)

    Patterns of Nervous System Disease: 1, 20-21, 28-68, 385-386
    Stroke and Hemorrhage: 2-19, 22-27, 69-85, 162-230, 311-312
    CNS Infections: 85-161, 289
    Neurodegenerative disease: 232, 234-242, 244-248, 250-254, 256, 258, 262-266, 273, 276-282, 284-286, 291-294, 297-300, 302-304
    Demyelinating Disease, Poisons: 231, 233, 243, 249, 255, 257, 259-261, 267-272, 274-275, 283, 287, 290, 295-296, 301, 305-310, 313-333, 387
    Tumors: 334-384

INTRODUCTION

No one is born wise.

          -- Ptahhotpe, c. 2350 B.C.

I do not understand my own behavior.

          -- Paul of Tarsus, Romans 7

Be not angry that you cannot make others as you wish them to be, since you cannot make yourself as you wish to be.

          -- Thomas of Kempis

"It must be inconvenient to be made of flesh," said the Scarecrow, thoughtfully, "for you must sleep, and eat and drink. However, you have brains, and it is worth a lot of bother to be able to think properly."

          -- Scarecrow, The Wizard of Oz

How many psychiatrists does it take to change a light bulb?
Only one, but it takes a long time, and the light bulb has to WANT to change.

          -- Anonymous

A good person can be stupid and still be good. But a bad person must have brains.

          -- Maxim Gorky

Ah, it is the fault of our science that it wants to explain all, and if it explain not, then it says there is nothing to explain.

          -- Dr. Abraham Van Helsing (pathologist), Dracula (Bram Stoker)

I'd rather have a free bottle in front of me than a prefrontal lobotomy.

          -- Anonymous

For botulism, click here.
For tetanus, click here.

* Autopsy on brain and muscle: Arch. Path. Lab. Med. 119: 777, 1995.

* Jung accused Freud of "regarding the brain an appendage of the sexual organs." Be this as it may, our brains are what tells us "happy" or "not happy". Some people report themselves to be happier than others, and this tends to stay constant over time. Contrary to what you've been told (by "liberals" or "conservatives"), there's little-or-no correlation with age, race, economic class, or educational level. There's a strong correlation between being happy and (1) being basically in control of your own destiny; (2) being physically healthy; (3) being happily married; (4) living in a country where there's opportunity. See Sci. Am. 274(5): 79, May 1996.

Neuropathology Blog
By a cyberfriend of mine
For those with a special interest

Brain, Nerve, Muscle
Photo Library of Pathology
U. of Tokushima

CNS
Taiwanese pathology site
Good place to go to practice

Neuropathology
Surgical Pathology Atlas
Nice photos, hard-core

Neuropathology I
Path photos with labels
Ohio State

Neuropathology II
Path photos with labels
Ohio State

Neuropathology
Massive collection
In Portuguese

Neuropathology
Student online study with commentary
Rochester

Nervous System
Iowa Virtual Microscopy
Have fun

Neuropathology
Brown Digital Pathology
Some nice cases

"Why I Support Amateur Boxing"
Position paper by Ed
This is something about which
reasonable people can differ.

CNS
Photos, explanations, and quiz
Indiana U.

Neuropathology
Student online study with commentary
Northeastern Ohio U. COM

Neuroradiology
Radiology-Pathology
Uniformed Services

Tulane Pathology Course
Great for this unit
Exact links are always changing

Inflammatory and Demyelinating Diseases
Great pictures in a clickable
handout, from Duke

Brain Exhibit
Virtual Pathology Museum
University of Connecticut

Neuropathology
Great pathology images
Indiana Med School

Nancy Peress MD
Neuropathology
Good introduction

Dr. Fung
Oklahoma
Great stuff -- For advanced learners

Dr. Fung
Neuropathologyweb.org
Good easy introduction
Dimitri Agamanolis MD; thank you!

NEUROPATHOLOGY UNIT: LEARNING OBJECTIVES

HOW IS NEUROPATHOLOGY DIFFERENT?

BRAIN DEVELOPMENT AND ITS PROBLEMS

Week 3-4: The neural tube forms and fuses

{10331} anencephalic
{39138} anencephalic
{39140} omphalocele; child also had anencephaly

Anencephalic child

WebPath Photo

Anencephalic child

WebPath Photo

Meningoencephalocele
Spectacular x-ray
Brazilian Medical Students

Anencephalic child
Poorly formed brain
WebPath Photo

Anencephaly
WebPath Photo

Anencephaly
WebPath Photo

Anencephaly
WebPath Photo

Rachischisis
WebPath Photo

Encephalocele
WebPath Photo

Encephalocele with exencephaly
WebPath Photo

{53752} encephalocele
{15843} encephalocele in amniotic band syndrome
{13397} encephalocele

{05224} myelocele
{12424} myelocele
{13396} myelocele
{13398} myelocele

Open neural tube defect

KU Collection

Lipomyelomeningocele
Pittsburgh Pathology Cases

Meningomyelocele

WebPath Photo

Meningomyelocele
WebPath Photo

Iniencephaly
WebPath Photo

Weeks 5-6: The rostral CNS cleaves into two hemispheres

{10333} holoprosencephaly
{10336} holoprosencephaly
{25614} cyclops

Holoprosencephaly

WebPath Photo

Holoprosencephaly

WebPath Photo

Holoprosencephaly

WebPath Photo

Holoprosencephaly

WebPath Photo

Holoprosencephaly
WebPath Photo

Holoprosencephaly
WebPath Photo

Holoprosencephaly
WebPath Photo

Weeks 6-14: Neurons migrate to their proper positions

{32949} polymicrogyria, gross
{00141} polymicrogyria, gross
{01246} polymicrogyria, patient (severe disability)

Weeks 15-16: The brain is further modelled

{32139} porencephaly

{32943} encephaloclastic porencephaly

After six months: The brain is already formed and the gyri are largely modelled, but it can still be damaged (typically by ischemia, viruses, or some serious metabolic process).

    HYDRANENCEPHALY: Replacement of the cerebral hemispheres by large cysts made of leptomeninges and glia. There is no ependyma.

      This results from ischemia / hypoxia or infection (i.e., TORCH). It may be diffuse or localized.

{10339} hydranencephaly (this happens to have been a case of toxoplasmosis)
{53696} hydranencephaly patient

Hydranencephaly

WebPath Photo

Hydranencephaly
WebPath Photo

Tough to place:

{32996} Arnold-Chiari (there is also pus in the ventricles)
{17683} Arnold-Chiari, long cerebellar tonsils

{05236} Dandy Walker, no roof on vermis
{15466} Dandy Walker, no roof
{16600} Dandy Walker
{39058} Dandy Walker, thin roof

{27928} tuberous sclerosis, face; adenoma sebaceum
{27948} tuberous sclerosis, brain; note the white tubers
{01828} tuberous sclerosis, brain; the tubers appear as whiter areas of cortex
{01830} tuberous sclerosis, brain

Tuberous sclerosis

WebPath Photo

Tuberous sclerosis

WebPath Photo

Tuberous sclerosis

WebPath Photo

{09022} syringomyelia; myelin stain; the tracts have been damaged by the syrinx above and below

{15678} colloid cyst, foramen of Munro

{01251} arachnoid cyst
{01252} arachnoid cyst
{01253} arachnoid cyst

{33069} cerebral palsy from birth hypoxia
{18763} kernicterus
{31972} kernicterus
{31989} kernicterus
{53734} kernicterus after-effects (small head)

Kernicterus
Brazil Pathology Cases
In Portuguese

Kernicterus
WebPath Photo

CELLULAR REACTIONS IN THE NERVOUS SYSTEM

Brain Cells I
From Chile
In Spanish

Brain Cells II
From Chile
In Spanish

Brain Cells III
From Chile
In Spanish

Histopathology of the brain
Several nice photos
Harvard

    NEURONS are the principal units of nervous system circuitry, and the central characters in neuropathology.

{01278} red neurons
{01279} red neurons
{31969} red neurons (Purkinje cells are dead)

Red neurons

WebPath Photo

Red neurons

WebPath Photo

{01288} neurofibrillary tangles; the stringy stuff in the neuron is stained poorly here
{01291} neurofibrillary tangles; the black, stringy stuff in the neurons

Neurofibrillary tangles

WebPath Photo

{01330} Lewy body

Lewy body
Tom Demark's Site

{01311} Pick body (the large black thing)

{01303} Hirano body (you need EM to appreciate the corduroy effect)

{01293} Granulovacuolar degeneration

{01314} Lafora body (PAS stain, "red sunflower")


{01337} Negri bodies in Purkinje cells
{01738} Negri body, sketch

Rabies

Yutaka Tsutsumi MD

Rabies
Negri body in a neuron
KU Collection

Rabies
Negri bodies
Wikimedia Commons

{01272} neuromelanin

        LIPOFUSCIN is common in older people (* "simple pigmentary atrophy").

{01270} lipofuscin; oil red O stain

Intraneuronal storage
Tay-Sachs
WebPath Photo

Sphingolipidosis
Brazil Pathology Cases
In Portuguese

        INTRA-NEURONAL STORAGE is characteristic of certain inborn errors of metabolism (listed below). The cytoplasm is distended, and the nucleus typically appears displaced.

        * FERRUGINATION is hemosiderin-encrustation of neurons near sites of past hemorrhage.

      AXONAL REACTION is also known as CENTRAL CHROMATOLYSIS. If an axon is severed or otherwise injured, the perikaryon (neuronal cell body) swells, rounds up and becomes pale-staining. The Nissl substance disappears except just below the cell membrane, and the nucleus moves to the edge of the cell.

      * "Peripheral chromatolysis": The neuron is recovering!

      * Healthy Clarke's column and some other neuron groups can show central chromatolysis for some reason.

{01275} axonal reaction, central chromatolysis; you can just see the RER as purple at the rims of the affected neurons
{01276} axonal reaction, central chromatolysis

      AXONAL DEGENERATION is said to occur when a neuron cannot maintain the axon to which it is attached.

        WALLERIAN DEGENERATION is the changes in an axon severed from its cell body.

{09602} Wallerian degeneration; corticospinal tract is lost from a stroke higher up
{09591} Wallerian degeneration, corticospinal tract is lost from a stroke higher up (myelin stain)

Wallerian degeneration

WebPath Photo

      AXONAL SPHEROIDS are spherical or sausage-shaped knobs when axons have been damaged by mechanical trauma ("diffuse axonal injury", the main lesion), ischemia, radiation (famous), or in axonal diseases.

      * Clinicians please note: The term "Betz cells", used as a synonym for cortical neurons ("You have two Betz cells held together by an ethanol molecule / spirochete"), should be limited to the large cortical neurons that supply axons to the descending pathways.

    ASTROCYTES show on H&E only as relatively large glial nuclei in the neuropil.

      You remember that PROTOPLASMIC ASTROCYTES occur mostly in gray matter, FIBROUS ASTROCYTES occur mostly in white matter, and that their "foot processes" / "end plates" have to do with the blood-brain barrier.

      The intermediate filaments in astrocytes are vimentin and GLIAL FIBRILLARY ACID PROTEIN (GFAP, a specific marker).

      GLIOSIS is hypertrophy and proliferation of astrocytes at sites of injury, the counterpart of "scarring" elsewhere in the body.

        Instead of laying down collagen or other extracellular material, the astrocyte cytoplasm itself becomes the "scar". There is still some "scar contraction" though not so much as in collagenous scar.

{01366} gliosis, special glial stain
{01368} gliosis, special glial stain

Glial scar, outer cortical surface5
Gunshot wound
KCUMB Team

          The only fibroblasts in the CNS are in the blood vessels, and these typically only contribute to healing when a hematoma must be organized or an abscess walled off.

            * The clever pathologist distinguishes the wall of an abscess from a glioblastoma by observing that fibroblasts do not stain with GFAP, while spindle cell astrocytes do.

        Gliotic scars, especially after penetrating injury, are considered to give rise to many cases of epilepsy.

        GEMISTOCYTES are astrocytes seen in reactive processes. They are large, pink cells.

{01357} gemistocytes
{01360} gemistocytes

        FIBRILLARY ASTROCYTES (not to be confused with fibrous astrocytes, a normal cell) result when gemistocytes settle downward lose most of their cytoplasm, though not the complexity of their processes.

        ANISOMORPHIC GLIOSIS is a proliferation of neoplastic, slightly-atypical protoplasmic astrocytes, the lowest-grade of astrocytoma.

      ROSENTHAL FIBERS are pink-staining structures within the processes of large astrocytes. They are shaped like slightly-crumpled hot-dogs. You can see them at any site of gliosis, and they help make the diagnosis of certain astrocytomas.

        * Future neuropathologists: the fibers are made up mostly of a crystallin plus GFAP.

{01390} Rosenthal fibers
{01393} Rosenthal fibers in * Alexander's disease (mutant GFAP; worked out Nat. Genet. 27: 117, 2001)

      * CORPORA AMYLACEA ("polyglucosan bodies"; "fool's cryptococcus") are 10-50 spherical masses of polysaccharide within astrocyte end-processes. They become common as the brain ages; look for them in the subependymal and perivascular regions.

        The thankfully-rare "adult polyglucosan disease" features many of these in the brain and heart. The mutation is in the glycogen brancher enzyme (Muscle & Nerve 32: 672, 2005; Neurology 61: 263, 2003).

      ALZHEIMER'S TYPE I GLIA are monstrously enlarged astrocytes with huge, dark nuclei. You seen them in subacute sclerosing panencephalitis (SSPE) and progressive multifocal leukoencephalopathy.

      ALZHEIMER"S TYPE II GLIA are astrocytes with edematous-looking, swollen nuclei. They are seen in liver failure and other states with high blood ammonia (Reye's, urea cycle problems). Look in the gray matter.

        * Despite "Big Robbins", only in one rare disease does the pale, swollen nucleus contain glycogen.

{00539} Alzheimer's type II glia (two of them)
{01383} Alzheimer's type II glia (one in the center)

        NOTE: Neither type of "Alzheimer's glia" has anything to do with Alzheimer's disease.

      * DECREASED NUMBERS OF ASTROCYTES is a maker for longstanding mild ischemia.

    OLIGODENDROGLIA have small, lymphocyte-like nuclei with a halo (* formalin artifact).

      They are primarily responsible for making myelin; unlike the Schwann cell, one oligodendrocyte can wrap several axons. In the white matter, they are easy to spot. In the gray matter, look for them around neurons ("satellite cells").

      Diseases of oligodendroglia affect myelin. LEUKODYSTROPHIES affect all myelin, and are usually hereditary. DEMYELINATING DISEASES produce patchy myelin loss. You remember that PERIVENTRICULAR LEUKOMALACIA, the usual lesion in cerebral palsy, features loss of oligodendroglia around the ventricles. SCLEROSIS in CNS means loss of myelin and its replacement by astrocytes.

      Morphologically, the reactions of oligodendroglia are usually limited to dying and disappearing. Herpes and JC viruses produce typical inclusions in oligodendroglia; chronic measles (SSPE) may do so as well.

      Cytoplasmic inclusions in the oligodendroglia (* Papp-Lanton inclusions) are masses of scrambled microtubules, specific for the multiple systems atrophy family (Shy-Drager, striatonigral degeneration, some cases of olivopontocerebellar degeneration). See Am. J. Path. 155: 1241, 1999. They are composed of synuclein, alphaB-crystallin, and ubiquitin. You won't see Lewy bodies.

    EPENDYMA seldom show much reaction, either. If ependymal cells die, gliosis between the cells produces EPENDYMAL GRANULATIONS.

    MICROGLIA is an ancient misnomer for macrophages in the brain. (* Philologists: Astrocytes and oligodendroglia are "macroglia".)

      ROD CELLS are reactive macrophages with elongated nuclei. They are described in Rocky Mountain spotted fever, typhus, syphilis, and various viral infections. I suspect the nuclei are elongated because the macrophages are wandering through the neuropil; this can't be good for connections.

      GITTER CELLS are actively phagocytizing macrophages in the CNS). They are typically "gitting" rid of dead myelin and other cell debris.

      MICROGLIAL NODULES are clusters of macrophages around damaged tissue. Think of viral or rickettsial disease. (Don't expect to see good granulomas in diseases unique to the CNS.) You may actually see the macrophages eating neurons (NEURONOPHAGIA, naturally).

      HIV GIANT CELLS are the familiar Langhans / foreign body type resulting from macrophages that fuse in HIV infection. They notice the HIV gp120 on each other's surfaces, and try to engulf each other.

Neuropathology of HIV infection
Nice photos and article
Temple U.

{01461} neuronophagia

Neuronophagia

WebPath Photo

    * Despite old teachings, there are always a few T-cells on patrol in the brain, and even finding a group of B-cells doesn't necessarily mean disease (Brain 126: 1058, 2003).

    Worth noting: Neurons are very sensitive to ischemia (worst) and hypoxia (somewhat better tolerated as long as there's blood flow, but still not good). Oligodendroglia are less sensitive than are neurons. Ependymal cells are even less sensitive, while astrocytes are the least sensitive, capable of withstanding all but the most severe and prolonged hypoxia.

INCREASED INTRACRANIAL PRESSURE / HERNIATION

Edema and Herniation
From Chile
In Spanish

Brain Herniation
Radiology-Pathology
Uniformed Services

    Increased intracranial pressure is said to be present when recumbent CSF pressure exceeds 200 mm water.

      You know it's best to be cautious doing a lumbar puncture if there's a known or possible mass lesion in the cranial cavity -- the brainstem can hernia, causing instant death. If you do perform a lumbar puncture, you will measure the CSF pressure using the manometer during the procedure.

      When brain volume (localized or generalized) increases for any reason (edema, trauma, hemorrhage, tumor, inflammation, abscess, echinococcus, gumma, etc.), some blood is first pushed out of the skull by venous compression, but this is minuscule. Any additional increase in brain volume will increase intracranial pressure. Some CSF will be lost, and then the brain itself will be forced to move within the skull.

      Increased intracranial pressure first presents as headache, mental dullness, and nausea and vomiting (the latter are important and are curiously omitted from "Big Robbins"). Clinicians of course look for papilledema, pushing of the optic nerve forward into the eyeball.

    The skull and even dural membranes are not going to budge for the expanding brain. Instead, HERNIATION will occur when brain volume is sufficiently increased. (The brain is being squeezed through openings and around corners like toothpaste.)

      CINGULATE HERNIATION (SUBFALCINE HERNIATION) results when one cingulate gyrus is pushed underneath the falx. Occlusion of the callosal-marginal branch of the anterior cerebral artery can result.

{01465} cingulate herniation, view from above with falx removed

        *Future angiographers: Detect these by finding displacement of the pericallosal arteries!

      UNCAL HERNIATION (TRANS-TENTORIAL HERNIATION, HIPPOCAMPAL HERNIATION) results when the medial temporal lobe is pushed between the cerebral peduncles and the tentorium cerebelli.

{01471} tentorial herniation marks
{31975} Herniation marks
{01473} tentorial herniation marks
{01482} tentorial herniation marks
{00524} tentorial herniation, crushed cerebral peduncle
{00542} tentorial herniation, crushed cerebral peduncle

Brain that has herniated

WebPath Photo

Uncal herniation

WebPath Photo

        Stretching of the third cranial nerve produces the famous "fixed dilated pupil" on the IPSILATERAL side.

          Beware: compression of the contralateral cerebral peduncle against the opposite tentorium -- Kernohan's notch ("crus syndrome") -- will produce "fixed dilated pupil" on the CONTRALATERAL side.

        Crushing of the posterior cerebral artery against the edge of the tentorium results in occlusion, and explains the cortical blindness (if unilateral, "homonymous hemianopsia") that often follows head injury.

{01483} crushed posterior cerebral artery

        Crushing of the cerebral peduncle on the same side as the expanding lesion causes hemiparesis on the opposite side of the body.

        * You may also note paralysis of upward gaze (injury to the tectum) or sudden increase in intracranial pressure (crushing shut of the aqueduct of Sylvius), and so forth.

        * Expanding lesions in the posterior fossa can give REVERSE TENTORIAL HERNIATION. This causes many of the signs above, and the tension on the fifth cranial nerves is painful.

{01477} reverse tentorial herniation marks

      TONSILLAR HERNIATION (CEREBELLAR HERNIATION, BRAINSTEM HERNIATION, CONING) results from herniation of the cerebellar tonsils out through the foramen magnum, compressing the medulla. The latter is the mechanism of death in most cases of brain swelling.

{01474} tonsillar herniation damage
{01476} tonsillar herniation damage

Tonsillar herniation
"Coning"
WebPath Photo

        As the brainstem is pushed caudally, the penetrating vessels are affected, resulting in the centrally-located DÛRET HEMORRHAGES ("Duret hemorrhages", "secondary brainstem hemorrhages", "slit hemorrhages") in the pons and midbrain. This is bad, and can leave a survivor locked-in.

{01485} Dûret hemorrhage

Duret hemorrhages

WebPath Photo

Duret hemorrhage

WebPath Photo

        * "Big Robbins" states the vessels are avulsed, causing hemorrhage. Or maybe they are occluded by stretching, and then the ischemic regions become hemorrhagic when re-perfused during heroic resuscitation attempts.

      TRANS-CALVARIAL HERNIATION is said to be present when brain herniates out through an open fracture in the skull.

{01479} trans-calvarial herniation after-effect

    Certain drugs, notably some of the tetracyclines, and overdoing vitamin A, can increase intracranial pressure, or it can be idiopathic ("pseudotumor cerebri"; IDIOPATHIC INTRACRANIAL HYPERTENSION).

      Many patients with the idiopathic illness are overweight, and the effect is perhaps due to the extra physical weight on the right atrium and thus to the dural sinuses (J. Neurosurg. 101: 878, 2004).

      Other causes of increased central venous pressure (cardiac septal defects, congestive heart failure, AV malformations) or obstruction to the venous outflow from the brain (i.e., little thrombi from hypercoagulable blood) also need to be considered.

      * You will learn on rotations about surgery (shunts, optic nerve fenestration) for this relatively common clinical problem.

CEREBRAL EDEMA

    Brain swelling is serious, since it leads to herniation (and maybe scrambles the neuropil, too.) Three types are classically listed.

      VASOGENIC EDEMA (the most common type) is fluid in the extracellular space. Either (1) the capillaries have been damaged and are leaking protein (infarcts, infection, contusions, and notoriously lead poisoning though no one knows how Pb damages the endothelium) or (2) new, leaky capillaries are forming in an abnormal area (abscess, primary or metastatic tumor).

        Grossly, the white matter will be soft and wet, and more affected than gray (since the intercellular space is larger in the white matter).

        Microscopically, in vasogenic edema there are little vacuoles throughout the white matter. Also look for expansion of the Virchow-Robin spaces. If longstanding, axons degenerate and myelin is lost.

        Note that this sort of edema will light up on enhanced scans (ask a neuro-radiologist about "ring enhancement" around tumors and abscesses.)

        * Acute mountain sickness features cerebral edema, which now appears to be due to the vessels in the white matter becoming leaky (JAMA 280: 1920, 1998; update Lancet 361: 1967, 2003). Is high-altitude mountain climbing itself a risk factor for permanent brain damage? First systematic survey indicates "Yes": Am. J. Med. 119: 168.e1, 2006.

{01464} edema after trauma

Edema from micrometastases

WebPath Photo

Cerebral edema
Wide gyri, obliterated sulci
WebPath Photo

{01344} vasogenic edema, note bubbles
{01345} vasogenic edema, note bubbles
{01438} vasogenic edema, note bubbles

        Worth remembering: Cerebral edema can kill a child or teen even after a blow that does not cause loss of consciousness. Team doctors began noticing this in the 1970's (JAMA 266: 2867, 1991). Especially, remember SECOND IMPACT SYNDROME, in which a second blow to the head sustained in a person who's recently had a concussion causes disastrous edema.

          His fans blame the aspirin he took for a headache and/or some paranormal martial-arts phenomenon. But Bruce Lee's death sounds like an example of this. He had been sparring during the day, and was found dead of massive, unexplained cerebral edema.
          Bruce Lee

          In the mouse model, the window of vulnerability for second-impact syndrome is 3-5 days (Neurosurg. 56: 364, 2005, photomicrographs). See below.

      CYTOTOXIC EDEMA means excessive intracellular water, indicating cells have been damaged. Look for this in ischemia, acidosis/hypercarbia, Reye's, acute massive liver failure (Am. J. Med. 96(1A): 3-S, 1994), and in water-overload, especially with low serum sodium/albumin.

        Grossly, the gray matter will be more affected, since that's where the business cells are.

        Microscopically, look for swelling and vacuolization of individual cells.

        As you would expect, cytotoxic and vasogenic edema often occur at the same time. In an infarct, for example, cytotoxic edema occurs early (as the neurons are dying), and vasogenic edema follows (as the endothelial cells are dying).

      INTERSTITIAL EDEMA ("transependymal edema") results from obstruction of the flow of spinal fluid ("non-communicating hydrocephalus"). CSF is forced across the ependyma, and the edema surrounds the ventricles.

    In edema of any kind, expect to see flattening of the gyri against the skull, and narrowing of the sulci.

HYDROCEPHALUS ("water-heads")

Hydrocephalus
From Chile
In Spanish

    You remember that CSF is produced by the choroid plexus within the ventricles, flows through the brain and out the foramina of Luschka and Magendie, and is resorbed at the arachnoid villi.

    NON-COMMUNICATING HYDROCEPHALUS results form blockage within the brain. These problems may be congenital (stenosis or malformation of the aqueduct of Sylvius, Dandy-Walker, Arnold-Chiari, fetal CMV) or acquired (tumors, meningitis with ventriculitis, large intracerebral bleeds or shifts compressing a foramen of Munro).

    COMMUNICATING HYDROCEPHALUS results from over-production of CSF (choroid plexus papilloma), obstruction in the subarachnoid space (i.e., after bacterial or tuberculous meningitis or subarachnoid hemorrhage) or problems with the arachnoid villi (i.e., dural sinus thrombosis).

{00191} hydrocephalic child

    HYDROCEPHALUS EX VACUO means nothing more nor less than brain atrophy from cell loss. There are fewer cells, and more room for fluid.

{32766} atrophy, attributed to alcoholism

Hydrocephalus ex vacuo

WebPath Photo

    Regardless of etiology, all forms of hydrocephalus produce enlarged ventricles.

      Before the sutures fuse (i.e., in young children), untreated hydrocephalus produces huge heads. Traction on the optic nerves forces downward gaze ("the setting sun sign"). Up to 1 child in 1000 is affected (Ped. Neurosurg. 32: 119, 2000); today, the disastrous outcome is preventable by spinal fluid shunting.

{00191} hydrocephalic child
{13394} hydrocephalus
{13395} hydrocephalus, transilluminated
{00194} hydrocephalic brain
{00197} hydrocephalic brain

      In adults, rapidly-progressive hydrocephalus produces rapidly increasing intracranial pressure. If the onset is more slow, patients merely suffer dementia.

      The entity "normal pressure hydrocephalus", with dementia, apraxia of gait, and urinary incontinence, is now known to be caused by a failure of the arachnoid granulations to keep up with the choroid plexus (Am. Fam. Phys. 70: 1071, 2004). It gets treated empirically with ventricular shunting, usually with good results.

      If increased intracranial pressure is severe, fluid will be forced through the ependyma ("interstitial edema"; see above).

    SUBDURAL HYGROMA results from CSF accumulating in a space where the arachnoid was somehow torn away from the dura. Among children, we're sorting out how much of this is due to child abuse and how much can have an innocent explanation (Ped. Neurosurg. 33: 188, 2000).

    Physicians: Please don't miss CSF LEAKS, following surgery or trauma. Fluid running out of the nose or ear is spinal fluid until proved otherwise. You can confirm your impression with a glucose reagent pad. (Remember that spinal fluid contains glucose, while snot does not.)

VASCULAR DISEASE OF THE NERVOUS SYSTEM

HYPOXIA, ISCHEMIA, AND INFARCTION

{09443} atherosclerosis of major arteries
{53786} perinatal hypoxia case

Cerebral Infarcts
From Chile
In Spanish

Pathology of stroke
Good photos
Wash U.

Multi-infarct dementia
WebPath Case of the Week

    You are already familiar with the various types of hypoxia ("anoxia"), and with the causes of hypoglycemia.

    The brain tolerates ischemia (low blood flow) very poorly, and much "brain damage from lack of oxygen" is probably due in large part to damage from low pH (i.e., when there is no blood to remove by-products of metabolism from the brain).

      You already know that incomplete infarction (i.e., a few minutes without blood flow) will be enough to kill neurons but will not liquefy the brain. The brain will remain solid if perfusion is restored within a few hours, since the glia will survive.

      Why the brain should be so vulnerable to poor perfusion is mysterious.

        Currently, there is also much interest in glutamate- and aspartate-based synapses getting stuck in the "on" position, allowing influx of calcium ("excitotoxicity"). This is getting to be a very popular idea, both in accounting for brain damage in poor perfusion and in diseases in which neurons "just disappear" (AIDS, ALS, several others; watch for drugs to prevent "excitotoxic damage"). Several are under investigation; no miracles yet. Still good reading: Science 268: 239, 1995.

      The reason for brain damage following hypoglycemia is even less-well understood. The morphology is the same as "hypoxic encephalopathy".

      Full necrosis (neurons and glia, liquid) of the brain following ischemic injury is called ENCEPHALOMALACIA (literally, "brain-softening"; remember that other things can make the brain soft).

{31968} widespread encephalomalacia, recent (purple cortex)

    ISCHEMIC / HYPOXIC ENCEPHALOPATHY is said to be present when the whole brain has suffered the effects of poor perfusion.

      In people with good arteries, there is no compromise of cerebral blood flow until systemic blood pressure drops below 50 mmHg. People with narrowed arteries (usually from atherosclerosis) can have brain damage following less severe drops in pressure.

      The clinicians are finally recognizing what the public has known for a long time: that cardiopulmonary bypass carries a real risk of subtle temporary or permanent brain damage ("pump head", Ann. Thorac. Surg. 59: 1296, 1312, 1336 & 1340, 1995).

      The morphology is generalized brain ischemia is familiar to general autopsy pathologists.

        By twelve hours after the insult, you'll probably be able to see "red neurons".

        The pyramidal cell layers of the cerebral cortex are much more severely affected than the other layers, so that milder degrees of ischemic produce LAMINAR NECROSIS. The most vulnerable area of cortex is probably the h1 segment of the hippocampus.

{00168} laminar necrosis; this is the slit running down the middle of the cortex, due to hypoxic damage long ago
{17731} laminar necrosis

        In hypoxia due to poor perfusion (i.e., in shock survivors), the obvious necrosis may even be limited to the WATERSHED ZONES ("BORDER ZONES") between the distributions of the major arteries. Look for necrosis adjacent to the sagittal sinus, curving laterally over the outer surfaces of the occipital lobes.

          There is another watershed zone in the lower thoracic spinal cord, so an episode of systemic hypoxia/shock may on occasion cause paraplegia.

{09604} watershed infarcts; you diagnose this by location
{09607} watershed infarcts

Watershed infarcts

WebPath Photo

          There is another border zone in the upper lumbar spinal cord, and paraplegia can follow a hypoxic episode.

      The degree of recovery of function depends on a number of variables. These include:

      • degree of hypoperfusion or hypoglycemia;
      • length of time elapsed prior to successful resuscitation;
      • patient age (kids do much better "because their nervous system is more plastic");
      • core body temperature (quality survival may be possible following prolonged cardiac arrest while freezing in the snow);
      • quality of the arteries (i.e., how much atherosclerosis, and are they normally formed?)

      Survivors may experience anything from transient confusion to persistent vegetative state or "brain death" ("apallic state").

        While the classic teaching is that the brain can withstand 3 minutes of poor perfusion "without damage", this assumes (wrongly) that a morphologically normal brain is a functionally normal brain.

        Anecdotally, "high-functioning" people have found themselves disabled after as little as 15 seconds of cardiac arrest; measurable brain damage follows most away-from-the-defibrillator cardiac arrests (Br. Med. J. 313: 143, 1996).

        Pathology of "persistent vegetative state" (survivals 1 month to 8 years): Brain 123: 1327, 2000. It is not rare for the cortex to be normal, but the thalamus and/or the deep white are never normal.

{00165} diffuse hypoxic-ischemic injury, old; note the laminar necrosis
{33033} diffuse hypoxic-ischemic injury, old
{31970} diffuse hypoxic-ischemic injury, old

Diffuse hypoxic-ischemic injury
Old; patient kept alive on respirator
WebPath Photo

      The most severe variant is SPONGE BRAIN ("multi-cystic brain"), in infants who have severe hypoxic-ischemic injury around the time of birth but are kept alive for weeks afterwards.

{15469} sponge brain

      * Your lecturer is no expert on neurology or rehabilitation, but from what he's observed as a physician, he's formed the opinion that "neuro rehab" for the profoundly injured does less public or private good than most any other way of spending lots of money. See Lancet 357: 410, 2001 for a bitter editorial on the failure to show any benefit for neurodegenerative disease; the sorry truth about stroke rehab is summarized in Stroke 34: 801, 2003. If you have other information, I'd like to hear about it. One of my correspondents (2009), a neuro nurse with much experience, was impressed anecdotally, and suggests that it might reasonably be taught to and tried by family members. Anyone with clinical experience will recognize the wisdom of her last remark: "Also, the hope the family has is sometimes all they have, and puttng their loved one through the motions can give the family something to do, some control and if it helps, less reliance on caregivers."

CEREBRAL INFARCTS

    "Stroke", the sudden onset of a permanent, localized neurologic deficit, may result either from infarction or hemorrhage, and has a multitude of specific causes. The most common cause of stroke (75%) is cerebral infarction (annual incidence 190 per 100,000 people per year).

Pathology of Stroke
Some great photos
From Wash. U.

Cerebrovascular disease
Text and pictures
From "Big Robbins"

    Infarcts have many causes.

      THROMBOTIC INFARCTS usually result from atherosclerosis, when a plaque ruptures. Favored sites are the carotid bifurcations and the vertebrobasilar system.

      EMBOLIC INFARCTS typically result from atheroemboli or emboli from intracardiac thrombi (i.e., thrombi from fibrillating atria, mural thrombi over old infarcts). Especially, remembers an ulcerated atherosclerotic plaque in the ascending aorta. See NEJM 334: 2126, 1996; Am. Heart J. 139: 329, 2000). Emboli most often go to one or the other middle cerebral artery.

        In a kid with a stroke, think of patent foramen ovale and pulmonary hypertension (* easy screen using trans-esophageal sonography: Am. J. Card. 74: 381, 1994).

        Nobody understands why for sure, but current smoking greatly increases your risk of stroke (Ann. Int. Med. 120: 458, 1994).

        * Some folks lack one or both posterior communicating arteries, and these people are much more vulnerable to embolic stroke (i.e., no collaterals): NEJM 330: 1565, 1992.

        You also remember that the little arteries that supply the thalamus and basal ganglia don't have collateral circulation, so little strokes here are common.

      We have already seen infarcts due to compression of vessels during herniation, and "border zone infarcts" in which there is hypoperfusion but no obstruction.

      You already know SUBCLAVIAN STEAL SYNDROME (Robin Hood syndrome, etc.), in which a patient with occlusive atherosclerosis of a proximal subclavian artery suffers brainstem syndromes upon exercising the arm on the involved side. The arm is being perfused via blood that goes up the contralateral vertebral artery, and back down the ipsilateral one.

      * (Primary) GRANULOMATOUS ANGIITIS OF THE CNS is a thankfully rare entity that may be suspected on scan, but needs confirmation on leptomeningeal biopsy (Neurology 53: 858, 1999). Immunosuppression (as for Wegener's and polyarteritis nodosa) is the basis of treatment.

      * MOYAMOYA DISEASE, a poorly-understood process in which the vessels of the circle of Willis and nearby become narrowed (fibrosis of the intima) and may also bleed (fragile new vessels sprout), is yet another cause of stroke. This is fairly common in both children and adults (J. Neurosurg. 77: 84, 1992; J. Neurosurg. 80: 328, 1994; Arch. Neuro. 58: 1274, 2001). The etiology is still obscure; it may occur in syndromes (Am. J. Op. 127: 356, 1999), including Down's and sicklers. Prognosis after a pial revascularization procedure is excellent: J. Neurosurg. 100(S2): 142-9, 2004. Update NEJM 360: 1226, 2009.

      * CADASIL, or cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, is a grisly disease caused by buildup of granular material in the basement membranes between the smooth muscles of arterial walls. The diagnosis is made when the pathologist examines a skin biopsy. The arteries have fragmented internal elastic membranes and basophilic, PAS-positive granules throughout their walls. It is underdiagnosed; this may change since there is supposedly a pathognomonic MRI. The gene's name is Notch3. See Lancet 350: 1490, 1997, Nature 383: 707, 1996; alleles Brain 132: 1601, 2009; anatomic pathology Neurology 51: 844, 1998. Progressive loss of cognitive function correlates with the little strokes and bleeds (Neurology 72: 143, 2009).

      * SUSAC SYNDROME ("retinocochleocerebral vasculopathy"; Medicine 77: 3, 1998) is another, thankfully rare (but perhaps underdiagnosed) syndrome of small vessel spasm in the eye, inner ear, and brain. The physician will see occlusions of branches of the retinal artery plus sensorineural hearing loss. It usually affects young adult women and vanishes after a year or so.

    Future hematologists: Remember LEUKOSTATIC INFARCTS throughout the brain when the white count is extremely high and stops up the microvasculature (i.e., chronic granulocytic leukemia).

    The ability to survive a stroke depends on the availability of collateral flow.

      For example, an intact circle of Willis supplied by good arteries renders complete occlusion of a carotid artery innocuous, and collateral flow from the anterior cerebral artery may protect much brain during occlusion of the middle cerebral artery. (Basilar artery atherosclerosis, however, generally cannot be overcome by good collateral flow).

      For some reason, the small, deep-brain cerebral arteries do not anastomose much. When one is occluded, an infarct is inevitable. This is unfortunate, since these arteries supply such key structures as the internal capsule.

    The classic brain infarct is ISCHEMIC ("anemic", "bland"), and the morphologic changes are stereotyped.

      Six to twelve hours after the "stroke", the brain becomes slightly discolored and soft, blurring the gray-white junction. You usually see at least a few petechiae at the edges (why?).

        * Just as you'd expect, early treatment to lyse the thrombus improves outcome, but at increased risk of intracranial hemorrhage (NEJM 359: 1317, 2008).

      Two to three days after the "stroke", the cerebral matter becomes very soft, and starts to break up. At this time, surrounding edema may be quite severe, enough to produce herniation.

{00180} infarct with early softening
{17792} infarct with early softening

Brain infarct
Acute
WebPath Photo

Brain infarct
Acute
WebPath Photo

Fresh infarct

WebPath Photo

Intermediate age infarct

WebPath Photo

Intermediate age infarct

WebPath Photo

Fresh infarct

WebPath Photo

Intermediate age infarct

WebPath Photo

Intermediate age infarct
Lots of macrophages eating lipid
WebPath Photo

Intermediate age infarct

WebPath Photo

"Cystic" infarct

WebPath Photo

Cerebral Infarct
Australian Pathology Museum
High-tech gross photos

      As the infarct heals, the dead tissue liquifies, leaving a cavity that is typically still crisscrossed by little surviving blood vessels. The overlying leptomeninges (when involved) become thick and form the roof of the cavity. It takes months for a big infarct to transform into a RESIDUAL CAVITY ("cyst", a time-honored misnomer).

{00189} infarct, breaking apart
{06348} infarct, old; frontotemporal area
{10350} infarcts, old and recent
{10960} infarct, old, basal ganglia
{17694} infarct, old

Carotid thrombus

WebPath Photo

Organized thrombus

WebPath Photo

Fresh stroke
Some small hemorrhages
Wikimedia Commons

      Recovery of function after a cerebral infarct (or hemorrhage) is due largely to resorption of edema fluid.

      Microscopically, polys and then macrophages clean up the debris, just as in a myocardial infarct. Unlike in the rest of the body, the macrophages stay around for years. Instead of a fibrous scar, the infarct is surrounded by gliosis.

      HEMORRHAGIC INFARCTS are "anemic infarcts" complicated by dissolution of an embolus or backflow of blood from the margins. The result is perfusion of non-viable blood vessels, which rupture.

        Infarcts consist of lots of petechiae (since the vessels that break are capillaries); they may be confined to the gray matter (the vessels in white matter typically do not rupture in this setting).

{18760} hemorrhagic infarct; note it consists of petechiae
{00145} hemorrhagic infarct

Hemorrhagic infarct

WebPath Photo

Infarct with petechiae

WebPath Photo

        Of course, if somebody anticoagulated the patient, the hemorrhage will be much more impressive and dangerous. Anticoagulation is a two-edged weapon in stroke.

    VENOUS INFARCTS result from hypercoagulable states (remember polycythemia vera, sickle cell disease, lupus anticoagulant, and the post-partum state in adults, and dehydration in children) or infected (TB, H. 'flu, others) venous sinuses. Infarction will not occur without thrombosis either of very large venous sinuses or many small veins. The typical case shows hemorrhagic infarction, symmetrically around the superior sagittal sinus.

    Cerebral Venous Thrombosis
    Pittsburgh Illustrated Case

{15696} venous infarct
{15697} venous infarct

* Lenin's brain contained multiple, bilateral, old infarcts. See Neurology 42: 241, 1992. This disproves his friend Maxim Gorky's maxim that a bad person needs a good brain.

INTRACEREBRAL HEMORRHAGE

Brain Hemorrhages I
From Chile
In Spanish

Brain Hemorrhages II
From Chile
In Spanish

    There are many different types of brain hemorrhages. Some rules:

      Blood in the ventricles is noxious, and if the fourth ventricle is suddenly dilated under pressure, death results.

      Blood in the subarachnoid space is excruciatingly painful.

      Bleeding in the brain substance itself is more subtle, and can present merely as nausea.

      Fresh bleeding produces spinal fluid of normal color, or slightly pink. Xanthochromia results when breakdown products of hemoglobin stain the CSF yellowish.

    Bleeding into the brain substance is attributed to a variety of causes.

    • "hypertension"
      • NOTE: This "clinical truism" ("He popped his cork!") is disputed by some autopsy pathologists who note that there is a reflex rise in systemic blood pressure when intracranial pressure rises ("Cushing reflex", remember?), and that victims of intracranial hemorrhage often lack other stigmata of longstanding systemic hypertension (i.e., no big heart, no bad kidneys). Wait for my series -- so far, mine all have cardiac hypertrophy from high blood pressure.

    • bleeding disorders (very common; remember the leukemias)
    • hemorrhage into brain tumors (primary, metastatic)
    • congophilic (amyloid) angiopathy (hereditary, idiopathic; "Alzheimer's amyloid angiopathy" generally does not bleed). Bleeding amyloid angiopathy is a neurosurgeon's nightmare, because all the vessels are extremely brittle. There also tend to be strokes (Neurology 72: 1230, 2009). ().
    • vascular malformations ("angiomas")
    • mycotic aneurysms (rare)

    Taking all these causes together, these bleeds are fairly common, with an incidence of 35 per 100,000 people per year.

    The classic "hypertensive" hemorrhage (whether or not hypertension is the cause) is classically thought to result from rupture of a little "Charcot-Bouchard" micro-aneurysm (<=2-3 mm) on the trunks and at the bifurcations of small intracerebral arteries. We do not know why these form, and we don't know whether hypertension contributes to their formation, makes them rupture once formed, or whatever.

      * Medical history buffs: Dr. Charcot is famous as teacher of Freud and the other great neurologists of the era, discoverer and namer of multiple sclerosis, characterizer of Charcot-Marie-Tooth disease and the nerve-deprived Charcot joint, and the founder of "Arch. Neuro." Probably his greatest legacy is studying the emotional overlay of illness.

    The distribution of "hypertensive" hemorrhages given in "Big Robbins" is worth remembering:

      55%... putamen
      15%... deep centrum semiovale
      10%... thalamus
      10%... pons (very bad location....)
      10%... cerebellum

{00144} intracerebral hemorrhage
{01813} intracerebral hemorrhage
{01815} intracerebral hemorrhage
{09476} intracerebral hemorrhage

Hypertensive basal ganglia hemorrhage

WebPath Photo

Hypertensive basal ganglia hemorrhage

WebPath Photo

    Death results from herniation or distention of the fourth ventricle by blood.

      Note that, in one sense, a hemorrhage is more serious than an infarct of the same size, since there will be more edema and opportunities for herniation.

      When the clot is resorbed, however, the surrounding tissue generally regains much of its function. Survivors of hemorrhages are likely to have some disability, though not nearly so much as in an infarct of the same size.

    Grossly, look for surrounding edema (and maybe herniation), extravasation of blood into the subarachnoid space and/or ventricles, and a big clot on sectioning.

      If present for a while, you'll see blood pigments (bilirubin, biliverdin, later hemosiderin) near the clot.

      If the patient recovers, you'll see a slit ("post-apoplectic cavity") surrounded by gliosis.

* Actor Richard Burton, just before he died of an intracerebral hemorrhage, scribbled these lines from Macbeth in his notebook: "The multitudinous seas incarnadine, making the green one, red" (i.e., Macbeth sees his victim's blood flowing so copiously as to turn the sea red)....


Macbeth

NON-TRAUMATIC SUBARACHNOID HEMORRHAGES (Lancet 369: 306, 2007)

    These bleeds are fairly common, with an incidence of 25 per 100,000 people per year.

      The usual cause of non-traumatic bleeding into the subarachnoid space is rupture of a "berry" ("congenital" aneurysm).

      Considerably less common is bleeding from a vascular malformation; ruptured mycotic aneurysms are thankfully rare but worth remembering (Am. J. Med. Sci. 339: 190, 2010).

      You are already familiar with trauma as a cause of subarachnoid hemorrhage. In addition to skull fractures. Remember a blow to the head with twisting of the neck Am. J. For. Med. Path. 24: 114, 2003).

    BERRY ANEURYSMS

      Old ideas about "gaps in the internal elastica of the arteries at the bifurcations" as direct cause are wrong; just about everybody has these gaps.

      Hypertension, often cited, is a dubious risk factor. Some people claim it promotes degeneration of the elastica over time.

      One known risk factor is autosomal dominant ("adult") polycystic kidney disease. Checking these patients' heads for berries: NEJM 327: 916, 1992.

      Having a relative who had a berry quadruples your risk: Lancet 349: 380, 1997.

      Berries are often multiple, and tend to undergo thrombosis and even calcification. They may grow over time, berries as small as 3 mm can rupture, and if they get to 6-10 mm, rupture is common.

      "Big Robbins" lists these sites favored by berry aneurysms:

        40%... Anterior communicating artery, adjacent to the anterior cerebral arteries

        34%... Middle cerebral artery, where it bifurcates in the Sylvian fissures

        20%... Posterior communicating artery, adjacent to the middle cerebral artery

          4%...Bifurcation of the basilar artery into the posterior cerebral arteries

        Although tiny "berries" are common at autopsy, you'll see a big one in about 2% of routine autopsies of adults.

      The thin, fibrous wall of the aneurysm is the site of rupture.

        The blood may be forced directly into the brain substance and from there into the ventricles. (Free blood is noxious to brain, especially under these circumstances.)

        More classically, the blood erupts into the subarachnoid space, producing excruciating pain, followed by progressive neurologic problems.

          Organization of the resulting mass of blood produces hydrocephalus by plugging the basal foraminae.

          Vasospasm (which develops after a few days) can produce additional cerebral damage.

        Many patients die soon after the bleed, or during re-bleeding. Others recover fully. Still others suffer persistent vegetative state.

          * In 1986, fireman-hero Paul Brophy became the first American to die following court-authorized discontinuation of nutrition and hydration. Prior to the subarachnoid hemorrhage that put him in persistent vegetative state, he very explicitly and unequivocally stated that he did not want to live under such conditions. His family had to drag the attending physician and hospital all the way to the Massachusetts Supreme Court to win him (and us) the right to die under these circmstances. Some details of this case are especially ugly; ask me if you like.

        * Long-mysterious, the hyponatremia and excess urinary sodium loss in patients with ruptured berries now seems to be due to brain natriuretic peptide (Lancet 349: 245, 1997).

{15656} berry aneurysm, ruptured
{15667} berry aneurysm,
{17699} berry aneurysm, PICA
{17712} berry aneurysm, ruptured
{18754} berry aneurysm, ruptured

Brain Aneurysms
From Chile
In Spanish

Berry aneurysm

WebPath Photo

Berry aneurysm

WebPath Photo

Subarachnoid bleed from berry aneurysm

WebPath Photo

Berry aneurysm
Incidental finding
KU Collection

    VASCULAR MALFORMATIONS may bleed into the subarachnoid space, the brain substance, or both.

      ARTERIOVENOUS MALFORMATIONS (masses of large blood vessels) tend to be located in the hemispheres. Review Lancet 359: 863, 2002.

        * Future radiologists: There are other CNS vascular malformations, including those made only of veins, and those made only of capillaries. These are much less likely to cause problems, but the new radiographic techniques are picking these up fairly often (Surg. Neurol. 48: 175, 1997)

{10848} AV malformation
{10849} AV malformation
{18759} AV malformation

AV malformation

WebPath Photo

Cryptic AV malformation
Pittsburgh Pathology Cases

AV malformation

WebPath Photo

AV malformation

WebPath Photo

      CAVERNOUS HEMANGIOMAS, when they occur in the brain, typically ooze small amounts of blood. They are unlikely to cause massive bleeding, but tend to cause seizures.

{15661} cavernous hemangioma
{15662} cavernous hemangioma

        A large cavernous hemangioma in the meninges (as in Sturge-Weber syndrome) can steal blood away from a cerebral hemisphere.

          * The same phenomenon in the spinal cord is called "Foix-Alajouanine syndrome".

      TRAUMATIC RUPTURE OF A VERTEBRAL ARTERY occasionally causes hemorrhage. There may be an actual bursting or tearing in extreme trauma, or a medial dissection and/or a brainstem stroke in less severe trauma. Reported causes incude violence (For. Sci. Int. 182: e15, 2008), surgery, and angiography.

        There is also a good deal written on injury to the vertebral arteries during high-velocity neck manipulation. This seems to be more likely to produce medial dissection and stroke. See J. Neurol. 253: 724, 2006; Acta. Neurol. Scand. 112: 349, 2005; J. Neuro. 250: 1179, 2003; Neurology 60: 1424, 2003. Be aware of vertigo as the first warning (Emerg. Med. J. 23: e1, 2006).

      CAPILLARY HEMANGIOMAS do not bleed, and are incidental curiosities at autopsy.

    GERMINAL PLATE HEMORRHAGES in premature babies are worth mentioning here. These are bleeds into the ventricles, rather than the subarachnoid space. The usual setting is a preemie with respiratory difficulty and cor pulmonale; the prognosis is grave if there is rupture through the ependyma into the ventricles ("intraventricular hemorrhages"; * a regrettable misnomer calls a bleed with no blood in the ventricles an "intraventricular hemorrhage grade I").

      Angiogenesis inhibitors (celecoxib, etc.) to prevent germinal plate bleeds in preemies: Nat. Med. 13: 477, 2007.

{00521} germinal plate bleed, small
{09518} germinal plate bleed, large

Germinal plate, normal
WebPath Photo

Germinal plate hemorrhage
WebPath Photo

Germinal plate hemorrhage
WebPath Photo

Germinal plate hemorrhage

WebPath Photo

    ATHEROSCLEROTIC ANEURYSMS in the head are typically fusiform dilatations of the basilar artery. These seldom rupture, but they may undergo thrombosis (bad!) or even damage the brainstem and its nerves by compression.

HYPERTENSIVE CEREBROVASCULAR DISEASE

    In addition to its (questioned) relationship to hemorrhage, and its known relationship to atherosclerosis, hypertension causes several other cerebral problems.

    LACUNAR INFARCTS ("lacunae") are little infarcts, typically a few mm across, typically in the deep structures of the brain (the basal ganglia and nearby structures are typical sites).

      Classic neuropathology attributes them to hypertensive hyaline arteriolar sclerosis. However, there are often clusters of hemosiderin-laden macrophages at the periphery, suggesting that the real cause is microhemorrhages, which makes sense. Often, some of the lesions are brown-walled slits that must have resulted from hemorrhages.

{09446} "êtat criblé", French for multiple lacunes

Lacunar infarct
H&E
KCUMB Team

Lacunar infarct
Silver
KCUMB Team

Lacune

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Lacune

WebPath Photo

    BINSWANGER'S SUBCORTICAL LEUKOENCEPHALOPATHY (Neurology 46: 291, 1996; Am. Fam. Phys. 58: 2068, 1998)

      This describes demyelinization, gliosis, and maybe actual lacunar infarcts of the white matter of the centrum semiovale beneath the cortex ("white matter hyperintensities", "leukoaraiosis"), producing "Alzheimer-like" progressive dementia.

      We believe the cause of this lesion is ischemia secondary to hyaline arteriolar sclerosis of hypertension.

      This is coming to be much better known than in the past, and with new imaging studies, we've found that when notable white matter changes are discovered incidentally in an older person, that person will probably have rapid, global decline in function (BMJ 339: b2477, 2009).

        * Homocysteine-induced endothelial cell dysfunction also seems to be a major risk factor: Brain 127: 212, 2004; Arch. Neuro. 59: 787, 2002.

      Since this is a subcortical process, expect rigidity, gait, and bladder problems.

      In spite of what anyone else may tell you, Binswanger's is common, and is one of the great "unnoticed diseases" of the late twentieth century (common illnesses that until recently were overlooked routinely. )

        It's fairly common for patients diagnosed as having "Alzheimer's disease" in life to turn out at autopsy to have Binswanger's instead. Stay tuned; the public will learn about "Binswanger's" soon.

        Vascular dementia update: Med. Clin. N.A. 86: 477, 2002.


      Dr. Binswanger
      * Fun to know: Louis (Ludwig) Binswanger was a Swiss neurologist-psychiatrist who studied under Freud, Jung, and Bleuler. He was the first person to relate psychotherapy and existentialism. He even got a tribute in the "Journal of Existentialism" when he died in 1966. You may find Viktor Frankl's works more accessable.

      It sounds corny today, but the idea that mental therapy should focus on the here-and-now, doing your own thinking (including meaning and answer-for-death), accepting life even when it is not perfect, and taking responsibility for your outcomes was radical in its day (notably the 1950's). We can thank the existentialists (or maybe just common sense.)

      Click here for an English translation of the table of contents of Binswanger's book, and decide for yourself why the full work remains untranslated into English.

      Whatever you think of existentialism (the dominant secular philosophy when your lecturer was growing up), I hope you will not be shy about talking with people about their personal searches for meaning, authenticity, commitment, being something real, and taking responsibility for their own lives.

    HYPERTENSIVE ENCEPHALOPATHY

      Sudden or extreme rises in blood pressure produce brain dysfunction.

        Patients complain of confusion, drowsiness, headache, and nausea. Seizures are also common.

        After taking the blood pressure, clinicians look for retinal bleeds and papilledema.

      We don't understand all the mechanisms involved, but at high pressures, autoregulation of blood flow breaks down, and the blood-brain barrier is compromised, with resulting cerebral edema.

        In fatal cases, we find necrotic blood vessels, much like in the kidney in "malignant hypertension".

NERVOUS SYSTEM TRAUMA

CNS TRAUMA

    This is a common, grave problem that (as we have noted) causes much death and disability. There are perhaps 350,000 head injuries in the USA each year, and there are 3.3 million Americans living with disability from neurotrauma (J. Neurosurg. 112: 1125, 2010).

      Damaged neurons undergo apoptosis, or their axons can be severed. The astrocyte foot processes are removed from the endothelium by trauma, with loss of the blood-brain barrier. New astrocytes migrate to the area where proteins have wandered in; they make matrix that seals the leaks ("glial scar").

      Ten percent of disabling injury is brain injury.

      In 1/3 of all "accidental deaths", the cause is brain injury.

      In 2/3 of automobile deaths, the cause is brain injury.

      * Eye-opening article about brain trauma on the job (with suggestions as to who might do well to wear a helmet): Am. J. Pub. Health. 84: 1106, 1994. The "average" industrial worker has one chance in ten-thousand of suffering brain damage each year, but the risk varies tremendously from job to job.

      * Head injuries in young athletes: Med. Clin. N.A. 78: 289, 1994. Safety stuff; required reading for any physician involved with sports. Whether stem cell treatment will help in acute neurotrauma, as it seems to do in acute myocardial infarction, remains to be seen (J. Neurosurg. 112: 1125, 2010). Beatings to the head (i.e., political prisoners) do seem to result in thinning of the cortex (Harvard torture survivor study); the study also confirmed that both past torture and past beatings do cause the amygdala to shrink (Arch. Gen. Psych. 66: 1221, 2009).

    SKULL FRACTURES may be of many types (even "occult").

      You already know about CSF rhinorrhea. Again, beware the patient with a "runny nose" or "runny ear" and check the "snot" for glucose with a urine dipstick!

      Bone fragments may injure the brain ("fracture contusions"), and infection may enter this way.

      "Big Robbins" rightly points out that skull injury and brain injury do not necessarily go together.

      An "open" ("compound") skull fracture (i.e., one with an overlying tear in the scalp will, of course, serve as a portal of entry for bacteria.

    SUBARACHNOID HEMORRHAGE and SUBDURAL HEMORRHAGE are both common after severe head injuries; different authorities will cite one or the other as "more common".

    EPIDURAL HEMATOMAS are accumulations of blood between the skull and the dura.

{18753} epidural hematoma

Epidural hematoma

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      Usually the middle meningeal artery has been severed (i.e., there has been a skull fracture crossing this vessel). Arterial bleeding causes these lesions to progress rapidly.

      The typical story ("talk and die") is a blow to the head, with (or without) loss of consciousness, recovery, then progressive neurologic deterioration leading to coma and herniation. Once the process starts, death is almost certain unless the hematoma is evacuated (i.e., the bleeding will not stop on its own). This is a neurosurgeon's emergency, in which minutes count.

        Your lecturer believes that the only brain injuries that CANNOT give a "talk and die" scenario are those with brainstem diffuse axonal injury. This makes determining the perpetrator in shaken-baby cases a bit more difficult. See below.

      In 2009, Natasha Richardson's decisions not to wear a helmet on the ski slopes, and then not to accept care after a head injury, tragically cost her her life.

    SUBDURAL HEMATOMAS result from avulsion and rupture of the bridging veins that pass between the brain and the large dural sinuses.

      These follow forceful displacement of the brain within the skull (i.e., inertial injury, when the skull stops but the brain continues moving); for this reason, look for them where the brain has the greatest opportunity to slide (i.e., over the cerebral convexities, often bilaterally).

      In ACUTE SUBDURAL HEMATOMA following massive trauma, there is obvious severe injury and the prognosis is serious. Small ones after minor falls and so forth are more survivable.

        With folks getting scanned after every head injury, we've come to recognize that (1) some folks can indeed have a lucid interval despite a subdural hematoma; (2)* bleeding can be from bridging veins or cortical veins, or (less often) from cortical arteries. Boxers: J. Trauma 66: 298, 2009.

      SHAKEN BABY SYNDROME (Arch. Path. Lab. Med. 133: 619, 2009; Arch. Dis. Child. 91: 205, 2006) has had its share of dogmatists and faddists but is now being sorted out. Most kids are under age 2 but a few are older (Pediatrics 117: e1039, 2006. (I disagree with "experts" who believe there is always an impact. So does the NYC medical examiner, Arch. Path. 2009 above. A new series analyzing statements by perpetrators supports this: Arch. Ped. Ad. Med. 158: 454, 2004, do bear in mind that these confessions may not be truthful, as people would be less ashamed of shaking than of slamming.) The key is the sudden torque forces complied with acceleration-deceleration.

        As common sense would tell you, it's a spectrum:

        • obvious tearing of fiber tracts in the brainstem and upper cord; small or absent subdural / retinal bleeds (no time), immediate coma, death on the scene or minutes after
        • large subdural hematomas, deep intracerebral pathology suggesting damage to the reticular activating system if you look hard for it; may be obtunded rather than comatose but no lucid interval; severe retinal hemorrhages, high mortality
        • expanding subdural hematomas but without clinical evidence of deeper intracerebral pathology, possibly lucid interval, the baby may simply seem to grow more lethargic as the head expands visibly; there may not be retinal hemorrhages. This is the only category that may have an innocent explanation, i.e., short fall with twist.

        * Don't confuse any of these with the intradural bleeds that are commonly seen in babies dying from any cause, or the tiny subdural bleeds that are occasionally seen in babies dying of other illnesses or getting scanned. (Small subdurals result fairly often from the birth process and do not seem to be problematic. See Lancet 363: 846, 2004). This generated some pop-media confusion in early 2003. I have never taught that hemorrhages with folds near the macula are pathognomonic of child abuse, and it's now quite clear this was never true.

        On the other hand, severe retinal bleeds in a child are pretty much diagnostic of abusive trauma rather than an accident (J. Neurusurg. 102(S4): 380, 2005, others). The most recent credible counter-example: Ped. Neurosurg. 43: 433, 2007; of course, there has long been a minority opinion that retinal hemorrhages and death can result from short-distance accidental falls (Am. J. For. Med. Path. 22: 1, 2001).

        It's possible that the subdural hematomas of infants, which tend to form a thin film on both sides of the head rather than a single mass lesion on one side as seen in older kids and adults, have a different mechanism of formation -- this is up for discussion (For. Sci. Int. 187: 6, 2009. Scan newborns and you'll discover maybe 50% have a small subdural from getting born.

        After shaking, the child is never normal and obviously needs medical care (Child Abuse & Neglect 21: 929, 1997), but may deteriorate later (J. For. Sci. 43: 723, 1998).

{00533} acute subdural hematoma
{18758} acute subdural hematoma
{32107} acute subdural hematoma

Acute subdural
Bryan Lee

Acute subdural hematoma

WebPath Photo

      In CHRONIC SUBDURAL HEMATOMA, neurologic impairment follows minor trauma and leads to the discovery of the organizing clot, which is removed. (The clot may shunt blood away from the underlying brain, and the large, delicate area of granulation tissue is prone to re-bleed and therefore grow.)

{32110} chronic subdural hematoma
{32112} chronic subdural hematoma; despite the red, note the membrane

Subdural hematoma
Great x-ray
Pittsburgh Pathology Cases

Chronic subdural hematoma

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Chronic subdural hematomas

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        Veins are more likely to break if the brain is a bit atrophic (alcoholism, old age) and/or there is some problem with coagulation (i.e., alcoholism).

        The CT scanner has greatly improved our ability to find these lesions. (* The fictional Hans Brinker, of silver skates fame, became a neurosurgeon after seeing his father's remarkable recovery from a chronic subdural hematoma after surgery.)

        * Future pathologists: Dating subdural hematomas depends on old studies from the 1930's. For example...

        • Fibroblastic activity means "36 hours or more"
        • Hemosiderin laden macrophages means "five days or more"

      * As above, a SUBDURAL HYGROMA results from a tear in the arachnoid.

    CONCUSSION simply means any change in mentation immediately following a blow (JAMA 266: 2867, 1991 sports). Consciousness need not be lost. The anatomic correlates are just being worked out (Neurosurg. 56: 364, 2005), and "Big Robbins"'s idea about twisting the midbrain reticular activating system sounds as good as any.

      After even the slightest concussion, the brain's ability to adapt to a second blow is much-diminished; hence "second-impact syndrome". Keep the athlete out of play after even the slightest episode of wooziness. Review Clin. J. Sport. Med. 11: 194, 2001. This is a consensus nowadays. This is a very big deal in any contact sport right now.

    CONTUSION (bruising) and LACERATION (tearing from being overstretched) are analogous to their counterparts in general pathology. Expect some hemorrhage with each.

      All contusions result in permanent brain damage.

      COUP CONTUSIONS result from a blow to the unmoving skull that damages the underlying brain tissue without rupturing the pia. Look for cone-shaped lesions with their bases along the apices of the gyri; fresh contusions will show small hemorrhages (from capillaries) and necrosis, while old contusions show gliosis and hemosiderin pigmentation ("plaques jaunes", or "yellow plaques"); these are considered to be epileptogenic foci. Today, pathologists also look for axonal spheroids (diffuse axonal injury).

{00155} cone-shaped coup contusion. He got hit bad on the left side of the head.
{17779} old contusion
{17780} coup contusion

      CONTRECOUP CONTUSIONS (contracoup contusions) result from the brain bouncing against the side of the decelerating skull opposite the point of impact (typically a floor or other large, immovable object). The pathology is similar to "coup contusions".

      The bony structures of the skull itself can cause contusions in surprising places. Classic sites include the frontal lobes just above the orbital plate (from falling backwards off bar stools), and the bottom portions of the temporal lobes that overlie the petrous ridges.

{00545} contrecoup contusion (classic site, bottom of temporal lobe)
{25618} contrecoup contusion
{25617} contrecoup contusion

Contracoup injury

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Contracoup injury

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Contracoup injury, old

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Contracoup injury, old

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      TRAUMATIC INTRACEREBRAL HEMORRHAGES have been listed by "Big Robbins" as mysterious consequences of head trauma. Probably they result from tearing of the vessels themselves by mechanical forces.

    DIFFUSE AXONAL INJURY results from rupture of axons by shearing forces.

      It probably accounts for residual brain damage after trauma that is not visible grossly, by classic histopathology, or on scans.

      Grossly, look for petechiae in the corpus callosum, where the forces come together. Silver stains show many damaged axons with axonal spheroids (retraction balls, where axoplasmic transport has stopped).

        * Neuropathologists may see some reactive macrophages. Histopathology: Arch. Path. Lab. Med. 118: 168, 1994 (this crew prefers the good-old H&E stain over anything fancy; ubiqitin has been a popular immunostain though now amyloid beta precursor βAPP is preferred).

      If the patient survives a long time, there may be loss of myelin, macrophage reaction, and so forth.

      * Science marches onward. A standard rat model for diffuse axonal injury is now available, involving dropping a 1-pound weight 1 or 2 meters onto the animal's skull (J. Neurosurg. 80: 291 & 301, 1994).

      * There is less traumatic axonal injury in "shaken baby syndrome" than one might expect, at least if we are to believe the immunostains. See Brain 124: 1299, 2001; J. Neurotrauma 20: 347, 2003. The damage is primarily "vascular axonal injury", from the massive edema stretching the axons.

Diffuse axonal injury
Bryan Lee

Shaken baby
Axonal spheroids
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Motor vehicle fatality

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    The histology of acute physical brain trauma is not very helpful in determining the exact time of injury. You can see neutrophils, swollen axons, and red neurons within an hour (and encrusted, i.e., calcified, neurons within 3.)

    Patients "in coma" from trauma often are surprisingly aware of their environment and caregivers' behavior, and remember after. Be advised, and be kind. See J. Neurosurg. Nurs. 20: 223, 1988.

    NEUROPATHOLOGY OF BOXERS is seen years after blows to the head. It begins with mild disturbances of mood and coordination. Later, there is mild dysarthria, paranoid ideas, and/or resting tremor. Eventually, immature and aggressive behavior, impaired memory, hyperreflexia, and poor coordination are likely to develop. Thankfully, only about 20% of boxers are ever affected; risk factors include how much you've been hit, and your apo-E type (JAMA 278: 136, 1997; Semin. Neurol. 20: 179, 2000) like in Alzheimer's. Where dementia has occurred, there are neurofibrillary tangles histochemically very much like those of Alzheimer's (Am. J. Path. 136: 255, 1990; J. Neurol. Neurosurg. Psych. 53: 373, 1990). Traditionally, it's been taught that there are no senile plaques -- reaffirmed Arch. Neuropsych. 65: , Sept 2007. (This is being re-evaluated -- it's hard to tell whether an aging boxer has chronic traumatic encephalopathy or just happens to have early Alzheimer's.) Parkinsonism is common. One classic study found the neocortical neurofibrillary tangles in boxers to be in the superficial layers, while in Alzheimer's they were as abundant in the deep layers (Acta. Neuropath. 85: 23, 1992). Cavum septum pellucidum is fairly distinctive for boxers. Boxing injuries JAMA 261: 1463, 1989.

      NOTE: Boxing is a poor-boy's sport in which the object is to scramble the other guy's brain enough to render him unconscious. Amateur boxing is a variant with headgear and tight regulations that keep injuries to a minimum. It is far safer than tackle football, but many people object to people hitting each other. Whether or not physicians approve of the sport, it will continue to find participants who want to improve their fighting skills and/or who want to be respected and safe on mean streets and/or who dream of big money. Some people say it's unethical for physicians to "support" the sport by caring for boxers. I respect this but do not agree.

    SHOCK THERAPY (ECT, electroconvulsive therapy) is an old psychiatric treatment that was popular for the mentally-ill in the pre-phenothiazine era. In the 1960's, office units made it extremely lucrative, and certain unethical psychiatrists made fortunes shocking every unhappy person who came to them. At the same time, leftist writer Ken Kesey misrepresented it as torture in his too-influential "One Flew Over the Cuckoo's Nest". The public believes that it dulls the mind over the long-term; though nobody has been able to show neuronal loss or other structural changes after shocking animals (Am. J. Psych. 151: 957, 1994), nobody's counted synapses or dendritic spines, either. I'll reserve judgement.

SPINAL CORD TRAUMA (review NEJM 330: 550, 1994)

    This results from gunshots, stab injuries, or vertebral column injury. "Big Robbins" rightly points out that:

    (1) In older people with cervical spondylosis, even small displacements of the cord can and do damage the nerves;

    (2) The associated bleeding ("hematomyelia") and neutrophilic infiltrate probably exacerbate the neurologic damage.

    Years after spinal cord injury, the site of trauma will still be obvious ("myelomalacia"). Look also for ("Wallerian") degeneration of the tracts, especially the posterior columns above the injury, and the corticospinal tracts below the injury.

Trivia: Lots of petechiae throughout the white matter? Fat embolus!

Fat embolus
Petechiae throughout white matter
KU Collection

Fat Embolus
Brain
WebPath Photo

Fat Embolus
Brain
WebPath Photo

Fat embolus

WebPath Photo

Fat embolus
Petechiae throughout white matter
KU Collection

CNS INFECTIONS

Pathology of nervous system infections
Great site
Yutaka Tsutsumi MD

Brain Inflammation I
From Chile
In Spanish

Brain Inflammation II
From Chile
In Spanish

INTRODUCTION

    Any pathogen can probably affect the CNS. MENINGITIS is inflammation of the leptomeninges (pia and arachnoid), ENCEPHALITIS is inflammation of the brain itself, and MENINGOENCEPHALITIS is inflammation of both. CEREBRITIS is a term for a bacterial infection of the brain that has not (yet) formed an abscess.

    One can have meningitis not due to infection (for example, a reaction to an intrathecally-injected medication or the release of fluid from a tumor), and there are autoimmune causes of encephalitis, but the unqualified terms imply infection. "Carcinomatous meningitis" is a misnomer for meningeal carcinomatosis, and sometimes the word "meningitis" is used to describe meningeal infections in which there is no inflammation (i.e., many cases of cryptococcosis). Don't worry about it.

ACUTE PYOGENIC MENINGITIS

Purulent meningitis

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Purulent meningitis

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Purulent meningitis

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Purulent meningitis

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Purulent meningitis

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Purulent meningitis

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Meningococcal meningitis

Yutaka Tsutsumi MD

Meningococci
Gram stain
WebPath Photo

H.'flu meningitis
Pus around base of brain
Wikimedia Commons

Bacterial meningitis
Thick purulent exudate
KU Collection

Bacteria in the spinal fluid
Rogues' gallery
Yutaka Tsutsumi MD

Klebsiella meningitis

Yutaka Tsutsumi MD

Listeria meningitis

Yutaka Tsutsumi MD

Flavobacterium meningitis
Advanced students
Yutaka Tsutsumi MD

Acute Meningitis
Text and photomicrographs. Nice.
Human Pathology Digital Image Gallery

Pneumococcal meningitis
CDC
Wikimedia Commons

Purulent meningitis
Great labels
Romanian Pathology Atlas

    Infection of the CSF around the brain, by classic bacteria. This was a classic infection that used to kill lots of people, including healthy young adults, and cause brain damage in many others.

      Organisms reach the CNS via the nose (? "passing through the cribriform plate" is supposedly the route of entry for the meningococcus; the bloodstream seems more plausible), neural tube defects, middle-ear infections, sinus infections, surgery, etc., etc.

    You will be quizzed frequently on the classically most-common etiologic agents:

      Strep B... At birth

      E. coli... First days of life

      H. 'flu... 1 month to 3-5 year old kids -- no longer chief culprit thanks to the vaccine (thanks Bill Clinton). (Nowadays it's rare and probably the pneumococcus.)

      Meningococcus... Older kids and younger adults (remember epidemics, military recruits, and the subtle, dreaded hemorrhage-necrosis in the adrenal glands called Waterhouse-Friderichsen syndrome)

      Pneumococcus... Oldsters and drinkers

      Listeria... The third most common cause nowadays, especially in young children, older adults and/or somewhat immunocompromised folks. Review Medicine 77: 313, 1998.

        You already know that listeria is also an important intrauterine and birth infection.

        It's a lawyer's disease, since contamined food is supposed to be the source.

        * Increased CSF lactic acid as a marker for listeria: Heart & Lung 36: 226, 2007.

      Anything... The immunosuppressed -- tough diagnosis

    Note that all these organisms are (or can be) part of the "commensal flora".

    Grossly, the CSF (normally crystal-clear) is turbid to frankly purulent.

      In fatal cases, the pathologist can second-guess the etiologic agent by the distribution of infection. H. 'flu meningitis tends to be basal, and pneumococcal meningitis tends to be worst around the sagittal sinus.

{32838} acute pyogenic meningitis (this happens to have been E. coli)
{10857} acute pyogenic meningitis
{26174} acute pyogenic meningitis
{31992} acute pyogenic meningitis

    On microscopy, neutrophils surround the leptomeningeal venules and may even pack the subarachnoid space. They will tend to follow the Virchow-Robin spaces into the brain matter itself.

    Patients present with fever, malaise, and meningeal signs (i.e., headache, stiff neck, irritability, photophobia, obtundation). Dread complications are numerous, even in the antibiotic era.

      Brain damage probably results mostly from occlusion of nearby blood vessels; only occasionally does the infection manage to penetrate the pia, but enough ischemia is produced to damage the nerve fibers (Neurology 62: 509, 2004).

      Hydrocephalus results from fibrosis around the basal cisterns. (Cryptococcal capsular polysaccharide promotes fibrosis.)

      Nerve damage may cause blindness, deafness, and/or other problems.

    Please have a high index of suspicion for all dread, treatable illnesses, particularly bacterial meningitis. Perform a lumbar puncture whenever you think of bacterial meningitis.

      Pneumococcal meningitis, perhaps because of its predilection for the elderly and drinkers, has the highest fatality rate of adult causes of meningitis.

    A SUBDURAL EMPYEMA, between dura and arachnoid but sparing the latter structure itself, usually results from extension of a skull or sinus infection. There is usually neck stiffness. If the pus is drained, the outcome is good. Today, imaging will show this.

      * Cervical subdural abscess from unsanitary acupuncture: J. Clin. Neuro. 11: 909, 2004.

    SPINAL EPIDURAL INFECTIONS generally represent extensions of osteomyelitis; INTRACRANIAL EPIDURAL INFECTIONS typically spread there from sinusitis.

    PACHYMENINGITIS is inflammation of the outer surface of the dura, almost always from nearby sinusitis or osteomyelitis.

      The venous sinuses may become infected by draining bacterial lesions of the ears, sinuses, or face; thrombosis is a consideration.

ACUTE LYMPHOCYTIC MENINGITIS ("viral meningitis", benign "stiff neck", etc.)

    Viral meningitis presents like bacterial meningitis, but usually is not so serious. Etiologic agents include mumps (thankfully rare nowadays), coxsackie and ECHO viruses, lymphocytic choriomeningitis (a ubiquitous, usually-trivial arenavirus caught from house mice), and herpes simplex II. (Don't laugh; around 20% of people who meet up with HSV II get an uncomfortable but mild viral meningitis with their first infection; it may recur and prove baffling Am. J. Med. 122: 688, 2009.)

    As you would expect, unless the CSF is tapped very early, there will be a predominance of lymphocytes rather than neutrophils. If the CSF pressure is very high (say, over 180 mm of water), you're probably not dealing with just viral meningitis.

    Most patients recover well after several very uncomfortable days. Sequelae are rare.

    * Future clinicians: Viruses and lymphocytes don't consume much CSF glucose as do bacteria and neutrophils, so CSF glucose levels will probably be normal in viral meningitis.

    MOLLARET'S MENINGITIS, or "benign recurrent aseptic meningitis", features real monocytes (making the diagnosis: Diag. Cytopath. 28: 227, 2003). Herpes I or II is often but not always the apparent cause (Eur. J. Clin. Micro. 23: 560, 2004). Some patients respond well to acyclovir; others do not. Review CMAJ 174: 1710, 2006.

CHRONIC MENINGITIS

    "Big Robbins" has said this usually means MENINGEAL TUBERCULOSIS, with granulomas, lymphocytes, and thick caseous debris concentrated around the basal cisterns, where cranial nerves are destroyed one by one, hydrocephalus results from scarring, and tuberculous arteritis infarcts the underlying brain. TB bacilli like the basal cisterns, because that's where the arteries come in and the oxygen levels are probably highest. Remember TB in AIDS meningitis, especially in communities with lots of TB: NEJM 326: 668, 1992. Remember that it takes weeks to grow the bug, and the bugs themselves may even be in the granulomas and not floating freely in the CSF. For more on TB, click here.

Tuberculous meningitis

Yutaka Tsutsumi MD

    CRYPTOCOCCAL MENINGITIS usually affects the immunosuppressed, in whom it produces virtually no inflammation. This is an indolent, insidious infection. Eventually, cryptococci can clog the CSF with their mucoid goo, and distend the Virchow-Robin spaces, creating the familiar "soap bubble" effect. (* NOTE: Dead cryptococci can persist in spinal fluid for years.) For more on cryptococci, click here.

Cryptococal meningitis

Yutaka Tsutsumi MD

Cryptococcal Meningitis
Pittsburgh Illustrated Case

Cryptococcosis
Infection in Virchow-Robin spaces
KU Collection

{06050} cryptococcus, PAS stain
{06055} cryptococcus, India ink preparation

    MENINGOVASCULAR SYPHILIS is an uncomfortable disease with plasmacytic vasculitis (with the familiar "obliterative endarteritis") as in other syphilis manifestations. The headache may be intractable. Look for fibrosis of the leptomeninges around the arachnoid granulations. Stroke may result. For more on syphilis, click here.

    CANDIDA can and does cause a fungal meningitis.

BACTERIAL INFECTIONS OF THE BRAIN

    CEREBRITIS, a bacterial infection that has not (yet) been contained as an abscesss. Most often this follows sepsis from any cause.

    BRAIN ABSCESS may result from a dirty wound, extension (remember mastoiditis), or septic emboli (lung infections such as bronchiectasis, left-sided bacterial endocarditis, right-to-left shunts through heart or lung).

      The usual etiologic agents are staph, strep, or anaerobes. But most any bacterium can be implicated; nocardia and actinomyces both cause a disturbing number of these. Note that the CSF will be sterile until the abscess ruptures.

      Since vessels are damaged, you are likely to see some real fibrous tissue near the abscess as it develops, in addition to gliotic scar.

      Brain abscesses are very bad, and patients have both systemic symptoms and focal signs. Death results from mass effect.

{00162} brain abscesses
{15544} brain abscess (three in the prefrontal lobes)
{27590} brain abscesses

Brain Abscess
Great labels
Romanian Pathology Atlas

Peptostreptococcal brain abscess

Yutaka Tsutsumi MD

Brain abscesses
Pittsburgh Pathology Cases

Brain abscess

WebPath Photo

Brain abscess, organizing rim

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MRI
Click on the brain abscess!

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    NEUROSYPHILIS takes four possible forms:

      MENINGOVASCULAR SYPHILIS (as above) produces headache and sometimes stroke.

      GENERAL PARESIS ("paretic syphilis"; "dementia paralytica") causes death of brain cells ("windswept cortex") and severe brain atrophy. Ask a neuropathologist to show you the "rod cells" (proliferated / wandering microglia). Patients seem to enjoy the early stages, with euphoria and mania; dementia eventually develops.

      By contrast, nobody enjoys TABES DORSALIS, destruction of the sensory nerves in the dorsal roots, with ataxia, loss of pain sensation and deep tendon reflexes, and the characteristic "lightning pains". Both axons and myelin are lost in the dorsal roots (hard to see) and posterior columns (easy to see).

      GUMMAS are important mass lesions, quite common in the poor nations.

    Traditionally, we have taught that one diagnoses neurosyphilis by finding FTA-ABS positive spinal fluid, and that this may be positive even if the blood test has reverted to negative. (Don't forget to check.) Especially in the HIV era, people are coming in with neurosyphilis with negative CSF serologies, and physicians are now even talking about making a presumptive diagnosis on the history and physical exam (!: Mayo. Clin. Proc. 82: 1091, 2007).

    * Neurosyphilis remains fairly common in the poor nations (J. Neurol. Neuros. Psych. 75: 1727, 2004).

{09027} tabes dorsalis, spinal cord, myelin stain

Tabes dorsalis, myelin stain
Dorsal columns at bottom
Classic drawing, Adami & McCrae, 1914

      Everyone seems to know the Argyll-Robertson pupil, which accommodates but does not react (* "just like a commercial sex worker with syphilis!")

      For more on syphilis, click here.

    LYME DISEASE can affect the brain much as does syphilis -- or it can mimic multiple sclerosis on imaging and clinically. More often, it produces a polyneuropathy, often involving the cranial nerves. Part of the story may be molecular mimicry -- flagellin from the bacterium induces antibodies that cross-react with a major protein in axons (Infect. Immun. 65: 1722, 1997). As you'd expect, this is one of the few causes of plasma cells appearing in a nerve biopsy. Use a Steiner silver stain to see the bugs.

    TUBERCULOMAS, with caseous debris in a granuloma, are still common mass lesions in the poor nations.

Lyme disease of the brain
Pittsburgh Pathology Cases

CONVENTIONAL VIRUS INFECTIONS OF THE BRAIN

CMV of the nervous system
Pittsburgh Pathology Cases

Encephalitis japonicum
Viral encephalitis
Yutaka Tsutsumi MD

    Many viruses affect the brain, and "tropism" determines which neurons or which parts of the brain they affect. The selectivity remains mysterious.

    Acute viral brain infections are typically complications of systemic viral illnesses (i.e., "flu-like syndromes").

    "Latent viruses" / "chronic persistent viruses" lie dormant for years (herpes 1 & 2, zoster, HIV; Epstein-Barr), while "slow viruses" (measles/SSPE, JC/PML) have a long latent period and produce a prolonged illness. Don't expect to always identify the virus from a case of fatal encephalitis, even with today's techniques.

    Many but not all cases of viral (and rickettsial) brain infections feature microglial nodules, with the microglia forming clusters in which some of the cells start looking like generic macrophages again.

    ARBOVIRUS ENCEPHALITIS may be due to the various "equine" (the reservoir is birds, not horses) or other encephalitis syndromes.

      Death or brain damage may occur, or the patient may recover completely.

      In the US, remember St. Louis encephalitis and West Nile; both are carried by mosquitoes, and the latter now kills at least 200 people yearly. Elsewhere in the world, Rift Valley and Japanese encephalitis are even more deadly. Review NEJM 351: 370, 2004.

      In fatal cases, there is widespread perivascular inflammation (usually lymphs; polys too in eastern equine encephalitis) and widespread necrosis of the brain. West Nile (USA 1999): Lancet 354: 1221, 1999, JAMA 283: 997, 2000, Science 287: 2129, 2000, Am. J. Clin. Path. 119: 749, 2003; JAMA 290: 511, 2003.

      The vast majority of West Nile infections never produce symptoms, but 20% of immunocompetent people do develop fever, and perhaps 1% develop nervous system syndromes. It is by far the most important epidemic encephalitis in North America; the molecular biology of why one person gets sick and another doesn't is just being worked out (J. Clin. Inv. 119: 3266, 2009). West Nile is now leaving people paralyzed, as with old-style polio. Brain damage, especially with uncontrollable anger outbursts, is also common after West Nile: JAMA 299: 2135, 2008 (sounds like Von Economo's all over again).

      * Louping ill, a sheep encephalitis transmitted by ticks to humans: J. Inf. 23: 241, 1991.

    ENCEPHALITIS AFTER CHILDHOOD EXANTHEMS (i.e., measles, mumps, chicken pox) is probably due in most cases to autoimmunity. Mumps and Epstein-Barr virus occasionally really do affect the brain.

    VON ECONOMO'S ENCEPHALITIS ("encephalitis lethargica", movie "Awakenings) coincided with the vicious influenza epidemic of 1918. It struck hardest at the basal ganglia and midbrain, with headache and somnolence.

      There were about 5 million encephalitis deaths overall, and many more millions of patients developed serious brain damage. (The influenza epidemic itself killed 20-40 million people.)

      The disease was (and is) variable, with extreme somnolence, agitation, dystonia, parkinsonism, stereotypy, echopraxoa-echolalia, and/or coprolalia.

      Some survivors of the 'flu epidemic developed post-encephalitic Parkinsonism, with neurofibrillary tangles in the dying cells of the substantia nigra. It was not uncommon for patients to become "living statues", fully aware but unable to move.

      Survivors who were able to move often exhibited hostility and aggression. Patients generally recognized these as unwanted and seemingly alien, and retained their intelligence and insight.

      The conventional wisdom that influenza was the direct cause is challenged by the failure to demonstrate influenza virus genes in any of the archived material (Virch. Arch. 442: 591, 2003). If the virus merely triggered autoimmunity, this isn't really surprising.

      An illness with similar histopathology (i.e., a lymphocytic-plasmacytic inflammation of the midbrain and basal ganglia; supposedly no neurofibrillary tangles though) seems to follow other infections on an autoimmune basis (Brain 127: 21, 2004; Movement Disorders 22: 2281, 2007; Internal Medicine 46: 307, 2007; big series from London Brain 127(1): 21, 2004). The tendency is now to regard "encephalitis lethargica" as a syndrome (post-streptococcal Eur. J. Ped. Neuro. 12: 505, 2008; West Nile Am. J. Med. 115: 252, 2003).

    HERPES SIMPLEX I encephalitis is fairly common in children and young adults, and produces severe, fulminant, necrotizing encephalitis, mostly of the temporal lobes. Pathologists examine brain biopsies for the characteristic intranuclear herpes inclusions (check the oligodendroglia).

      When "encephalitis" leaves its victims unable to form new memories, it's usually herpes simplex.

      The prognosis has improved since the introduction of anti-viral therapy.

{01335} herpes; look closely, the thing really is in the nucleus (the dark structure adjacent to the inclusion is the nucleolus)
{15473} herpes encephalitis, residual

Herpes encephalitis

WebPath Photo

Herpes simplex encephalitis

Yutaka Tsutsumi MD

    HERPES SIMPLEX II ENCEPHALITIS is why we deliver babies of mothers with HSV II by C-section. Around 50% of babies delivered normally during the primary infection are affected, often producing severe brain damage.

    SIMIAN B HERPES VIRUS MYELOENCEPHALITIS is a dreaded, fulminant complication of a macaque monkey bite. Like rabies, it follows the nerves to the brain, and requires post-exposure prophylaxis.

      * The virus, properly "cercopithecine herpes virus 1", causes cold sores in macaques. It is an emerging infectious disease and a serious problem as close to home as Puerto Rico. See Emerg. Inf. Dis. 10: 494, 2004.

    HERPES ZOSTER ENCEPHALITIS is usually a problem in the immunosuppressed, especially AIDS patients.

    POLIOMYELITIS is usually a mild viral summer gastroenteritis that sometimes produces a viral meningitis and/or attacks the lower motor neurons. Immunization has made the disease much less common in the developed countries, and its occurrence in recent memory among anti-immunization cultists (four among the Amish MMWR 46: 1194, 1997; Netherlands "orthodox reformed churches" Lancet 344: 665, 1994 has 68 sick, two dead; Minnesota Amish get vaccine-derived reverted polio J. Inf. Dis. 199: 391, 2009 -- nobody ended up paralyzed) or those who received weak vaccines (Lancet 335: 1192, 1990) proves it is still around. Christina's world
    Christina's World -- After Polio (?)

Poliomyelitis

Yutaka Tsutsumi MD

      There's still paralytic polio in the poor nations.

        There's no animal reservoir, so polio could be eliminated like smallpox was. There has been much talk about "global eradication of polio" since the late 1980's. In 1988 (during which 350,000 children worldwide were paralyzed from polio), the international community started dealing with polio systematically. By 1994, the Western Hemisphere was fully immunized and polio ceased to occur (a good thing that was 40 years overdue -- it happened mostly because of international philanthropy, not "good local government" in most of the Latin American nations). New cases come from the Old World kleptocracies (Br. Med. J. 313: 1412, 1996; how antibiotic injections, given in the poor nations for everything, turn non-paralytic polio into paralytic polio).

        The history of polio vaccines is interesting. The original Salk vaccine was a killed strain; the oral Sabin vaccine was a live attenuated strain. The live virus has a tendency, every once in a great while, to revert to the virulent form, and this can then spread if there isn't herd immunity (huge problem J. Inf. Dis. 197: 347 & 1427, 2008; horrible outbreak in Nigeria NEJM 362: 2360, 2010). In the US, we have herd immunity but want our vaccines ultra-safe, so we have returned to the killed form.


        Polio survivor, Angola
        In your writer's opinion, polio cannot possibly be eradicated in the foreseeable future. (NEJM agrees: 362: 2346, 2010; JAMA agrees 300: 839, 2008). Most people who are sick with, and spreading, the polio virus do not appear especially sick; in fact, if you've been immunized and met the polio virus, you often still spread it without any symptoms (J. Inf. Dis. 201: 1535, 2010). The virus is spread by water, and poor sanitation makes even one unfortunate person able to infect many, many others. Worldwide, TB, AIDS, and malaria are much greater health problems. And there are hundreds of stock specimens of the virus, and these are distributed in dozens of countries; surely some are in the hands of terrorists / rogue nations. For more, see Lancet 362: 909, 2003; Nat. Med. 9: 1225, 2003. Nigerian anti-Western politicians sponsor an anti-immunization disinformation campaign resulting in hundreds of sick children: NEJM 350: 645, 2004 (contains politically-correct euphemisms).

      * Japanese Encephalitis Virus is evidently now the major cause of an acute polio-like paralytic illness in Vietnam: Lancet 351: 1094, 1998.

    RABIES (* "lyssa", "hydrophobia"; Lancet 363: 959, 2004) results when a rhabdovirus follows the nerves up to the brain (1 mm/day or so) after the bite of a rabid animal (in the U.S. nowadays, most often a bat; remember cows, raccoons, and skunks; overseas remember monkeys and of course dogs).

      Rabies was the first disease to be controlled by the methods of science (Louis Pasteur and Emile Roux prevented the disease in litle Joseph Meister, who had been mauled by a rabid dog). Different animals harbor different strains. People with bat strains often do not remember a bite (Ann. Emerg. Med. 39: 528, 2002; the authors conclude that aerosol transmission is unlikely and that the bat bite went unnoticed). Hence a tendency to give rabies prophylaxis when a bat is found in a bedroom.

        The question, "What animal most often transmits rabies in the developed world?" cannot be answered. If you are bitten by a coyote that escapes, you will be immunized and no one will know whether the coyote was rabid. If you come down with rabies and have no known exposure, we must suppose it was a bat. And so forth.

        You are probably wise to be immunized against rabies if you plan to travel to a zone where it's rampant, especially India / Southeast Asia (Am. J. Trop. Med. 82: 1168, 2010).

      Rabies is among the most dreaded of diseases. It kills at least 60,000 people every year (J. Comm. Dis. 36: 195, 2004), and historically the disease has been incurable once the symptoms and signs appear. (In animals, the virus does not always produce disease.) I predicted the success of the elaborate protocol that includes antivirals and artificial coma therapy in these notes in 2003, and now it has worked.

        The first cure of human rabies: NEJM 352: 2508, 2005 (Wisconsin "Milwaukee Protocol; also Sci. Am. 296: 88, April 2007, by one of the team physicians.) Most subsequent attempts failed, in 2008 there were a few more recoveries reported worldwide.

      The distinctive "Negri bodies" are bullet-shaped intracytoplasmic inclusions in the neurons. The dramatic clinical syndrome includes headache, fever, irritability, paresthesias around the wound (helps make the diagnosis), excruciating spasms on movement or the thought of drinking ("hydrophobia"), and mania or stupor. Foaming at the mouth results from inabiity to swallow. Finally coma and death occur.

      * Rabies is most rampant in India, where stray dogs outnumber pet dogs 2:1 (J. Comm. Dis. 33: 245, 2001; strays infect both people and pets who then infect their owners), ordinary decent people do not have guns to protect themselves from rabid dogs, and the government's priorities do not include effective animal control or immunization (BMJ 331: 255 & 501, 2005). There are around 20,000 human rabies cases (all fatal; CMAJ 178: 564, 2008) in India alone every year, and 500,000 people need to be immunized; the typical Indian must pay 144 day's wages to be immunized (JAMA 1996; J. Trav. Med. 5: 30, 1998). India's "complementary and alternative practitioners" also think / pretend they can prevent rabies -- they can't (Int. J. Inf. Dis. 6: 236, 2002). The government of the "new India" is now wising up, and immunizing school children (Hum. Vacc. 4: 365, 2008).

      * By contrast, in 1994, the finding of one rabid kitten in a pet store (no clue how the kitten got infected) resulted in 665 people getting post-exposure prophylaxis, which was silly, painful, and expensive (Am. J. Pub. Health 86: 1149, 1996).

      Rabies transmission from an organ donor: Arch. Neuro. 62: 873, 2005; NEJM 352: 1103, 2005.

      * V-RG vaccine is a recombinant vaccinia virus bearing rabies antigens, which is distributed as food to wild animals. This is now widespread though low-profile, and it seems to work nicely (Vaccine 18: 3272, 2000).

      * DNA-based immunization is cheap and seems to work (Nat. Med. 4: 949, 1998) but isn't available for humans yet (updates Vaccine 25: 4020, 2007; Vaccine 26: 6936, 2008; Vaccine 27: 2128, 2009). The replication-deficient rabies virus-based vaccines: J. Inf. Dis. 200: 1251, 2009.

    The disease appears to remain latent within feral carnivores, and can be activated by stress (Nature 359: 277, 1992). "One of the local wolves went rabid."

{01337} Negri body Old Yeller

    CYTOMEGALOVIRUS ENCEPHALITIS ("ventriculoencephalitis") causes necrosis and (typically) dystrophic calcification of the brain in children infected before birth. The ependymal cells / periventricular region is selectively affected. Radiologic correlation Radiology 230: 529, 2004. The pathology in acquired CMV encephalitis (as in AIDS) is similar (Neurology 55: 1910, 2000) -- you'll make the call on PCR of the spinal fluid.

CMV encephalitis in AIDS

Yutaka Tsutsumi MD

    AIDS ENCEPHALOPATHY ("AIDS dementia complex") affects the majority of HIV-positive victims during the course of their illness. Patients may have acute viral meningitis shortly after meeting the virus, a peripheral neuropathy, a "vacuolar myelopathy" (very common; look at the dorsal columns), and subacute encephalitis. In the latter, groups of macrophages, lymphocytes, and multinucleated giant cells (fused macrophages/microglia) cluster in the white matter, with loss of surrounding myelin.

      The majority of AIDS patients become demented, at least to some degree. We do not really know everything that's going on, or all the morphologic correlates. The clinical syndromes (motor, behavioral, mixed) are still being sorted out (Neurology 69: 1789, 2007).

      Young children with HIV are prone to calcification of the vessels and white matter deep in the brain. Nobody knows why.

{37378} HIV giant-cell encephalitis

HIV-induced encephalopathy

Yutaka Tsutsumi MD

    HTLV-I ENCEPHALOPATHY encephalomyelopathy (tropical spastic paresis) is well-known, especially in the Caribbean and Brazil (Neurology 48: 13, 1997). The virus is now established as the (probably only) etiologic agent. This may be an example of molecular mimicry (Nat. Med. 8: 509, 2002; in 2006 still only one group is writing about this). Many (perhaps most) people infected with HTLV-I have some symptoms (leg weakness / hyperreflexia / bladder problems), but the clinical picture is highly variable (Neurology 61: 1588, 2003). There are likely to be many lymphocytes in affected areas.

HTLV-1 myelopathy

Yutaka Tsutsumi MD

SLOW VIRUS INFECTIONS: Long incubation period (years), long relentless disease (months or years)

    SUBACURE SCLEROSING PANENCEPHALITIS ("SSPE") is caused by measles virus (acting as a slow virus; victims had previous had measles). Despite "pan-", the white matter is most severely affected. Oligodendroglia, and to a lesser extent neurons, are destroyed, and measles (one of many cases of "Cowdry A") inclusions are seen in the nuclei of sick cells. Dementia and motor problems occur, with death following over a few years.

      You'll make the diagnosis in life by the clinical picture and by finding very high titers of anti-measles antibody in the spinal fluid.

      People who have received the live vaccine and do not remember clinical measles have occasionally come down with SSPE, but the rate is less than 1/10 of that for the natural infection (about 1 in 100,000). Most likely they had measles before, or in spite of, the immunization (Epid. Inf. 131: 887, 2003). In any case, the measles virus from these people is the wild strain, not the vaccine strain (Neurology 58: 1568, 2002; Acta Paed. 93: 1251, 2007; BMC Pediatrics 5: 47, 2007).

Subacute sclerosing panencephalitis
Measles
Yutaka Tsutsumi MD

    PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY ("PML") is an opportunistic infection (AIDS, cancer) by JC (John Cunningham) papovavirus (less often, SV-40). It affects oligodendroglia, blocking production of myelin basic protein and causing apoptosis (Arch. Neuro. 59: 1930, 2002), and produces soft, gray patches, especially around the gray-white junction. Affected oligodendroglia nuclei contain distinctive inclusions made of virus crystals, while nearby astrocytes (which the virus has also infected) acquire bizarre, very large nuclei ("Alzheimer's type I glia", also seen sometimes in SSPE).

{31956} progressive multifocal leukoencephalopathy; Alzheimer I bizarre large glial nucleus
{31957} progressive multifocal leukoencephalopathy; this shows the inclusion bodies better
{01744} PML inclusions, schematic diagram

JC virus
Progressive multifocal leukoencephalopathy
Yutaka Tsutsumi MD

PML
Great scans and photos
Pittsburgh Pathology Cases

Progressive Multifocal Leukoencephalopathy
Pittsburgh Illustrated Case

    * "Progressive rubella panencephalitis" was a rare probable re-activation of the virus in children with congenital rubella who went on to develop inflammation of the brain and die (NEJM 292: 990, 1975.) Depending on the future successes of anti-immunization militants, you may see rubella with all its grisly after-effects once again.

    Somebody might still try to tell you that the spongiform encephalopathies are "slow virus infections". Given present knowledge, this is simply ignorant.

SPONGIFORM ENCEPHALOPATHIES ("unconventional agent encephalopathies"; a better name today would be "prion dementias"; some people call these "transmissible amyloidosis"; others group them with the proteinopathies as "diseases of protein misfolding"). Update Arch. Neuro. 62: 545, 2005; Lancet 363: 51, 2004.

Creuzfeldt-Jakob's disease

Yutaka Tsutsumi MD

Gerstmann-Straussler disease

Yutaka Tsutsumi MD

Prions
Pittsburgh Pathology Cases

Spongiform encephalopathy
WebPath Case of the Week

Prion disease

WebPath Photo

Prion disease

WebPath Photo

Prion disease

WebPath Photo

Prion disease

WebPath Photo

Prion disease
Lots of amyloid ("kuru plaques")
WebPath Photo

    These infectious disorders are caused by agents that, to scientists before the 1990's, seemed to break the rules of basic biology. It has been clear since the 1970's that they lack nucleic acid (Nature 349: 569, 1991). They are designated PRIONS (PR for "protein", I for "infection", "-on" to finish it up.) Nobel Prize 1997, Stanley Prusiner for figuring out how they work.

      The most efficient means of transmission is direct inoculation of infectious nervous system material. Unfortunately, it takes autoclaving, hypochlorite or phenol to render the material non-infectious.

      By definition, prions are protein-containing infectious particles that keep their infectivity after being subjected to procedures that specifically destroy nucleic acids. A portion of the prion protein is known to be a neurotoxin (Nature 362: 543, 1993).

    By the late 1990's, the mystery was solved. All known prions are altered conformational states of "prion protein" (PrP; PRNP; Science 233: 364, 1986), a normal membrane glycoprotein coded in the mammalian genome (* human chromosome 20), and well-conserved over evolution, has its gene transcribed (but does not accumulate) in health (Neurology 40: 518, 1990), and is not homologous to other known proteins. No other components have been identified to date. THE ALTERED PrP CATALYZES THE TRANSFORMATION OF NORMAL PrP MOLECULES INTO MORE PRIONS.

      The infectious particles are designated PrPSc (for scrapie; protease-resistant) and the healthy cellular form itself is PrPC (for Creutzfeldt-Jakob disease; protease-sensitive). The exact sequences change when the infections are passed from one species to another, confirming that the new particles are coded by the host genome.

      PrPSc transforms PrP to PrPSc by altering its physical conformation (Nature 349: 569, 1991; how Proc. Nat. Acad. Sci. 90: 10962, 1993).

    A variety of human and animal syndromes are all really variations on the same theme.

      SCRAPIE causes sheep to scrape themselves against fence posts, then become demented and die. (* Don't confuse scrapie with VISNA, which is caused by a retrovirus.)

      TRANSMISSIBLE MINK ENCEPHALOPATHY was transmitted to minks by feeding them dead sheep that had scrapie.

      CREUTZFELDT-JAKOB DISEASE (CJ disease or JC disease; the former is preferred now because this Creutzfeldt described it first and the disease has nothing to do with JC virus) is a relatively uncommon (annual incidence 1/million in most societies), dementing disorder that usually strikes between ages 40 and 60, no sex predominance. Motor symptoms (pyramidal, extrapyramidal, myoclonic, and/or cerebellar) and behavioral aberrations may be noted. The EEG is distinctive and establishes the diagnosis. The disease is relentless and untreatable, and death results within a year or so.

        Usually sporadic, the disease has also followed exposure to corneal transplants, surgical instruments (Lancet 1: 478, 1977), pituitary extract (NEJM 313: 731 & 734, 1985; Lancet 337: 1441, 1991; of the many who were exposed, those getting sick had a mutant PrP), and formalin-fixed, paraffin-embedded brain (NEJM 318: 853 & 854, 1988, well, maybe). Pathologists treat this agent with great respect.

        Early diagnosis of spongiform encephalopathy can occasionally be made in humans and animals by examining the tonsils. In humans with bovine spongiform encephalopathy it is supposedly always present; otherwise the yield is low. See Nature 381: 563, 1996; update Lancet 364: 1260, 2004. Unfortunately, this doesn't work as a way of screening for other prion diseases.

        Clinical reviews: Br. Med. J. 300: 817, 1990; South. Med. J. 83: 141, 1990 (physician's duty; the disease doesn't seem to be catching from patients); Brain 113: 121, 1990 (electron micrographs). Genes for PrP seem to correlate with susceptibility: Nature 352: 340, 1991; as do other genes modifying the course of the infection (Nat. Genet. 18: 118, 1998).

        * Congo red was tried as a treatment for prion disease; it failed miserably.

        * Amyloid ligands to distinguish prion disease from atypical Alzheimer's on scans: Neurology 69: 283, 2007.

        Creutzfeldt-Jacob
        Pittsburgh Illustrated Case

Knowledge makes you vain, education makes you humble.

              -- Hans G. Creutzfeldt (worth repeating)

      BOVINE SPONGIFORM ENCEPHALOPATHY ("mad cow disease") was transmitted to British cattle by feeding them meal that included sheep that had died of scrapie. Thanks to an altered method of preparing the feed, prions were no longer inactivated. That there was an epidemic was obvious by 1990 (Nature 343: 193 & 196, 1990; Nature 344: 297, 1990; molecular biology J. Inf. Dis. 167: 602, 1993).

        About 170,000 cattle died of the disease. The British had also been using very, very poor slaughterhouse practices, with brain mixing with the meat. The "mad cow" flap resurfaced in 1996, with the claim (Lancet April 6, 1996, most of the issue) that a new strain of Creutzfeldt-Jacob disease, with early onset, more psychiatric changes, less myoclonus, and lots of amyloid, had perhaps resulted from the abundance of prions in beef.

        Later that year, Nature (383: 685, 1996) demonstrated that these patients, as well as the cows, had a prion with some different physico-chemical properties, i.e., a differently-twisted prion that autocatalyzes normal PrP true-to-form. The beef strain is now called "nvCJD" ("new variant"), or Will-Ironside Syndrome (Lancet 352: 252, 1998).\ The patients live longer, and the abnormal behavior is more prominent than the dementia.

        In human vCJD, a mutation (methionine at codon 129) in the PNRP gene is required for susceptibility (Lancet 364: 527, 2004).

        First apparent transmission of vCJD by blood transfusion: Br. Med. J. 328: 118, 2004.

        * Rocky Mountain deer and elk have an epidemic prion disease. Americans are eating them. Is anybody getting sick? Maybe, but probably not (Arch. Neuro. 58: 1673, 2001.) Nobody even talks about this. Compare this indifference to the horrible flaps whenever anyone suspects a single American cow might have "mad cow" disease.

      KURU affected cannibals in New Guinea, and victims appeared to be those persons who rubbed raw brains of previous victims over their own bodies. Motor problems and dementia led to death within months to years. It is Creutzfeldt-Jakob disease, transmitted in an exotic ethnic group. You will enjoy reading Am. J. Med. 26: 442, 1959 and Science 197: 943, 1977.

      HEREDITARY CREUTZFELDT-JACOB DISEASE (gCJD) features any of three mutations in PrP (* E200K, D178N, or V210I). These are transmitted as dominant genes and produce proteins that have a much greater tendency to misfold. Sooner or later, the cascade starts by itself.

        The array of PrP mutations: Neurology 42: 422, 1992; Brain 115: 675, 1992; and how different mutations affect prion distribution at autopsy: Am. J. Path. 141: 271, 1992.

        * CJ disease in Libyan Jews (NEJM 324: 1091, 1991) turned out to be gCJD (E200K; Medicine 76: 227, 1997). This exonerated the ethnic custom of eating raw sheep brains and eyeballs.

      GERSTMANN-STRÄUSSLER DISEASE is another hereditary prion disease. These patients have a different mutation in PrP (* P102L or A117V). Transgenic mice with Gerstmann-Sträussler: Science 250: 1587, 1990; the disease has been transmitted FROM these mice, strongly confirming what we were learning about CJ disease in general: Science 251: 1023, 1991.

      Transgenic mice with no PrP seem to be okay mice (Nature 356: 577, 1992, except that they get the staggers late in life: Nature 380: 528, 1996) and of course they are immune to prion disease (Proc. Nat. Acad. Sci. 90: 10608, 1993).

      * A different prion-related disease, FATAL FAMILIAL INSOMNIA, as bad as it sounds, involves rapid destruction of the thalamic AV and DM nuclei without spongiform change. The disease is autosomal dominant and involves a different substituted PrP allele (178 aspartate-->asparagine) plus methionine at 192. Read all about it: NEJM 326: 444, 1992, Neurology 42: 669 & 1859, 1992, further complexities Science 258: 806, 1992; review Proc. Nat. Acad. Sci. 91: 2839, 1994; Neurology 49: 552, 1997; produces standard-brand prion disease when transmitted to mice Nautre 377: 65, 1995.

    In spongiform change, the neuropil appears vacuolated ("spongiform changes"); the vacuoles are in the cell processes and perikaryons. At autopsy of victims of the spongiform encephalopathies, the neurons are mostly gone, but there is a corresponding tremendous astrocytosis, so brains may not appear atrophic. Pathology: Neurology 39: 1337, 1989.

      "Kuru plaques", made of beta-pleated ("amyloid") PrP, affect most patients with Kuru and * GS disease and around 10% of patients with Creutzfeldt-Jakob disease. Kuru plaque formers have leucine at codon 102 of PrP.

      * The differences in clinical pictures from patient to patient correlates best with which thalamic cells are most severely damaged: Brain 125: 2558, 2002.

    * Prions probably have nothing to do with diseases except for the spongiform encephalopathies (Lancet 341: 127, 1993).

    If tonsillar biopsy is negative (as it usually is in non-mad-cow prion disease in humans), the diagnosis requires correlation of clinical, imaging, and brain biopsy/autopsy findings. Suggested lab tests on CSF have proved unreliable at best (Arch. Neuro 60: 813, 2003). Everybody would like a way to establish the diagnosis without having to resort to brain biopsy. Prions are likely to be present in other tissues (NEJM 349: 1812, 2003) including peripheral nerves (Arch. Neuro. 61: 747, 2004), but so far nothing is reliable.

    * An antibody that clears prions, in culture and perhaps in vivo: Nature 412: 739, 2001.

    * Dr. Creutzfeldt managed to save all of his neuropsych patients, and some people in concentration camps, from the Nazis.

OTHER BRAIN INFECTIONS

Aspergillus

WebPath Photo

    You are already acquainted with aspergillus and mucormycosis, which invade blood vessels and can infarct the brain. Candida (the most common fungal brain pathogen) and cryptococcus can produce brain infections by spreading from fungal meningitis; Candida is likely to present microabscesses.

    ROCKY MOUNTAIN SPOTTED FEVER and TYPHUS affect primarily the endothelial cells; they may produce the familiar glial nodules ("typhus nodules") in the brain. Patients are likely to have severe headache.

    ACANTHAMOEBA is an opportunist that often produces a granulomatous response. NAEGLERIA, acquired by healthy people who swim in stagnant ponds, enters the CSF via the nose, and causes necrosis of the olfactory bulbs and nearby frontal and temporal lobes. BALAMUTHIA is yet another amoeba, larger than the others; the newest amoeba is Sappinia pedata (J. Inf. Dis. 1139: 2009. Update on pathology of amoebas in the brain: Mod. Path. 28: 1230, 2007.

    * Expect poison from standing water. -- William Blake

{08419} acanthamoeba, trust me
{08278} naegleria, trust me

Acanthamoeba
CDC
Wikimedia Commons

Naegleria meningoencephalitis

Yutaka Tsutsumi MD

Acanthamoeba of the brain
Great photos
Pittsburgh Pathology Cases

Acanthameba meningoencephalitis

Yutaka Tsutsumi MD

Amoebas in the brain
Fluorescence
Wikimedia Commons

    TOXOPLASMOSIS causes brain damage similar to that seen with CMV in the fetus (including calcifications), or a necrotizing meningoencephalitis or discrete mass in AIDS patients.

      * It's well-known that toxoplasmosis affects the brains of mice so that they will seek out rather than run from cats. Of course this is how the disease cycles. A human counterpart may be the discover that, at least in Istanbul, a very large percentage of traffic accident victims have toxoplasmosis (For. Sci. Int. 187: 103, 2009).

Toxoplasma meningitis

Yutaka Tsutsumi MD

Toxoplasma encephalitis in AIDS

Yutaka Tsutsumi MD

{15472} toxoplasmosis of the brain in AIDS
{53733} brain damage from toxoplasmosis before birth
{32317} cat, trust me

    CYSTICERCOSIS is the larval stage of the pig tapeworm ("Taenia solium") in the brain. Single worms can serve as foci for seizures, a few can obstruct the flow of CSF, or masses of larvae can fill the ventricles ("racemose form").

      * It affected the ancient Egyptians (Am. J. Trop. Med. 74: 598, 2006).

Cysticercosis of the brain

Yutaka Tsutsumi MD

Cysticercosis
Pittsburgh Pathology Cases

Neurocysticercosis
Spectacular x-ray
Brazilian Medical Students

    CEREBRAL MALARIA, once attributed to immune complex deposition in blood vessels, is now clearly caused by plugging of the vessels by infected red cells that stick to each other and to the endothelium (Nat. Med. 10: 143, 2004). This is obvious from the morphology anyway.

Cerebral malaria

Yutaka Tsutsumi MD

    SLEEPING SICKNESS (African trypanosomiasis) is a worsening health problem in sub-Saharan Africa (Lancet 375: 148, 2010; Neurology 66: 1094, 2006; J. Clin. Inv. 113: 496, 2004).

      You are already familiar with the tsetse fly. There are perhaps 300,000 new cases yearly.

      The histopathology is distinctive.

      • There is a CNS vasculitis with plasma cells, macrophages, and lymphocytes surrounding the vessels.
      • Many of the IgM plasma cells contain many Russell bodies.
      • There is likely to be fibrinoid necrosis of the vessels.
      • Around the inflamed vessels, the astrocytes are strikingly enlarged.

      The familiar trypanosomes are seldom seen in the blood. The diagnosis is made on serology; if positive, patients get a lumbar puncture to see whether CNS involvement has begun. If there is elevated protein / elevated WBC / anti-trypanosomal IgM (all can be done in the field), they are treated with trivalent arsenicals, the only effective remedy for the brain disease. The arsenical treatment itself carries a mortality rate of 5%, though of course the untreated disease is always fatal.

        As a physician, you must warn travellers. A tourist dies (sad story, but great photos): Neurology 66: 1094, 2006.

    ONCHOCERCIASIS causes blindness and epidemic epilepsy in much of sub-Saharan Africa: Lancet 372: 1721, 2008.

HEADACHE

    If it's not the person's usual headache, it is meningitis, herpes encephalitis, or a leaking berry aneurysm until proved otherwise.

    Anything that puts a stretch on the scalp or the dura will make the head hurt. But pain can also be generated within the brain itself.

    The most common cause of headache in the U.S. is probably CAFFEINE WITHDRAWAL (i.e., less coffee today than yesterday).

      * This fact explains:

      • why savvy surgeons tell patients to drink no coffee during the week before surgery, so that on the morning of surgery (or after surgery), the patient had no headache;
      • why "Anacin", an old overpriced aspirin preparation containing a bit of caffeine, and the old irrational combination of aspirin, phenacetin, and caffeine "worked so well for headache / all forms of pain";
      • why "headaches result from stress" (i.e., times when people drink more coffee to push themselves) "and muscle spasm" (i.e., reflex spasm of the occipital muscles to centrally-generated pain.)

      The scientific community noticed the caffeine withdrawal syndrome during the 1980's. The headache, tiredness, irritability, dysphoria, and sometimes upset stomach are common and, fortunately, mild. See Br. Med. J. 300: 1558, 1990; Am. J. Psych. 149: 33, 1992; NEJM 327: 1109, 1992; Mayo Clin. Proc. 68: 842, 1993. I hope this does not surprise you.

    MIGRAINE is a centrally-generated pain syndrome, and the old story about "vasoconstriction followed by reactive vasodilatation" was silly (Neurology 42(3S2): 6, 1992), as any thinking person who's had a throbbing headache realizes.

      The process is a vicious cycle between the spinal nucleus of V and the cerebral vessels, with sensory afferent stimulation (especially sudden changes in the internal or external environment) making the cycle worse (migraine patients seek out a dark silent room; the migraine story Neurology 43(6S3): S11, 1993).

      Different people have different migraine thresholds (Arch. Neur. 49: 914, 1992). Ordinarily, the pain and nausea are disabling, but the attacks end almost as abruptly as they began.

      In exceptional cases, the vessels can, indeed, spazz shut and produce a stroke (well, maybe; if it happens, it must be very uncommon BMJ 330: 63, 2005). When migraine is a problem in middle-age, infarcts are more likely to be found on scan, but curiously these are in the cerebellum (! JAMA 301: 2563, 2009).

      The disturbance in chemistry and physiology is systemic (Neurology 43(6S3): S16 & S43, 1993) and mysterious; the new crop of drugs react with the serotonin receptors (aborter drugs like sumatriptan activate 5HT1 receptors on vessels, preventive medicines activate 5HT2 receptors in the brain substance itself; these also seem to be good for "muscle spasm tension headaches"). All about treating migraine: Am. Fam. Phys. 49: 33, 1994. One remedy is lignocaine onto the sphenopalatine ganglion.

    CLUSTER HEADACHES (* Horton's headache) are usually unilateral and feature tearing of the eye and dropping from the nostril on the same side. Review Lancet 366: 843, 2005.

      The many novel therapies for this often-devastating illness now include occipital nerve stimulation -- osteopathic med students take note!

      Both migraine and cluster patients have been reported to have various abnormalities of gray matter (early work Nat. Med. 5: 836, 1999.) Whether these are the cause of the pain or the result is still speculative (Brain 132: 1419, 2009).

    UNCORRECTED REFRACTIVE ERROR is another important cause of headache. Humanitarians: Note that these "trivial" conditions can ruin the quality of a person's life, though they are not part of the classic content of pathology.

    "Valsalva headache" following straining at stool / exertion / coughing probably has an interesting correlate (something somewhere in the dura must be getting stretched), but so far it has eluded us. One group actually looked on MRI and found nothing (Headache 36: 251, 2005).

    HANGOVER requires no description here. Ask a pharmacologist about withdrawal, fusil oils, etc., etc.

    We'll leave you to finish the list of causes of headache. They include all of the processes on this handout that involve deformation of the cranial contents. The worst headache is supposed to be ruptured berry aneurysm. Please don't send meningitis, herpes encephalitis, or berry aneurysm patients home on painkillers. When in doubt, scan and/or tap. A history may tip you off to a very small longstanding spinal fluid leak. Despite what was recently dogma, your lecturer does not believe that "depression" is an adequate explanation for headache. Try getting "headache" patients off daily analgesics and coffee (South. Med. J. 86: 1202, 1993).

CNS DEGENERATIVE DISEASE

Neurodegenerative Disease
Click to see the images
Duke

Pathology of CNS Degenerative Disease
WebPath Tutorial

Neurodegenerative Diseases
Great pictures in a clickable handout
Duke

INTRODUCTION

    The "degenerative diseases of the CNS" are a family of disorders, most involving accumulations of altered forms of our own proteins, in which neurons at certain locations are selectively lost and symptoms eventually result.

      Almost all are inexorably progressive to profound disability and death.

      They range fron simple Mendelian disorders (for example, Huntington's and many others) through disorders that are probably polygenic and variably expressed (for example, Alzheimer's and schizophrenia) to "disorders in which heredity plays no part" (for example, common parkinsonism).

      The simplest "animal model" for these diseases is a dominant gene for late-onset degeneration of a few neurons in the roundworm; the effects of this gene are modified by a host of other genes (Nature 345: 410, 1990).

      Watch for these to be renamed "the proteinopathies" soon.

    DEMENTIA: Sustained permanent decrease in several dimensions of intellectual function, so as to interfere in normal social or economic activity.

      * Clinical lore, and perhaps helpful: In the cortical dementias (Alzheimer's, Pick's, Lewy body, post-herpetic), new memories don't get laid down at all, i.e., no amount of prompting can get the morning's events remembered. In the subcortical dementias (PSP, Parkinson's, Huntington's, Wilson's, multi-mini-infarct), the new memories are there, but harder to access, and prompting can work. Let me know if this turns out to be true in your ward experience.

    AMENTIA: Mental retardation (misnomer)

    OBTUNDED: Less responsive than normal, especially to pain

    DELIRIUM: Reversible impairment of mental functioning, typically with some degree of disorientation, usually without permanent abnormalities, usually with some agitation.

    * ABIOTROPHY: Neurons "just decide to die". This word is passing out of use as we discover the real causes of these diseases. "Jargon is not insight."

    The differential diagnosis of dementia in the older patient is a long one. Think of:


      Cortical degenerations

        Alzheimer's
        The frontotemporal dementias (Pick's & its large family)
        Lewy body dementia
        Argyrophilic grain disease
        Schizophrenia (path update: Am. J. Psych. 160: 867, 2003)
        * Mild fragile X
        Some others

      Subcortical degenerations

        Parkinsonism / Parkinsonism plus
        Huntington's chorea
        "Normal pressure hydrocephalus" (still poorly understood)
        Neglected Wilson's
        Corticobasal degeneration
        * Bilateral symmetrical degeneration of thalamus and a host of other extremely rare illnesses that your neuroradiologist might perhaps be able to diagnose

      Other CNS infections / inflammations

        Cryptococcosis
        Lyme disease (don't miss this one)
        Creutzfeldt-Jacob
        Neurosyphilis (still with us)
        TB
        Lupus
        CNS sarcoid (* don't miss this one; it tends to involve the meninges around the hypothalamus and grow down the Virchow-Robin spaces)
        Paraneoplastic encephalopathies (be alert to this)
        Whipple's disease (don't miss this one, either)

      Nutritional disease

        Subacute combined degeneration (i.e., vitamin B12 deficiency)
        Folic acid deficiency (maybe)
        Magnesium deficiency (don't miss this one; no one really knows the best way to check for it, either)
        Wernicke-Korsakoff

      Vascular CNS disease (very common: NEJM 328: 153, 1993)

        Atherosclerotic arterial stenosis
        Binswanger's hypertensive damage
        Multi-infarct dementia
        Hashimoto's encephalopathy (vasculitis, don't miss this one)
        Lupus
        * CADASIL and (unlikely) Moyamoya
        * Sneddon's syndrome (livido reticularis followed by small strokes, often with anticardiolipin / antiphospholipid antibodies: Mayo Clin. Proc. 74: 57, 1999; Neurology 60: 1181, 2003)

      Endocrine disease

        Hypothyroidism
        Hyperthyroidism
        Addisonism
        Hypoglycemia

      Neoplastic disease

        Glioblastoma
        Meningioma
        Metastatic disease
        Remote effects of cancer

      Trauma

        Chronic subdural hematoma
        Diffuse axonal injury

      Psychiatric/functional disease

        Depression
        No glasses / needs cataract surgery
        No hearing aid / needs earwax removed

      Overlooked medical disease

        Bad kidneys
        Bad liver
        Blue bloater
        Sleep apnea (Geriatrics 45(6): 16, 1990)
        Parathyroid adenoma
        Porphyria

      Poisoning


        Lead
        Mercury
        Other industrial poisons

        Pfiesteria piscicida, the dinoflagellate from Chesapeake Bay, and the coasts of Virginia and North Carolina, due to contamination by pig runoff, is another neurotoxin to watch. J. Tox. Env. Health 46: 501, 1997; Lancet 352 532, 1998. Anecdotal reports from fisherfolk and from two technicians at Duke who still complain of memory problems are alarming. It's now called "estuary syndrome". The toxin, long-unidentified and doubted, now is reported as a curious metal complex (Env. Sci. Tech. 41: 1166, 2007. Stay tuned.

        Certain cancer chemotherapeutic protocols produce serious brain damage (for only one example, which suggests how badly this problem has been overlooked, see Neurology 59: 48, 2002; more Neurology 62: 548, 2004).


      Iatrogenic disease

        Anti-hypertensive medications
        Anti-convulsant medications
        Sedatives
        Too much digitalis
        Polypharmacy in general


    * Here's an old NIH Consensus Conference's list of tests for the demented (Med. Clin. N.A. 77: 215, 1993):


      History and physical exam
      Medication history
      Neuro and psych exam
      CBC, 'lytes, chem profile, UA, syphilis serology
      CXR, EKG
      Serum B12 and folate; consider also homocysteine and methylmalonate
      CT of the head
      Thyroid panel

      I would have added an anti-nuclear antibody, an anti-Ro, a serum magnesium (!), and a Lyme serology, plus lead and mercury screens for those that might have been exposed. Anti-microsomal antibody for anybody with a goiter (Hashimoto's encephalopathy does not always feature hypothyroidism.)

      Of course, down the road (especially if Alzheimer's become treatable) we may have a host of assays on spinal fluid (Alzheimer's proteins Arch. Neuro. 66: 382, 2009) and/or be making extensive use of PET scans with specific markers to light up specific proteinopathies. Stay tuned.

    Brain biopsy for slow dementia: One center's experience: Arch. Neurol. 49: 28, 1992. Another's: Brain 128: 2016, 2005 (just over half are diagnostic; out of 90, one curable disease -- Whipple's -- was found). Still not a routine procedure! Brain biopsy for more rapid dementia seems much more worthwhile, with lymphomas and prion disease found most often (J. Neurosurg. 106: 72, 2007), and no one questions that brain biopsy in known HIV infection or suspected non-lymphomatous tumor can often be essential.

    * UCLA autopsy series for causes of dementia: Arch. Path. Lab. Med. 128: 32, 2004. Alzheimer's is most common, with vascular dementias second, and Lewy body dementia (6%), normal-pressure hydrocephalus, PSP, and Pick's (and variants; 4%) all common as well.

ALZHEIMER'S DISEASE ("pre-senile dementia", "senile dementia", "old timer's disease", "brain failure", etc.; "a primer for practicing pathologists": Arch. Path. Lab. Med. 117: 132, 1993)

Alzheimer's with amyloid
Brazil Pathology Cases
In Portuguese

Alzheimer's disease
Photo essay
U. of Utah

    This very common dementing disease affects several million Americans. It becomes more common with advancing age, and will be an even more serious a problem as the numbers of elderly increase.

      If you control for how old people are, Alzheimer's is about equally common everywhere in the world.

      The disease seldom begins under age 50, except in Down's syndrome survivors, who all get it in their thirties or thereabouts (N.Y. State Med. J. 90: 64, 1990). Estimates of its frequency vary widely, but around 5% of people over 65 are affected, and 20% of people over 80 are affected. There is no sex predominance.

      The familial forms of Alzheimer's, which accounts for around 5-20% of cases, are mostly autosomal dominant. There are now several different loci known. See below.

      We no longer distinguish between "pre-senile dementia" (Alzheimer's before age 65) and "senile dementia" (Alzheimer's after 65; formerly only "pre-senile dementia" was dignified with the Alzheimer's label, though the pathology and symptomatology are identical.)

      Almost all very-old folks have some Alzheimer's type changes in the brain, but these correlate with dementia much more strongly at age 75 than at age 95 (NEJM 360: 2302, 2009. No one understands why.

      More evidence that the "plaques and tangles" aren't central to the dementia: Folks with lots of "Alzheimer's pathology" at autopsy but whose brain weights and hippocampal volumes were still fairly large showed little or no dementia (Neurology 72: 354, 2009).

    You will learn plenty about Alzheimer's disease during your medical education. Here, we'll focus on the pathology.

      The gross pathology is that of diffuse cortical atrophy, with widening of the sulci, narrowing of the gyri, and hydrocephalus ex vacuo.

        Once Alzheimer's disease declares itself, the worst-affected areas of cortex can shrink by around 15% per year (!! Lancet 343: 829, 1994).

{34478} brain atrophy

Brain atrophy

WebPath Photo

Brain atrophy.
Alzheimer's.
WebPath Photo

Alzheimer's disease
Silver stain
KU Collection

Brain atrophy

WebPath Photo

Brain atrophy
Hydrocephalus ex vacuo
WebPath Photo

      The microscopic pathology shows several distinctive features:

        NEUROFIBRILLARY TANGLES are beta-pleated from over-phosphorylated tau protein, in the form of twisted paired helices ("curly fibers"), within neurons. They stain best with silver (*Bielschowsky).

{26762} neurofibrillary tangles

Neurofibrillary tangle

WebPath Photo

Neurofibrillary tangles
Silver stain
WebPath Photo

          A major component of these tangles tau protein, a microtubule element (Proc. Nat. Acad. Sci. 88: 8910, 1991; Am. J. Path. 140: 277, 1992). Ubiquitin is added as they grow; you may also find some Aβ (see below).

          Neurofibrillary tangles in the cortex-only strongly suggest Alzheimer's or chronic traumatic encephalopathy. You can see them elsewhere in post-encephalitic parkinsonism, progressive supranuclear palsy, corticobasal degeneration, ALS-dementia complex of Guam, and a few others.

          Counting neurofibrillary tangles in various areas gives the "Braak stage" for Alzheimer's, which its developers in the late 1980's felt was the best correlate with dementia (i.e., tangles are more important than plaques). This has some support (Neurology 62: 428, 2004).

        SENILE PLAQUES ("neuritic plaques") are focal abnormalities in the cortex (check the hippocampus), 20-150 microns across, consisting of abnormal, tau-protein laden nerve processes, microglial cells, and turned-on astrocytes, in the later stages surrounding an amyloid core made of Aβ and apo-E (future pathologists read Am. J. Path. 137: 1383, 1990). Unless there is an amyloid core, the fibers are not disrupted or disorganized. The neuritic processes contain tau isoforms like those in neurofibrillary tangles.

          As easy as it would be to think that the physical disruption by the plaques is central to the brain failure, the real lesion is probably still something more sutble at the molecular level. In some of the mouse models, plaques are few but dementia is severe. In 2005, I reported, "We will not know whether the amyloid accumulation is the true cause of the dementia until the amyloid-removing therapies start working (J. Clin. Inv. 115: 1121, 2005)." Now the verdict seems to be in -- the plaques are NOT central to brain failure. See below.

          * The amyloid cores were originally described as containing some aluminum silicate. I have taught for 30 years that the aluminum silicate in the old studies got there as a result of binding during the tissue processing. I believe I was right. Aluminum caused neurotoxicity in "dialysis dementia" decades ago, but the neuropathology is completely different (Neuropathology 22: 206, 2002), and heavily-aluminum-exposured, relatively young brains do not exhibit more Alzheimer changes (proliferation of astrocytes and microglia in the cortex, basal ganglia, and thalamus; no NFT's or plaques -- Acta Neuropath. 101: 211, 2001). Further, a host of studies (summary CMAJ 162: 65, 2000) show that the brains, the tangles, and the plaques do not contain excess aluminum after all. Despite decades of trying, no "environmentalists" have been able to show an obvious risk from drinking water or dietary aluminum concentrations. Results of studies on aluminum concentration in drinking water and Alzheimer rates are mixed, and in any case drinking water contributes only a small amount of total aluminum in the diet (Brain Res. Bull. 55: 187, 2001). And having worked in an aluminum factory clearly does NOT put you at greater risk (Br. J. Psych. 168: 244, 1996). The other 1990's hoopla, about silicate in the drinking water causing Alzheimer's, crashed and burned when a retrospective French study found that the more silica in the drinking water, the less Alzheimer's (Am. J. Clin. Nutr. 81: 897, 2005).

{01339} senile plaques
{01341} senile plaques, silver stain
{01342} senile plaques, immunoperoxidase stain for amyloid

Senile plaques
Silver stain
WebPath Photo

Senile plaques
Silver stain
WebPath Photo

Alzheimer's disease
Amyloid
WebPath Photo

Alzheimer's disease
Senile plaque -- silver stain
WebPath Photo

Alzheimer's
Senile plaques
Wikimedia Commons

        Lots of older people have a few plaques in the hippocampus. More than a very few plaques in the neocortex means Alzheimer's (Arch. Neuro. 50: 349, 1993).

        Of course, dendrites and their complex patterns are also greatly diminished in Alzheimer's: Am. J. Path. 163: 1615, 2003.

        ALZHEIMER'S AMYLOID ANGIOPATHY ("congophilic angiopathy") is usually present in the gray matter arteries by the time the patient is symptomatic. The fragile, amyloid-laden vessels seldom hemorrhage; the amyloid is made of Aβ (Proc. Nat. Acad. Sci. 90: 10836, 1993).

        GRANULOVACUOLAR DEGENERATION (silver-positive granules surrounded by clear zones, within neurons; the granules were identified as tau by my old teacher, William Bondareff: Am. J. Path. 139: 641, 1991) and HIRANO BODIES are often seen and are of obscure significance.

        WARNING: Many (if not most) older patients have similar changes, though to a lesser degree, without being demented, i.e., plaques and tangles in the hippocampus probably help explain a lot of the forgetfulness of some old people. We know that complaints of impaired memory tend to be proportionate to the extent of Alzheimer-like pathology at autopsy (Neurology 67: 1581, 2006). However, many forgetful older folks, even those with the "mild cognitive impairment" that is thought to precede Alzheimer's in many cases, have no senile/neuritic plaques and hence "cannot be considered to have early Alzheimer's disease" (Arch. Neuro. 63: 1771, 2006).

          * In the most recent series of brains from normal older folks, older folks who were a bit more forgetful than they should be for their age, and older folks with dementia, the "Alzheimer-like" neuropathology seems to be a continuum. This isn't really surprising. See Arch. Neuro. 63: 665, 2006.

      * It is not uncommon to find rare Lewy bodies in the forebrain in Alzheimer's, and only if they are very numerous should the diagnosis of Lewy body dementia (see below) be considered. Their presence seems to correlate with the genetics; for example, patients with mutated presenilin 1 seem to have have numerous Lewy bodies in the amygdala (Arch. Neuro. 63: 370, 2006).

    Alzheimer's disease presents a progressive, unremitting dementia. The first deficits are in mood, judgement, and recent memory. There may be motor problems. The end is always profound disability and death. Insight is lost very early; a patient who says, "I think I have Alzheimer's disease" is probably depressed instead.

      The diagnosis of Alzheimer's is still primarily clinical. Kansas Medicine 91: 132, 1990 tells you how to do the mini-mental status; <20 points is dementia.

        * A claim that these people's pupils are more sensitive to anticholinergic pupillary dilatation was the basis for a mid-1990's test-claim for the disease. It just wasn't true (Mayo Clin. Proc. 72: 495, 1997).

        The "pop" claim that getting highly educated / "exercising your brain" prevents or slows Alzheimer's seems to have been disproved by the pathologists at U. Wash (Neurology 70: 1732, 2008); probaby folks who have a lot of practice with mental games simply do better on tests of cognition despite their Alzheimer's pathology.

      UMKC's past chief of pathology, Dr. Parker, was "Mr. Alzheimer's disease" for the Kansas City area. We provided post-mortem neuropathology at no charge to families. A significant number of ante-mortem Alzheimer diagnoses are wrong: Am. J. Psych. 147: 168, 1990; our figures from outside TMC are even more discouraging.

    Most of the work in Alzheimer's is of course focused on the amyloid in the cores of senile plaques and the vessels ("amyloid beta" or "amyloid A4", or nowadays, "Aβ" or "AbetaP"), and the precursor protein of this amyloid.

      The Aβ amyloid is beta-pleated from a fragment of a much larger protein (APP, amyloid precursor protein), coded on chromosome 21 ("just like Down's syndrome"). We don't know what it's for, but it's an integral membrane protein of healthy brain; it binds to GTP-binders (Nature 362: 75, 1993), etc. Similar proteins occur all over the brain and the body (Nature 344: 497, 1990; Science 248: 1126, 1990, lots more).

      In the brain, the healthy way of processing these proteins involves breaking them down using a still-not-fully-understood protease called "alpha-secretase" or "the non-alzheimer's secretase", at positions 15-17, in the middle of the Aβ sequence, so none of the amyloidogenic peptide forms ("the good secretase pathway").

      If the precursor is broken down instead by a different enzyme, "beta-secretase" or "the Alzheimer's secretase" (now "BACE"), an amyloidogenic peptide is produced and, since the body does not metabolize amyloid well, begins to cause damage. Enzyme isolated and characterized Science 286: 735, 1999; J. Biol. Chem. 275: 21099, 2001; knockout mouse Nature Neuroscience 4: 231, 2001.

        A second protease, "gamma-secretase", is also required to produce the amyloidogenic peptide. This is the "amyloid cascade hypothesis" for the pathogenesis of Alzheimer's; how it leads to the problems with tau is unclear (see for example Am. J. Path. 171: 2012, 2007; Brain 131: 90, 2008).

          * Recently characterized, a synthetic inhibitor is now undergoing testing as a treatment for Alzheimer's (Neurology 66: 602, 2006).

          * Valsartan, an inhibitor of Abeta amyloidogenesis, seems to work in a mouse model: J. Clin. Inv. 117: 3393, 2007.

        * A newer player is neprilysin, which breaks down amyloids and is downregulated in the elderly and in late-onset Alzheimer's (Am. J. Path. 171: 241, 2007; Am. J. Path. 172: 1342, 2008).

      Immunotherapy against the Aβ42 fragment of the peptide has been shown to protect and even clear plaques from the mouse model (Proc. Nat. Acad. Sci. 98: 8850 & 8931, 2001; Nature Medicine 7: 369, 2001; Nat. Med. 6: 916, 2000). This has received tremendous attention and was the basis of the push for the "Alzheimer vaccine".

        The first human trials of the "Alzheimer's vaccine", not surprisingly, caused death from massive macrophage encephalitis (6% of those given the vaccine): Science 302: 834, 2003; Nat. Med. 9: 448, 2003; Nat. Med. 10: 117, 2004; Brain Path. 14: 11, 2004. Was this unethical? The study was stopped -- should it have been? I say no. You may disagree. Another vaccine came along: J. Immuno. 174: 1580, 2005. The vaccine did clear amyloid plaques, though not amyloid angiopathy, tau tangles or synuclein, in Alzheimer's and Lewy body disease (Am. J. Path. 169: 1048, 2006; Arch. Neuro. 64: 583, 2007).

        In July 2008, the next study was published (Lancet 372: 216, 2008). The vaccine cleared plaques, but the clinical benefit is small. In fact, some of the most-demented patients were nearly plaque-free. DARN!!

      The failure of the Alzheimer vaccine marchedy work that had been going on for several years, especially from Harvard (Nat. Med. 14: 837, 2008) -- on the evidence, AMYLOID-BETA DIMERS (Abeta dimers) directly damage structure and function at synapses themselves.

    * The new agent Pittsburgh Compound B (C11-PIB) is now being used to light up and diagnose Alzheimer's lesions on PET scan. Update Neurology 72: 1504, 2009.

    The known Alzheimer's genes

    • Amyloid precursor protein (APP, dominant; most common and usually begins in the 40's)

    • Presenilin 1 (PSEN1, dominant; subtypes with various phenotypes exist Arch. Neuro. 64: 738, 2007)

    • Presenilin 2 (PSEN2, dominant)

    • Apoprotein E (APOE; weak dominant, 2 doses worse; this increases the risk for late-onset Alzheimer's)

    • * alpha-2 macroglobulin (maybe, ? recessive)

    • * ubiquilin 1 (risk for late-onset; NEJM 352: 884, 2005)

    • * Insulin-degrading enzyme (risk for late-onset; Neurology 63: 241, 2004)

    The presenilins (PS1, PS2) somehow modify the activities of one or more of the secretases, though the big picture is still far from clear (Nat. Med. 2: 864, 1996 was the key article); perhaps the mutant forms also fail to clear amyloidogenic Aβ: Nat. Med. 3: 67, 1997; Nat Med 5; 164, 1999. Newer work shows they're calcium channels (J. Clin. Inv. 117: 1230, 2007) and the mutations that matter disrupt this activity.

      The genome-wide analysis searcing for Alzheimer's genes turns up confirms and turns up a few new loci for the late-onset forms (JAMA 303: 1832, 2010).

    * Elevated homocysteine levels as a risk factor for Alzheimer's: NEJM 346: 476, 2002. Perhaps it is a marker for something that does damage to the white matter, accentuating the Alzheimer's (Arch. Neuro. 59: 787, 2002; if the relationship is real, it's elusive Neurology 65: 1402, 2005).

    * Alpha-2 macroglobulin (the pentamer that perhaps cleaves Aβ) if partially deleted has been reported linked to sporadic Alzheimer's. Lancet 352: 293, 1998; less certain Neurology 55: 443 & 678, 2000; more Neurology 59: 756, 2002.

    Since microglia seem to be important components of senile plaques (Acta Neuropath. 77: 569, 1989, i.e., they are inflamed, perhaps because Aβ activates C1q J. Imm. 152: 5050, 1994 and microglia too of course Nature 374: 647, 1995), there is presently some empirical interest in anti-inflammatory drugs to prevent Alzheimer's, and this is supported by its low incidence in rheumatoid arthritis (aspirin) and lepers (dapsone). Despite some earlier optimism, Johns Hopkins undertook a prospective study and so far, naproxin and celecoxib haven't prevented Alzheimer's (Neurology 68: 1800, 2007; also Neurology 70: 2219, 2008). They also do not slow the established disease (Arch. Neuro. 65: 896, 2008).

    * Nobody knows why Alzheimer's patients tend to become acutely delirious as the sun sets ("sundowners"): Neurology 42: 83, 1992.

    * In 1995, I predicted the 1997 media flap about smoking preventing Alzheimer's. It doesn't.

    * A proposal for early diagnosis of Alzheimer's based in finding tau in the easily-biopsied olfactory epithelium flopped: Nature 369: 365, 1994. We may eventually diagnose Alzheimer's by finding diminished beta-amyloid 1-42 and increased tau in the spinal fluids (JAMA 289: 2094, 2003).

    * We are now observing that people who have been on statin therapy for hypercholesterolemia in midlife seem to have a much lower rate of Alzheimer's. No one knows why. See Am. J. Med. 118 (S-12A): 48, 2005.

    * Everybody wishes we had more for treating Alzheimer's. Update on the cholinergic enhancer drug donepezil: Neurology 69: 459, 2007. Obviouly this can't replace neurons once they're gone. Today's anti-Alzheimer drugs really don't work very well at all: Ann. Int. Med. 148: 379, 2008; in 2008, the FDA advised that the evidence of effectiveness was so lacking that the drugs shouldn't be used routinely (JAMA 299: 1763, 2008). Dimebon, an old Russian antihistamine, found serendipitously to help Alzheimer's (Lancet 372: 207, 2008 -- watch this one). Some "totally gone" Alzheimer's patients seem to enjoy headphones playing the music that was popular when they were teens. I respectfully request that, under these circumstances, I receive a general anesthetic and organ-harvest instead, but that is probably not going to be legal any time soon.

FRONTOTEMPORAL DEMENTIAS ("lobar atrophy", "FTLD", formerly all lumped as "Pick's disease" and now sub-sub-classified Arch. Neuropath. 114: 5, 2007) is a pattern of cortical dementia, less common than Alzheimer's. Update of the frontotemporal lobe dementias for clinicians: Med. Clin. N.A. 86: 501, 2002; pathologists Brain 128: 1996, 2005 and Arch. Path. Lab. Med. 130: 1063, 2006.

    The gross pathology is distinctive, with selective, extreme ("walnut", "knife blade") atrophy of the prefrontal cortex and anterior 2/3 of the superior temporal gyrus.

    Microscopically, we look for balloon-swollen "Pick cells", and silver-positive intra-neuronal "Pick bodies" (made from tau; they define "true Pick's"). There is widespread neuronal loss, with virtually none remaining in "walnut" areas.

    The molecular biology is just starting to become clear. Not surprisingly, the problem in "true Pick's" is with the processing of tau microtubules (Ann. Neuro. 51: 730, 2002).

    Frontotemporal dementia patients have a course similar to Alzheimer's disease. The presentation is variable. The social graces are likely to be lost earlier, as are semantic skills, while memory may be better preserved.

      * Since the orbitofrontal lobes are involved with recognizing negative emotions, these folks tend to lose the ability to recognize sarcasm (Brain 132: 592, 2009).

      Some clinicians distinguish, and correlate with areas of volume loss scans, "behavioral variant" (bvFTD -- mesial frontal lobe), "semantic dementia" (talks fine but can't remember the names of things and eventually the meanings of words, SEMD -- rostral temporal lobe), and "progressive nonfluent aphasia" (understands words but can't say them, PNFA -- left insula). There is less correlation with the presence of the pathologic lesions or their types (Neurology 72: 1653, 2009), which is no surprise, since the problem is loss of the brain cells themselves rather than the presence of inclusion bodies and so forth.

    TRUE PICK'S DISEASE is now restricted to cases with the classic tau-based Pick bodies. (I can't recommend doing a biopsy to distinguish similar, untreatable diseases.)

    "Frontotemporal dementia with ubiquitin-only" (soon to be renamed), now the most common of the frontotemporal dementias (Arch. Neuro. 65: 1481, 2008; Brain 130: 1148, 2007). FTLD-U photos Am. J. Path. 169: 1343, 2006. It is now clear that the "ubiquitin-only" bodies are composed largely of TDP-43 (Science 314: 130, 2006; Am. J. Path. 173: 182, 2008). This links it to common and most familial amyotrophic lateral sclerosis, and there's now talk of these being a comtinuum ("multisystem TDP-43 proteinopathies" -- Arch. Neuro. 66: 180, 2009) and of the FTLD-U, TDP-43 positive patients having subtypes with different pathologies correlating with different clinical syndromes (Arch. Neuro. 64: 1449, 2007).

    * PRIMARY PROGRESSIVE APHASIA is still described as a Pick variant (last big review Neurology 44: 2065, 1994) sometimes with more atrophy on the left and with speech going long before anything else. There are balloon cells, but no Pick bodies; there are often ubiquitin-positive inclusion bodies that remain to be characterized. Just as in FTLD-U, a few percent of patients have progranulin mutations (Arch. Neuro. 64: 43, 2007; Brain 131: 732, 2008). Exacty where this disease fits is up for grabs right now (Neurology 72: 1562 & 1653, 2009). Probably most cases were what we now call the progressive nonfluent aphasia variant, but some Alzheimer's patients present with language problems before anything else and this may become the name of a syndrome, the precise diagnosis waiting for autopsy.

      We can now distinguish Alzheimer's presenting as similar speech problems from "primary progressive aphasia" by scan (Neurology 70: 25, 2008).

    Yet another variant features a combination of frontotemporal lobe dementia and motor neuron disease, complete with Bunina bodies (Arch. Neuro. 63: 506, 2006).

    Most frontotemporal dementias are sporadic. A tau/MAPT mutation causes familial Pick's with tau inclusions as you'd expect: Brain 127: 1415, 2004. Mutations of the gene GRN ("progranulin") produces FTLD-U (mutations and pathology Brain 129: 3081 & 3091, 2006) -- evidently detectable by a blood assay (Brain 132: 583, 2009). A genetic syndrome (VCP / p97) causes frontotemporal dementia, Paget's of the bone, and inclusion body myositis (Brain 130: 381, 2007). We'll see the genetics of FTDP-17 (Pick's-and-Parkinson's) below.

Pick's disease

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Pick's disease

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HUNTINGTON'S DISEASE ("Woody Guthrie's disease")

    This is an autosomal dominant disease (gene Htt, protein huntingtin, * chromosome 4, gene cloned Cell 72: 971, 1993, Nature 362: 408, 1993) with complete penetrance. Neurons disappear, most spectacularly in the head of the caudate nucleus.

      * The reason for the localization of the damage to the corpus striatum seems to be the mutant huntingtin's interaction with a protein called Rhes that is selectively localized there (Science 324: 1327, 2009).

    Between age 20 and age 50, mental function diminishes (* "subcortical dementia"), behavior, insight, and mood change for the worse (one group coins the phrase "beyond disgust" for the inability to recognize negative emotions and the things that should provoke them: Brain 130: 1715, 2007). Then a movement disorder (chorea and athetosis, resembling a jerky dance) develops. Profound disability and death occur after 10-20 years.

Woody Guthrie
Woody
Guthrie

    The gene (for "huntingtin") is a "Sherman's paradox" gene, confirming the clinicians' impression that Huntington's appears earlier from generation to generation. The mutation involves expansion of CAG sequences. The proteins that are produced have poly-glutamine sequences, which un-solubilize the protein, causing it to accumulate and gum up the nucleus (Cell 90: 537, 1997; Nat. Genet. 18: 150, 1998). All about Huntington's genes around the world: NEJM 330: 1401, 1994.

    At autopsy, there is moderate atrophy of the whole brain, and striking atrophy of the head of the caudate nucleus (* to a lesser extent, the putamen and globus pallidus); there is generally considerable atrophy of the frontal cortex and locus ceruleus as well.

    Of course, it's possible to predict who will get the disease. This is sensitive ethically and emotionally.

      Early accounts of patient screening and responses showed common sense (Br. Med. J. 304: 1593, 1992 is still good).

      * Venezuela has a tremendous amount of Huntington's, centered on a single region; see Lancet 364: 569, 2004. All victims are descended from a single man. If someone has a parent with the disease, he/she tries to have as many children as possible in order for there to be a caregiver if he/she becomes disabled. Since genetic testing and prenatal screening are not options for Venezuelans because of the politics, the situation can only get worse.

      * Some countries (and not just the Third Reich) have tried to control Huntington's by government policies. Review of this: Am. J. Hum. Genet. 50: 460, 1992. Recently, a pair of Swiss ethicists were horrified after 73% of law students and 39% of medical students thought possible carriers should be strongly encouraged to get tested and especially not to have babies that are going to get Huntington's (Clin. Genet. 64: 327, 2003). The authors believe that "eugenics" (i.e., even encouraging people to make their reproductive decisions with a thought to the good of society) is fundamentally and profoundly immoral and that this is not open to debate. I don't agree -- and the law students, who focus on how people's actions affect those around them -- evidently did too. A discussion (JAMA 290: 1219, 2003) of the "ethical dilemmas" posed by Huntington's testing ("No! No! Don't tell my children they and the children they're going to have may be at risk too!") showcased (at least for me) a lack of common sense and regard for the lives of others. ("Paternalism! Bad!") More recent discussions of the release of confidential genetic information have focused instead on the family's autonomy ("Autonomy! Good!"). Stay tuned.

    * Striatal embryonic allografts have been tried in humans for Huntington's Nat. Med. 4: 727, 1998. Autopsy studies on these patients show that the cells survived but didn't integrate well into the corpus striatum, explaining the lack of clnical improvement (Neurology 68: 2093, 2007).

    An inhibitor of the transglutiminase that cross-links huntingtin is the first medication to slow down Huntington's disease, at least in mice (Nat. Med. 8: 143, 2002). Trehalose and/or Congo red (!): Nat. Med. 10: 123, 2004.

    * Fun to know: Huntington described the disease as a med student; he was from a long line of doctors on Long Island who'd observed the disease in a long line of neighbors over several lifetimes.

{32870} Huntington's brain, gross; not much caudate

Huntington's disease

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Huntington's disease

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Huntington's
Pittsburgh Pathology Cases

    * Huntington mimics include an allele at the prion locus (HDL1, "Huntington's disease-like 1"; Brain 126: 1599, 2003) and one at the junctophilin 3 (JPH3) locus (Neurology 61: 1002, 2003; update J. Neuropath. 67: 366, 2008). Neuroferritinopathy, caused by a mutation in the ferritin light chain, causes accumulation of ferritin especially in the basal ganglia (Brain 130: 110, 2007). There are others.

PARKINSON'S DISEASE ("paralysis agitans") and its relatives: Parkinsonism review: NEJM 339: 1130, 1998; Lancet 363: 1783, 2004; J. Clin. Inv. 116: 1744, 2006; Lancet 373: 2055, 2009; Nat. Med. 16: 653, 2010

Parkinson's

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Parkinson's

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Parkinson's disease
Lewy bodies
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Alpha synuclein staining
UK Tissue Bank
Good illustrations

    This is a family of disorders involving destruction of the dopaminergic neurons of the substantia nigra (i.e., the fibers that talk to the striatum) and locus ceruleus (* and the dorsal motor nucleus of X: Neurology 42: 2106, 1992; the raphe, and some others).

    Grossly, you'll see "depigmentation of the substantia nigra", no matter what the cause.

{17754} Parkinson's vs. normal (midbrain sections)

    The result of the neuronal loss is a movement disorder, with "pill-rolling" resting tremor, festinating gait, bradykinesia, cogwheel rigidity, and mask-like face. Many patients become demented (the pathology correlate seems to be beta-amyloid in the striatum J. Neuropath 67: 155, 2008; no correlation with co-existing Alzheimer's). Please remember how to distinguish dementia from depression that is so often seen in Parkinsonism.

    Known causes include Von Economo's encephalitis ("post-encephalitic parkinsonism", with neurofibrillary tangles in the substantia nigra neurons instead of Lewy bodies), some cases of chronic traumatic encephalopathy (professional boxers South. Med. J. 82: 543, 1989), and the "designer drug" (MPTP, "Ecstasy") fiasco of a few years ago. Dopaminergic neurons are the only ones that take the drug up, and it produces mitochondrial damage and a permanent Parkinson-like syndrome ("The case of the frozen addicts!")

    Most cases of Parkinsonism do not seem to be familial. The known Parkinsonism genes:

    • alpha-synuclein, a presynaptic protein involved in synaptic plasticity; in the disease, it twists and accumulates (autosomal dominant PARK1=SNCA; Neurology 43: 69, 1993; Geriatrics 46(S1): 52, 1991; Neurology 45: 502, 1995; Science 256: 2045, 1997 Nat. Genet. 18: 168, 1998; Nat. Med. 8: 564 & 600, 2002); one extra copy gives parkinsonism without dementia, while two extra copies give parkinsonism plus Lewy body dementia: Lancet 364: 1167, 2004.
    • tyrosine hydroxylase (autosomal recessive; Neurology 41: 719, 1991).

    • Parkin, autosomal recessive (PARK2) early-onset Parkinsonism without Lewy bodies: Nature 392: 544, 1998; NEJM 342: 1560, 2000; Arch. Neuro. 64: 421, 2007; it's the protein that ubiquitinates synphilin-1 which in turn interacts with synuclein (Nat. Med. 7: 1108, 2001; update Science 304: 1328, 2004).
    • Usually no Lewy bodies

    • PARK3 and PARK4 do have Lewy bodies; stay tuned
    • tau/MAPT (a variant, Picks-plus-Parkinsonism, no Lewy bodies: Neurology 54: 1787, 2000; Am. J. Path. 153: 1359, 1999; Brain 128: 2645, 2005)
    • LRRK2 / PARK8 / dardarin (Brain 128: 2786, 2005. Lewy bodies
    • glucocerebrosidase ("GBA", some Ashkenazi alleles; NEJM 351: 1972, 2004); Lewy bodies

    In non-familial Parkinsonism having an identical twin with the disease does NOT increase your risk. This is now a robust finding (Neurology 63: 305, 2004). Since environmental risk factors are also elusive, and since twins tend to spend much of their lives together, your lecturer believes that there is a post-zygotic mutation involved -- and since the disease tends to announce itself asymmetrically, perhaps there is also a mitochondrial component.

    * The epidemiologic link between insecticide and/or herbicide exposure and Parkinsonism continues to be discussed, especially since MPTP produces permanent Parkinsonism and works like many insecticides on the mitochondrial complex 1 system. Nobody's been looking hard at the epidemiology in recent years; living your life in farmland seems to be a risk, and there was a study where Dieldrin was found in 6 of 20 Parkinson's brains, and none of 14 controls (Ann. Neuro. 36: 100, 1994), and two pretty-good-looking epidemiologic studies (Neurology 43: 1150, 1993; Neurology 42: 1328, 1992). Rotenone, which like other insecticides resembles MPTP chemically and pharmacologically, produces Lewy body parkinsonism in mice (Science 290: 1068, 2000). An animal model showing enhancement of synucleinopathy by insecticides: Am. J. Path. 170: 658, 2007. So far there's no model of the chronic disease using herbicides, though some of these produce acute effects on the dopaminergic system as do many other substances (Science 290: 1068, 2000).

    The claim that cigaret smoking is protective against Parkinsonism is by now clearly true (Neurology 45: 1041, 1995; Epidemiology 10: 327, 1999). So is caffeine (Drugs & Aging 18: 797, 2001).

      * Nobody knows why, but easiest to believe is that tobacco smoke contains monoamine oxidase inhibitors. Smokers reportedly have only about 40% as much MAO in their brains as do non-smokers, the enzyme generates hydrogen peroxide at the synapses, and this may be what triggers destruction of dopaminergic neurons (JAMA 297: 1419, 2007). This fits with the observation that the nicotine patch works better when combined with the antidepressant bupropion (Zyban).

    Most Parkinson's cases are "idiopathic", and begin in later middle age. Look for the distinctive (but not pathognomonic) "Lewy bodies" in dopaminergic (and other) neurons. Big autopsy series: Arch. Neuro. 50: 140, 1993.

    * Acupuncture and every other "complementary / alternative remedy" studied for Parkinsonism have been flops (Neurology 57: 790, 2001).

    * Around 7% of Parkinson patients taking dopaminergic medications become pathological gamblers (BJM 334: 810, 2007).

    The adrenal medulla autotransplantation experiment resulted in non-viable grafts. An animal model of Parkinson's responds dramatically to embryonic stem cell therapy: Proc. Nat. Acad. Sci. 99: 2344, 2002. Update Neurology 66(S4): S89, 2006. Even better Proc. Nat. Acad. Sci. 105: 5856, 2008). The proposal to try stem cells in people has turned into a symbolic political battle which I think most people who have devoted their lives to the battle against disease find disheartening. We await more publications, but it's a hopeful area (Nat. Med. 7: 381, 2001).

    Remember the parkinsonism mimics, which include multi-infarct disease, manganese toxicity, Lyme disease (Arch. Path. Lab. Med. 127: 1204, 2003), and now West Nile.

    * James Parkinson, the first person to distinguish and describe the illness, was a progressive political activist throughout his life. As a young man, he was implicated in the "pop-gun" plot to assassinate George III with a poisoned dart; thankfully, the business was soon forgotten. Later in life, he was a strong advocate for the protection of the mentally ill and their families, and became interested in the new sciences of paleontology and geology.

CORTICOBASAL DEGENERATION (formerly "Pick's Type B") is a dementing disease with balloon cells, a distinctive tau-based pathologic lesion around astrocytes, and motor problems (notably alien limb, "My hand escaped and is doing its own thing.")

    This tends to be rollow a rapid course (Brain 130: 1148, 2007).

    Tau-positive inclusions around the astrocytes are the histological hallmark of corticobasal degeneration. They're called "astroglial plaques" and the tau looks like puffs of smoke surrounding the astrocyte body.

    * These people often have neurofibrillary tangles, with straight rather than twisted filaments, as in progressive supranuclear palsy. Also look for tau staining immediately around the nucleus.

    A few genes are known or suspected, most notably a progranulin allele (Brain 131: 732, 2008).

    The disease is notoriously unresponsive to therapy. Reviews: J. Neuro. Neurosurg. Psych. 68: 304, 2000; Arch. Neuro. 55: 957, 1998, pathology J. Neuro. 246 S-2: II 6-15, 1999.

MULTIPLE SYSTEMS ATROPHY is now considered a single disease, because of its distinctive inclusions in the oligodendoglia.

    The inclusions (* Papp-Lantos bodies) contain alpha-synuclein. Nobody really understands them.

    STRIATONIGRAL DEGENERATION (* multiple system atrophy P for "Parkinson-like") is a degenerative disease in which the caudate and putamen atrophy along with the substantia nigra. Patients have a similar clinical syndrome to Parkinson's, but do not respond to L-Dopa therapy and do not have Lewy bodies.

    SHY-DRAGER (* multiple system atrophy A for "autonomic"; see Ann. Int. Med. 125: 194, 1996) is striatonigral degeneration with the loss, in addition, of the intermediolateral neurons of the spinal cord and resulting autonomic disturbances. I've never seen a case, though it's in the differential diagnosis of every patient with orthostatic hypotension, and is perennially discussed.

    OLIVOPONTOCEREBELLAR DEGENERATION (* multiple system atrophy C for "cerebellum") is still the name for a grab-bag of diseases with similar anatomic pathology -- loss of neurons from the basis pontis, cerebellar cortex, substantia nigra, and inferior olive. (The inferior olive is reported to disappear whenever the cerebellum is wiped out, due to post-synaptic degeneration.) It still includes the genetic spinocerebellar ataxias I and II. In non-hereditary olivopontocerebellar degeneration, one often sees the oligodendroglial inclusions typical of mutliple systems atrophy.

PROGRESSIVE SUPRANUCLEAR PALSY ("PSP", Steele-Richardson) is an underdiagnosed, fairly-common (Neurology 44: 1015, 1994; Med. Clin. NA 83: 369, 1999; J. Clin. Path. 54: 427, 2001) dementing disorder of older adults with eye movement disorders (especially, problems with downward gaze), other movement disorders, and often dementia.

    Neuronal loss is most prominent in the deeper brain structures, and the key to diagnosis is "globose" neurofibrillary tangles found mostly in the oculomotor equipment, basal ganglia, substantia nigra, subthalamic nuclei and various brainstem structures. Abnormal astrocyte-fiber tufts are also quite characteristic distinctive histologic sign: Acta. Neuropath. 96: 401, 1998. NIH workshop, with criteria for diagnosis: Neurology 44: 2015, 1993 (* they want us to call it Steele-Richardson-Olszewski syndrome, nobody's going to...), also Brain 118(3): 759, 1995. * Neurofibrillary tangles in PSP have straight, rather than twisted, filaments. PSP as a taupathy; Lancet 356: 170, 2000.

    A parkinsonism/PSP variant that is rampant on the island of Guadeloupe, complete with the NFT's in the substantia nigra and subthalamic nuclei, and astrocyte tufts (Brain 125: 801, 2002) is probably caused by ingestion of the jungle-fruit Annona muricata neurotoxin annonacin (Brain 130: 816, 2007; J. Neurosci. 27: 7827, 2007). "Complementary medicine" folks take note: This is one of the supposedly-good-for-you alkaloids in the herbal cancer remedy "Graviola."

    * A mutant tau allele is a feature of at least one kindred with the ultra-rare dementing disorder "progressive subcortical gliosis" (Nat. Med. 5: 454, 1999); another lacks it (Neurology 72: 260, 2009).

THE OTHER TAUPATHIES

    FTDP-17 ("frontotemporal dementia with parkinsonism linked to chromosome 17") is caused a mutation of tau itself (Mech. Aging 127: 180, 2006; Brain 128: 2645, 2005) or the nearby protein progranulin (Nature 442: 916, 2006; Arch. Nero. 65: 460, 2008). As with other subcortical taupathies, you might see tau inclusions in the oligodendroglia (J. Neurosci. 25: 9493, 2005).

ARGYROPHILIC GRAIN DISEASE, with silver-staining tau granules in limbic neurons (different from granulovacuolar degeneration, and without other Alzheimer features) is a common, newly-recognized entity seen in older folks, with amnesia, delusions of persecution, and agitation (Acta Neuropath. 111: 320, 2006; now well-known Brain 131: 1416, 2008.) It's been under-recognized since special variants of the silver stains are required to see its lesions.

    Pathologists recognize:

    • silver-staining 8-micron grains in the dendrites
    • hyperphosphorylated tau as coiled bodies in oligodendroglia, and in the astrocytes of the limbic system
    • balloon cells in the amygdala
    • neurons staining for hyperphosphorylated tau, the tangle precursor, especially in the entorhorhinal cortex (as in early Alzheimer's)

LEWY BODY DEMENTIA features neurons packed with Lewy bodies throughout much of the brain. These patients have a rapid Alzheimer-like illness with some extrapyramidal symptoms (stiff and slow but usually no tremor), visual hallucinations, and (often) exquisite sensitivity to the older neuroleptic drugs (chlorpromazine, etc. -- try one of the newer "atypical antipsychotics" instead.) It's not rare, but seldom diagnosed in life. See Br. Med. J. 305: 673, 1992; Neurology 42: 2131, 1992; clinico-pathologic correlation including tips on how to tell this from Alzheimer's in life Arch. Neuro. 59: 43, 2002.

    * Most of these patients also have tangles; the more tangles, the harder it is to tell it from Alzheimer's clinically (Neurology 60: 1586, 2003). * Update on selective involvement of neurons in the caudate, and a correlation with neurophysiology: Neurology 66: 1591, 2006.

    * Glucocerebrosidase mutations and Lewy body dementia: Arch. Neuro. 66: 578, 2009.

TORSION DYSTONIA ("dystonia musculorum deformans") is a disease of children in which the muscle tone increases around the body, twisting it into curious positions. The one known gene is Torsin A (TOR1a / DYT1) which does not always express completely (Neurology 59: 445, 2002; Arch. Neuro. 57: 333, 2000.) The anatomic pathology in the brainstem includes inclusion bodies (not well-characterized; Ann. Neuro. 56: 540, 2004) and since the disease comes on over time, there's probably neurodegeneration involved. Neurosurgical procedures on the deep brain structures has resulted in spectacular recoveries (review Ped. Neuro. 14: 145, 1996).

* HEREDITARY SPASTIC PARAPLEGIA ("familial spastici paraparesis, etc.; Arch. Neuro. 60: 1045, 2003) is a family of thankfully-rare progressive genetic disorders (dominant and recessive) of varying expressivity. For some reason, the long axons in the corticospinal tracts that supply the legs undergo degeneration with the neurons themselves being preserved. At least eight loci are already known (J. Neuro. Neurosurg. Psych. 72: 43, 2002; pathology of the "spastin" mutant variant Neurology 55: 89, 2000).

ESSENTIAL TREMOR ("benign familial tremor") is a very common (1-2% of humankind), usually banal (sometimes severe) intention tremor. It is inherited as an autosomal dominant (possible loci Neurology 68: 790, 2007 and Brain 130: 1456, 2007), first manifests around age 20, and typically vanishes as soon as the "patient" drinks one beer (i.e., here's the three questions you need to ask to pretty-much clinch the diagnosis). If the patient really wants to be treated, or it's severe, try low-dose propranolol or gabapentin (Arch. Neuro. 56: 807, 1999). More important, explain the nature of the process, and that it is NOT Parkinsonism or mental illness.

    A group at Columbia NYC finally looked at brain-bank specimens from people with essential tremor and found a couple of different patterns (Brain 130: 3297, 2007).

THE SPINOCEREBELLAR ATAXIAS (update Mayo Clin. Proc. 75: 475, 2000)

    This array of autosomal degenerative diseases has recently been sorted out thanks to the Human Genome Project. Except Friedreich's and ataxia with vitamin E deficiency, all are autosomal dominant. The pathologist sees only neuronal loss and maybe gliosis.

    TYPE I SPINOCEREBELLAR ATROPHY feature damage to the gene for "ataxin 1", and this also exhibits long tandem repeats and Sherman's paradox (see below; Nat. Neurosci. 3: 157, 2000). So do TYPE II (ataxin 2; Eur. J. Hum. Genet. 7: 841, 1999) and TYPE III (Joseph's, a Portuguese ethnic disease and probably the commonest in this group, ataxin 3). All these do their harm by producing a product whose long repeats gum up the nucleus. (I predicted in 1990 these would prove to be Sherman paradox diseases.) As in the "olivopontocerellar atrophy" variant of multiple systems atrophy, neurons are selectively lost form the basis pontis, inferior olives, cerebellar cortex, and substantia nigra.

    FRIEDREICH'S ATAXIA is an autosomal recessive disease with somewhat variable expressivity. Onset is in late childhood, when pes cavus (high-arched feet), clumsiness and speech problems develop. Patients become wheelchair-bound after a few years, and may have a cardiomyopathy with thick walls (not the "classic" hypertrophic cardiomyopathy though). There is gliosis of the posterior columns, dorsal corticospinal tract, and spinocerebellar tracts; the cerebellar cortex and other motor areas may also be involved. The cause is trinucleotide repeats in frataxin, a gene responsible for keeping iron from accumulating in mitochondria; Gene and review: Science 271: 1423, 1996; update Arch. Neuro. 59: 743, 2002.

      Unlike other long-repeat diseases, this is a loss-of-function gene, hence the recessive inheritance. Because of Sherman's paradox, Friedreich's used to be considered "often dominant". Any idea how this could have been? A clinician gives the same answer as you did: Arch. Dis. Child. 83: 74, 2000.

      Update for clinicians: Arch. Neuro. 64: 558, 2007. The antioxidant idebenone (molecularly similar to CoQ) is the most promising treatment, and seems to slow the disease (how?): big study Neurology 60: 1676 & 1679, 2003.

    ATAXIA WITH VITAMIN E DEFICIENCY mimics Friedreich's, but is caused by lack of vitamin-E transfer protein. Of course this is also autosomal recessive. Giving the vitamin in big doses is effective treatment. See NEJM 333: 1313, 1995. Though very rare, it's the only really treatable entity in this group, so be sure to think of it!

    * Smith's dentatorubral atrophy is yet another Sherman's-paradox disease ("atrophin"; J. Biol. Chem. 274: 8730, 1999).

    * The EPISODIC ATAXIA family includes a mutation in the voltage-gated potassium channel gene; ataxic / dysarthric episodes especially follow a startle.

    We've already mentioned ATAXIA-TELANGIECTASIA (gene ATM). The mechanism by which it causes neurodegeneration has remained elusive.

    * Men carrying mild alleles of fragile X (i.e., not enough tandem repeats yet) are prone to develop cerebellar ataxias and dementia (Brain 125: 1760, 2002.)

AMYOTROPHIC LATERAL SCLEROSIS ("Lou Gehrig's disease"; "creeping paralysis"; motor neuron disease complex; Am. Fam. Phys. 59: 1489, 1999; NEJM 344: 1688, 2001; BMJ 336: 658, 2008)

    "Motor neuron disease complex" is actually four diseases, featuring loss of the motor neurons

      1. Amyotrophic lateral sclerosis (loss of upper and lower motor neurons); this is the common one

      2. Progressive bulbar palsy (cranial nerves are most severely affected)

      3. Progressive muscular atrophy (lower motor neurons only)

      4. Primary lateral sclerosis (upper motor neurons only)

Lou Gehrig
Lou Gehrig

    ALS is a disease of older middle age, progressing to profound disability (usually without mental impairment) in a few years. Most ALS cases are sporadic (but see below). There is a slight male predominance

      Current thinking has involved destruction of motor neurons by excitotoxicity (Mayo Clin. Proc. 66: 54, 1991; J. Neurol. 247-S1: I-7, 2000). This is supported by the finding that the anti-glutamate agent riluzole causes a modest slowing of the progression of ALS (NEJM 330: 585, 1994); it's now the only medication approved in the US for ALS and prolongs life by about two months (JAMA 298: 207, 2007; Clin. Pharm. Ther. 83: 718, 2008).

      The sick neurons contain ubiquitin-positive inclusions of various sorts, thought to be altered or abnormal proteins that resist degradation (update Acta Neuropath. 113: 535, 2007). Most distinctive is the Bunina body of non-superoxide-dismutase-related disease, which looks like a string of beads, composed largely of cystatin C found in the remaining lower motor neurons.

      There are other inclusions as well in most types of ALS; these are cystatin C-negative but stain with ubiquitin and TDP-43 (Science 314: 130, 2006; Am. J. Path. 173: 182, 2008); some of these patients have Bunina bodies, some don't (Arch. Neuro. 66: 121, 2009).

      The link between cycad (false sago palm) flour and ALS-dementia-parkinsonism complex of the indigenous Chamorro people of Guam remains speculative. There is now an animal model using the toxin cycasin (Exp. Neurol. 155: 11, 1999). Thankfully the disease is becoming less common, but has not vanished. The locals have always washed the flour, supposedly being aware of the toxin; one group links the disease to the consumption of the ethnic delicacy of the fruit bat that lives on the sago palm (Neurology 58: 956, 2002). Like other ALS syndromes, this one is now known to be TDP-43 positive (Brain 130: 1386, 2007).

      About 10% of ALS is hereditary.

        The classic gene is a defective superoxide dismutase gene: Science 261: 986 & 1087, 1993; Nature 362: 59, 1993; transgenic mice with the mutant form get sick too Proc. Nat. Acad. Sci. 93: 3155, 1996. The mechanism remains totally obscure; in one model, the protein is misfolded: Brain 127: 73, 2004.

        As you'd expect, mutated TDP-43/TARDBP has been discovered as a cause of familial ALS (Arch. Neuro. 65: 1185, 2008).

        * Motor neuron disease from mutant dynactin: Nat. Genet. 33: 455, 2003.

        * Another locus (alsin, ALS2): Nat. Genet. 298: 160, 2001; Arch. Neuro. 60: 1768, 2003.

      Amyotrophic lateral sclerosis is the classic disease cited in considerations of physician-assisted suicide. (Why?) About one Dutch patient in five now chooses this route (NEJM 346: 1638, 2002). And a majority will consider assisted suicide, but most will choose hospice instead (NEJM 339: 967, 1998).

      The key illness to rule out in apparent ALS is MULTIFOCAL MOTOR NEUROPATHY, caused by autoantibodies against GM1 ganglioside. This responds to treatment as other autoantibody diseases (cyclophosphamide, gamma globulin, now rituximab Neurology 63: 2178, 2004).

      * KENNEDY'S DISEASE is a bulbospinal atrophy and lack of masculinization of male patients, caused by lack of an androgen receptor. This is yet another trinucleotide repeat disease.

Amyotrphic lateral sclerosis

WebPath Photo

Amyotrophic lateral sclerosis

WebPath Photo

Amyotrphic lateral sclerosis

WebPath Photo

    WERDNIG-HOFFMAN DISEASE (spinal muscular atrophy type I) is an autosomal recessive disease causing loss, in the few months before and after birth, of most of the lower motor neurons. It is the most severe of the spinal muscular atrophies, caused by various mutations at the SMN ("survival motor neuron") locus (Nat. Genet. 16: 265, 1997); we covered these under "Muscle".

MENTAL ILLNESS

    SCHIZOPHRENIA (Lancet 353: 1425, 1999; Mayo Clin. Proc. 77: 1068, 2002) is the most important of the "functional psychoses", supposedly affecting about 1% of humankind in every culture, every bit as devastating as Alzheimer's disease, but under-investigated (i.e., patients don't lobby, there's an awful stigma, and the rich are seldom affected). Schizophrenics consume 2.5% of health care expenditures, constitute 10% of the totally and permanently disabled, and represent around 14% of the homeless (Psych. Clin. N.A. 16: 413, 1993). Schizophrenia reviews: Lancet 346: 477, 1995; NEJM 330: 681, 1994. Schizophrenia as a cause of death (meds, agitated delirium, or the disease itself): J. For. Sci. Int. 48: 164, 2003.

      * There are rumors that schizophrenia is becoming less common among young people in the U.S. Perhaps this is because of 'flu shots, and/or perhaps this is due to fetal monitoring and more frequent cesarean sections (and perhaps this will prove to be the great benefit of fetal monitoring; stay tuned here.)

Mad Meg

Brugel's "Mad Meg"

Even in the DSM-IV era, I find Bleuler's "Four A's" helpful: Autism (apparent absorption in self and fantasy), Ambivalence (maintaining contradictory attitudes in logic-tight compartments, with striking lack of insight), loose Associations, and flat Affect. In schizophrenia, these are much more striking even than in us "normal folk".

    Don't confuse schizophrenia ("fragmentation of the mind") with "multiple personality", a dissociative state that rarely occurs spontaneously but that is easy to produce iatrogenically using hypnosis. (The fad is over -- induce multiple personalities today, or even talk to one, and you'll end up in court.) Update on multiple personality and false memory syndrome as discredited ideas induced by pseudo-therapists: Lancet 375: 1243, 2010.

Sensitive physicians know that the negativism, coldness, and lack of motivation of the schizophrenic can be as upsetting to family members as the delusions and hallucinations. Tell them it's nobody's fault and that it isn't that they are not loved.

Reasonably good models for schizophrenia (i.e., both being very crazy and being oriented in the three spheres) include acute intermittent porphyria, lupus, chronic mercury poisoning, ergotism, pellagra, neurosyphilis, frontal lobe meningioma, and some of the psychedelic experiences.

One Flew Over the Cuckoo's Nest
One Flew Over the
Cuckoo's Nest

Shakespeare's Ophelia

Until recently, all public discussion of schizophrenia was dominated by ideology. In the 1960's ("B.F. Skinner says..."; "All people are born the same and if you aren't getting what you want, it is society's fault"; etc.), behaviorists wrote dogmatically about "the schizophrenogenic mother" ("She said to the child, 'I love you', but her body language said otherwise, and this prevented the child from distinguishing fantasy from reality"; "the double bind", etc., etc.) In the early 1970's, it was all the fault of "the schizophrenogenic father" instead; as with the "S-mother", evidence was "anecdotal" (i.e., the biological parents of crazy people act screwy themselves; stress sometimes precipitates symptoms) and "based on sound theory" (i.e., "all people are born the same", the left-wing/Skinnerian ideology of the day). Some 'sixties revolutionaries discussed schizophrenia as "a disease caused, more than any other, by our reactionary society", or denied its existence altogether (a Dr. Thomas Szasz, author of The Myth of Mental Illness, described witch-hunts and incarcerating people just for being different). 'Sixties rhetoric emphasized that traditional society was unreasonable and thus the people in the mental hospitals must be the sane ones. "The King of Hearts" put this on the silver screen. Ken Kesey (One Flew Over the Cuckoo's Nest) and Dr. R.D. Laing (The Politics of Experience) wrote their best-sellers. (Dr. Laing's own life-story was not nice.) The ACLU defended the rights of crazy people to refuse treatment (one 1970's study showed 99% were totally grateful after being brought back to earth). And some psychologists inveighed against the use of the obviously-effective phenothiazine drugs, which began cutting through hallucinations and delusions as soon as they were introduced in the 1950's. Confusing fantasy with reality always causes problems, and the beautiful 'sixties rhetoric resulted in disaster for the mentally-ill and their families. Today, only a few psychoanalysts still talk about curing schizophrenia through psychotherapy, and the rest of the world (even the other psychiatrists) just laughs at them (Nature 354: 693, 1991 was the last gasp). There are still occasional complaints from non-physicians about psychiatry being wicked because it is "authoritarian", or obsolete because it is "culture-bound" or "institutionalized" or "modernist rather than postmodernist" (Br. Med. J. 322: 724, 2001). These people ignore the fact that for the past fifty years, free-world psychiatrists have only used coercion when a person cannot take care of himself/herself or a danger to others, and an examination of any psychiatry textbook will show that the discipline is characterized by a variety of perspectives and ways of understanding a particular person's problems.

The end result of all of the "enlightened thinking", of course, was de-institutionalization ("out of the back wards, into the back alleys"). This pleased the Left ("We're for every individual's freedom to be different"; "Even though the inmates got free food, clothing, shelter, medical care, and protection, and were otherwise unemployable, it violated their civil rights to have them work in the laundry and not get minimum wage and benefits"), the Right ("We're against able-bodied people living at public expense"), optimistic physicians ("The grateful patients will come regularly to their community mental health centers to get their medicines refilled"), and real humanitarians (there were, after all, serious abuses in the old "asylum" system). Well, everybody was pleased at first.... Today, the non-compliant mentally-ill whose families can no longer stand them are homeless, and this gets described as a "human rights problem" by the same people who got the asylums closed in the 1970's. Do you think Dr. Szasz ("Mental illness is a myth") has ever talked to his local "bag person"? By the way, schizophrenics ARE more likely to commit crimes, including violent crimes, including murder (Psych. Clin. N.A. 15: 575, 1994; a schizophrenic is 8 times as likely to commit murder as a non-psychotic counterpart: Arch. Gen. Psych. 53: 497, 1996), and only a fool believes that psychiatry can protect the public in today's political-economic "mental-health" environment. I hope that no one was surprised by an enormous study from Duke (Arch. Gen. Psych. 63: 490, 2006) that withdrawn schizophrenics rarely commit crimes but that people raging around and having delusions of persecution are very likely to hurt somebody. The best we're doing nowadays is "leveraging" -- the person doesn't get his/her welfare check if he/she does something violent (Am. J. Psych. 163: 1404, 2006; and the lawyers are all over this; it's emerged that during a six-month period, about 20% of those collecting welfare for mental illness will admit to hurting someone or at least threatening someone with a lethal weapon; same rate as the Duke study above.) The truth is that schizophrenics are more likely than non-schizophrenics to commit all categories of crime except sex crimes (Lancet 355: 614, 2000). In fact, people who stalk strangers (rather than previous sex partners) are usually psychotic (Lancet 355: 199, 2000). Even writers who seem to be advocates for "community mental health" and who emphasize that a majority of stranger-murders result from fights in bars or among druggies cannot hide the reality of senseless violence from schizophrenics (especially against family members and friends: Br. Med. J. 328: 754, 2004). As part of the illness, many schizophrenics do not believe they are sick, and do not want to take their medicine. Thanks mostly to "laws that protect the rights of the specially-challenged", it remains extremely difficult to keep a schizophrenic confined even after multiple episodes of dangerous behavior. The shooting of two guards in the US capitol by a chronically belligerent, chronically threatening, non-compliant schizophrenic named Russell Eugene Weston who had just been given "Greyhound therapy" (a one-way bus ticket out of the state) by the Montana mental-health system should have had an impact, but it didn't. Michael B. Laudor, a schizophrenic who successfully completed the curriculum at Yale Law School and who sold book and movie rights to his success story for $2 million, stopped taking his medicine and a few days later stabbed his pregnant girlfriend to death. In both of these high-profile cases, the families knew there was going to be trouble, but couldn't do anything. A mental patient is most likely to kill a family member when the family denies, misunderstands, or "spiritualizes" the illness (chilling reading: Crim. Behav. Mental Health 15: 154, 2005). The much-hyped recent "study" (Arch. Gen. Psych. 55: 393, 1998) finding that mentally-ill people in the community were no more likely to be violent than their underclass neighbors suffered from serious flaws, including omitting anybody who had been in jail, and not counting threats of violence, swinging-and-missing, fire-setting, or trashing rooms as being violent. More recently, several studies have made it clear that schizophrenics are much more likely to commit violent crimes, especially violent sex crimes (Crim. Behav. Ment. Health 14: 108, 2004 -- note the conflict with some previous studies). A schizophrenic (compared with a non-schizophrenic) is over four times more likely to have been convicted of a crime (21.6% vs. 7.8%), and a violent crime (8.2% vs. 1.8%); the rate of substance abuse among schizophrenics is tremendously high but this doesn't explain all of this (Am. J. Psych. 161: 716, 2004; also JAMA 301: 2016, 2009). At present, there are maybe 300,000 or 400,000 chronically mentally ill Americans confined in jails and prisons. (Many are in jails for vagrancy.) There are only about 80,000 people in long-term mental health facilities. The truth is that this represents a conscious decision by society to turn care of these people over to law enforcement personnel (who are, for the most part, reality-oriented and respectful of the legitimate rights of all people) rather than non-physician (and non-scientifically-oriented) "mental health experts". But the damage has been done. In the past decade, the phenomenon of "mental health courts", judicial-system courts focused on managing these people, has become widespeard; expect continued growth (JAMA 297: 1641, 2007). One of the major moral failures in my life was not speaking up when a group of mental health professionals called a nun a "self-righteous bitch" for no other reason than saying that she preferred -- just for herself -- a celibate lifestyle devoted to caring for the sick and needy. (My course evaluation would probably have been affected adversely, but I'm still ashamed I said nothing. This happened in 1974 or 1975.) On my "psych" rotation, the physicians talked to me again and again about how frustrating it was to have to work with such screwy "fellow-professionals" who wielded so much power. Perhaps things have changed since the mid-1970's. Among my favorite articles from the 1990's was "The Government-Sponsored Revolving Door" in NEJM 333: 777 & 794, 1995. Schizophrenics on welfare learn to act crazy and get admitted while they're broke and waiting for their checks, and recover when the check arrives; and in the study sample, the typical welfare-schizophrenic's largest single expenditure was for cocaine.

It is now perfectly clear that schizophrenia is a major organic nervous system disease. Before the disease fully manifests itself, brain cells die off and brain atrophy occurs (Am. J. Psych. 155: 1661, 1998); this is already well-underway during the first episode (Am. J. Psych. 157: 1829, 2000). Certain association areas in the cortex and thalamus are hit especially hard (Am. J. Psych. 159: 59, 2002; Arch. Gen. Psych. 60: 878, 2003; counting dendritic spines Am. J. Psych. 162: 1200, 2005); the more cortex lost, the worse the outcome (Am. J. Psych. 158: 1140, 2001); all patients have gray matter lesions and enlarged third ventricles, while the more impaired ones also have white matter lesions and enlarged lateral ventricles (Am. J. Psych. 166: 189, 2009). For a review of various studies at the light microscopic level, see Brain 122(4): 593, 1999; findings differ in different studies but generally agree that there is neuronal loss and cellular disarray in the cortex, without gliosis. The loss is selective, with the dorsolateral prefrontal cortex severely involved and nearby Broca's area completely spared (Arch. Gen. Psych. 60: 69, 2003; Am. J. Psych. 159: 1983, 2002); the more that's gone, the worse the outcome (Am. J. Psych. 158: 1140, 2001). The volume loss in the superior and middle temporal gyri is by now very well-known and there is talk about its being specific for schizophrenia (Am. J. Psych. 163: 2103, 2006). A rigorous study shows a distinctive pattern of loss in the basal ganglia (Brain 130: 678, 2007). Counting dendrite intersections: Am. J. Psych. 161: 742, 2004. Further, schizophrenics have by-now-well-characterized volumetric loss of the white matter of the frontal, pareital, and fronto-parietal junctions at onset, and these get worse over time (Am. J. Psych. 164: 1082, 2007). Old studies of genetics are now giving way to the discovery of loci. Familial schizophrenia locus Science 288: 678, 2000. Neuregulin 1: Am. J. Hum. Genet. 71: 877, 2002; Am. J. Hum. Genet. 72: 83, 2003. More on the genetics: Lancet 361: 417, 2003. Update JAMA 299: 2017, 2008. Even in cases without simple inheritance, the genes obviously dominate family environment (old work on schizophrenia genetics: Lancet 1: 79, 1989; Nature 339: 305, 1989; Nature 340: 391, 1989; non-schizophrenic relatives tend to be a little-bit screwy and fill DSM criteria for schizophrenia-like illnesses Arch. Gen. Psych. 50: 527, 1993, J. Nerv. Ment. Dis. 182: 443, 1994; the adoption studies from Scandinavia, where they keep good records: Arch. Gen. Psych. 51: 442, 1994; and the neuroimaging studies show similar hippocampal changes Arch. Gen. Psych. 64: 297, 2007). The three best known loci (and all are clearly real) that confer susceptibility to schizophrenia are DYSBINDIN (DTNBP1), a protein expressed on the glutamine neurons (J. Clin. Invest. 113: 1353, 2004); altered forms run especially with schizophrenic negativism (Am. J. Psych. 162: 1824, 2005; Am. J. Psych. 163: 532, 2006). DISC1 ("disrupted in schizophrenia") and NEUREGULIN-1 (NRG1) are also major loci (update Nature 458: 976, 2009). There are conflicting results as to whether RGS4 is a schizophenia locus or not (Curr. Op. Psyc. 22: 154, 2009 -- reviews all the candidate genes and the postmortem brain chemistry.) Same or crazy, your DISC1 alleles seem to have to do with whether you're a socializer or a loner (Arch. Gen. Psych. 66: 134, 2009). KCNH2, a potassium channel: Nat. Med. 15: 448 & 509, 2009. Another locus called PCM1 runs with low orbitofrontal cortical volume and risk of psychosis (Arch. Gen. Psych. 63: 844, 2006). In twins discordant for the disease, magnetic imaging detects distinctive differences in the brains of the schizophrenic twin (NEJM 322: 789 & 842, 1990) which have been confirmed by neuropathologists (Schiz. Res. 3: 295, 1990; Br. Med. J. 305: 327, 1992; South. Med. J. 85: 907, 1992; more on twins J. Nerv. Ment. Dis. 181: 290, 1993). In monozygotic twins who are clearly discordant for schizophrenia, being the crazy twin correlates very strongly with obstetrical complications and/or problems during pregnancy or shortly after birth (Am. J. Psych. 151: 1194, 1994; there was no relation to trauma or to substance abuse; also Am. J. Psych. 157: 196, 2000; pre-eclampsia as a major risk Arch. Gen. Psych. 56: 234, 1999). In the poor nations, where obstetrical catastrophes and infantile brain trauma are more common, the rate of schizophrenia is supposedly no higher, but there's a strong link to these insults (Am. J. Psych. 151: 368, 1994). And prenatal exposure to famine and malnutrition is a strong risk factor: Am. J. Psych. 157: 1170, 2000; strong confirmation JAMA 294: 557, 2005. Currently, there's a lot of interest in obstetrical complications and/or a catastrophe during the second trimester of gestation as the added insult that makes the hereditary trait manifest itself: Br. Med. J. 305: 1256, 1992; Am. J. Psych. 149: 1355, 1992. And so forth. Schizophrenia's gotta be "multifactorial", with etiologies differing from patient to patient, and the psychiatrists had this settled by the early 1990's (Psych. Clin. N.A. 16: 269, 1993; Schiz. Bull. 19: 355, 1993). Also impressive is the finding of a striking increase in sporadic (not familial) schizophrenia following influenza A infection in the fifth month of pregnancy (Lancet 337: 1248, 1991; Arch. Gen. Psych. 47: 869, 1990; Am. J. Med. Genet. 48: 40, 1993). There is a huge excess of schizophrenics born in February and March, and in the city rather than in the country (NEJM 340: 603, 1999). An arcane statistical study of mental and behavioral illnesses that affect primarily the poor (Science 255: 946, 1992) concludes that (in contrast to depression, criminality, and illegal drug abuse), the tendency to schizophrenia causes downward social mobility, and is not the result of bad living conditions.

* Today's neuroleptic-antipsychotic drugs are potent dopamine antagonists, and dopamine-like drugs (notably amphetamine) can make a person act crazy and paranoid (but without the distinctive thought disorder of the schizophrenic). However, the old story about "high dopamine causes schizophrenia, low dopamine causes Parkinsonism, they are two ends of a continuum" just doesn't hold up to today's neuroscience; there are places in the schizophrenic's brain where dopamine is high, and other places where it is low (Am. J. Psych. 148: 1301 & 1474, 1991; striking decrease in D1 receptors in the prefrontal working-memory-processors that in turn correlates with the negative symptoms: Nature 385: 634, 1997). And the newer anti-schizophrenic drugs (clozapine, etc.) are "atypical neuroleptics" that selectively block the subset of dopamine receptors (D4) not involved in the extrapyramidal side effects of the more familiar anti-schizophrenic drugs, as well as 5HT2a receptors. Watch for more about D4 protein, which varies from person to person, and the origins of psychiatric illness: Nature 358: 109 & 149, 1992. D4 allele correlates with novelty-seeking / thrill-seeking (Nat. Genet. 12: 78, 1996). D2 claims flop: Science 264: 1696, 1994. A Beautiful Mind
A Beautiful Mind

* More plausible is the phencyclidine model for schizophrenia (ever see someone go crazy on "angel dust?"), and there's some new evidence that the N-methyl-D-aspartate receptor (blocked by phencyclidine and ketamine) is defective in schizophrenia (Am. J. Psych. 148: 1474, 1991; the ketamine model Arch. Gen. Psych. 51: 199, 1994). Not much more lately, but watch these.

The Caveman's Valentine
The Caveman's
Valentine
De-stigmatize and de-mystify this dread illness -- and explain the hallucinations not as "evidence of being crazy", but as exaggerations of perceptual errors that happen to anyone under stress (J. Nerv. Ment. Dis. 179: 207, 1991). The more the family misunderstands (and therefore criticizes) the patient, the worse the prognosis (Lancet 340: 1007, 1992); your role as educator is extremely important here. Tip: To control "the voices", try one ear plug, or a Walkman, or singing softly to oneself (Br. Med. J. 302: 327, 1991). There was a flap in the early 1990's about neuroleptic treatment causing earlier onset of Alzheimer's in schizophrenics. It's evidently not so (Am. J. Psych. 154: 861, 1997 autopsy studies.)

CHILDHOOD AUTISM (formerly "childhood schizophrenia", semi-glamorized in the film "Rain Man"; reviews Ped. Clin. N.A. 40: 567, 1993; NEJM 347: 302, 2002; Lancet 374: 1627, 2009)

    This is an inborn (usually), organic, sometimes-familial, usually sporadic disease of the brain that impacts dramatically on children's ability to imagine, socialize and communicate. The kids show intensive interest in one or two subjects, exhibit a narrow and repetitive lifestyle, lack intonation and body language, and show poor muscular coordination. You'll learn about the way these children think and behave on "Pediatrics".

    There's a consensus now that the disease arises from neuronal problems that begin before birth. By now, the morphometric differences between autistic and non-autistic populations are robust and consistent from nation to nation (Brain 128: 268, 2005; Arch. Gen. Psych. 61: 291, 2004; Brain 124: 1317, 2001). There is less gray matter in the fronto-striatal and parietal areas, smaller hippocampus, and less white matter in the cerebellum and fornices. Autistic children's brains actually average larger than those of typically-developing children (Neurology 59: 184, 2002). The neuropathology findings are also being clarified (small cells in places in the limbic system, abnormal microcolumn architecture in the frontal cortex, others: Brain 127: 2572, 2004; Neurology 58: 428, 2002), but this will be much more difficult.

    Autism often seems to have an onset sometime during the first three years of life, and this may be fairly sudden. This makes sorting out "possible causes of autism" much more difficult, and makes evaluating anecdotal evidence all the more frustrating. What's more, occasionally there IS a primary cause. Autism developing secondary to a brain tumor: Dev. Med. Child. Neuro. 34: 252, 1992. And exactly what "autism" is remains a question -- kids with common Rett's, Down's, tuberous sclerosis, etc., etc., can have "features of autism".

      * One group looked at head circumferences before the onset of symptoms; they found they were unusually small at birth, and unusually large at one year (JAMA 290: 337, 2003). If this turns out to be correct, then autism is one more programmed disease of nervous tissue.

      A finding that now seems robust is that members of occupations that do a lot of information-processing (i.e., engineers, scientists, and accounts) are over-represented among parents and grandparents of autistic children (Autism 5: 223, 2001), and to excel, as do the autistic themselves, on the Embededed Figures Test (Neuroimage 35: 283, 2007; J. Aug. 36: 677, 2006; J. Child. Psych. 47: 639, 2006; more). Most physicians will draw the same tentative conclusion that I have -- autism is polygenic, perhaps with an environmental influence, and results from homozygosity for alleles that make heterozygotes into effective student-learners-techies.

    Autism is a continuum, with the totally uncommunicative person at one end, and the odd, disliked, clumsy, loner kid who grows up to be a high-functioning, academically-inclined single adult after learning (by trial and error rather than instinct) how to relate to people (Lancet 350: 1761, 1997). In the next few years, watch for a fad for diagnosing super-nerds (young and old) as "suffering from Asperger's disease" and applying for disability privileges. See below.

    * Pseudoscientists have been particularly cruel to those who care about autistic children. Bruno ("I'm on the child's side!") Bettelheim, of U. of Chicago, assumed a priori that autism was the result of abuse and neglect, scapegoated the parents, and treated these children in an intensive, lucrative "orthogenic" milieu therapy. Of course, he never published his statistics, and he's now remembered as a charlatan (Pr. Kind. Kind. 41: 316, 1992, abstract 93109943; Skep. Inq. 24(6):12, 2000). More recent autism charlatanism has been reviewed (Dev. Med. Child Neuro 47: 493, 2005), including a $50,000/year technique that falsely claimed cures and was promoted as an "entitlement" that had priority over expenditures on teaching reading and arithmetic to ordinary public school students (J. Autism 28: 91, 1998). The study also reviews what works. (The "behavioral" approach that worked best, unfortunately, in its classic formulation made major use of electric shocks, like training a zoo animal. Asperger's kids and adults can and should be taught social skills. A few Rx's work sometimes. Beyond this, there's no miracles today or on the horizon.) Parents of autistic children are well-organized, and the government recognizes that having to care for an autistic kid at home takes a worker out of productive employment. In 2010, Missouri passed an insurance mandate for intensive treatment for every autistic kid of $40,000 per year through age 18 (i.e., four or five times the cost of an Ivy Leage or medical education); the most recent studies showed no advantage of a highly-paid therapist over supervised parents giving the intensive behavioral treatments (Autism 13: 613, 2009) or which model worked better ("applied behavior analysis" vs. "TEACCH": J. Autism. Dev. Dis. 40: 74, 2010), or whether spending just an hour a week works just as well as the intensive, super-expensive stuff (Autism 13: 93, 2009). The two decades of work on "applied behavior analysis" suggests that it does help some, but that there's a lack of scientific rigor and even controls in the studies (Behav. Mod. 31: 682, 2007). The most recent study that compared two groups (but no non-tretment group; J. Aut. Dev. Dis. 37: 1815, 2007) decided there was a slight advantage to treating the kid for 30 hr/week rather than 15 hr/week but "there was no evidence of recovery from autism".

    In the 1990's, a technique called "facilitated communication" was developed, in which the operator used the child's hand as the planchette of a Ouija board. Even if the child had never communicated or seemed to understand language, the hand would spell out elaborate stories. If the child was shown one picture and the (unknowing) operator was shown a different picture, and the child was then asked what the picture showed, the "child" would describe only what the operator saw (Ment. Retard. 31: 49, 1993 and many, many more). Gee whiz! The first commentators (1987, also J. Aut. & D.D. 21: 561, 1991) in the refereed literature knew that "facilitated communication" was bunk, but supported it because it would make the public believe that autistic kids, kids with cerebral palsy, and so forth were more like ordinary folks. In other words, politics and propaganda are more important than truth. As you might expect, the "children" often produced stories of elaborate secret sexual abuse, using the vocabulary of sleaze-pornography. Even after the above-referenced article was published, at least one parent in Kansas was sent to prison entirely on this evidence. The literature contains some accounts (notably by a group at SUNY; Arch. Ped. Ad. Med. 148: 1282, 1994) in which "the child's story was proven to be true" by the confession of the accused (no good physical evidence though); however, nowadays it is commonplace for a person accused of a sex crime, often on no real evidence, to be offered leniency in exchange for a confession ("admit you did it and accept counselling, or we'll send you to prison for life"). In 1994, "facilitated communication" (the subject of a media "miracles of healing" hype in the early 1990's) got massive negative TV coverage (for example, PBS, which finished particular folly off. Freeing several dozen imprisoned people, all convicted of child molesting solely on this evidence, will take longer. I am not making this up. How this crock happened: Child Abuse & Neglect 22: 1027, 1998 ("Its proponents' resistance to allowing the technique's validation relying on the paradigm of normal science has resulted in its broad dissemination without support", i.e., all this talk about "Thomas Kuhn paradigm shifts", "postmodernism", and so forth ruins the lives of innocent people).

    * The whole MMR-vaccine-and-autism scare resulted from a study in Lancet with obvious selection bias; the kids had been brought forward by parents who believed the MMR vaccine had caused their autism. Lancet 351:637, 1998 also includes some stuff on supposed intestinal pathology; the only "consistent" lesions are normal findings (the authors think that groups of eosinophils in the ileum are abnormal even though everybody's got them) and big lymph nodes with big germinal centers (incredibly, they made a deal out of tingible body macrophages here, everybody's got them too; no controls of course). Were they right to fast-report a possible health hazard? Wrong to rush to publication with no proper controls? Reasonable people will differ. A paper from the Wakefield group with PCR's purporting to show measles virus in the gut lymphoid tissue of autistc children, but not controls (Mol. Path. 55: 84, 2002) remains unreproduced by any other group, and curiously the group itself admitted later that its own data had been corrupted (Mol. Path. 56: 248, 2003). In Feb. 2004, the Lancet apologized for publishing the 1998 paper and revealed that Dr. Wakefield, the principal author, was actually in the pay of a legal-aid service hoping to sue over immunizations. For those who are curious about "autisic enterocolitis", I recommend the paper in Histopathology 50: 371, 2007, which reviews the problems with the work, almost all of which has come from one group; just as I did when I read the article in Lancet almost a decade ago, they point out that the original work called normal findings abnormal and weren't properly controlled; they suggest that the hyperplasia is the result of the constipation seen in autism, just as is seen in chronic constipation from other causes. More about how this particular strangeness happened: West. J. Med. 174: 87, 2001. Dr. Wakefield, who still holds out that he was right, admits that he's most impressed with anecdotal evidence, and perhaps he's actually seeing an ultra-rare phenomenon hidden in statistics (I think he could be right): Br. Med. J. 324: 386, 2002. But the fact that he apparently withheld information about a major conflict of interest will probably ruin him as a scientist. One of my cyberbuddies, a Ph.D. bioscientist who had a child with autism, is confident of Wakefield's essential integrity, other professional people have also written to me defending his genuineness and decency, and it's clear that Wakefield shows none of the signs of charlatanism that you see in most other independent thinkers. Update: In June 2006, a media claim was made that a Dr. Arthur Krisgman, pediatric gastroenterologist at NYU Med, and a Dr. Stephen Walker of Wake Forest University med school (where I did a year of training) had replicated Wakefield's findings. From the media reports, all we have is recovery of vaccine-strain measles from a group of children, without controls. We look forward to publication, peer-reviewed or not. This is a very important question, and as I've said above there may indeed be something real, despite all the politics, lawyering, and emotion. Brain diseases that are reflected only in behavior are the hardest of all diseases to study. And no one questions the devastating impact and gravity of the question. It would please me very much if an important contribution were to come from the school where I trained. Stay tuned.

    Update: Formerly portrayed in the popular press as a "persecuted genius", coverage of Wakefield has now become very hostile. Now he is a corrupt, mendacious charlatan wilfully causing the deaths of children (review of media coverage BMJ 336: 479 & 850, 2008). Although the world has plenty of rotten people, I do not believe Wakefield is one of them. Knowing people as I do, I suspect the truth is closer to "the road to ____ is paved with good intentions." I've seen nothing further on the real-science front.

    Ileal Lymphoid Hyperplasia
    How the Wakefield
    MMR business got going

    Anyway, in children reported to have autism following MMR or other immunization, there's no dose-response relationship, and no relationship to whether a batch of whatever pediatric vaccine actually contained thimerosal (ethylmercury, the supposed toxin): JAMA 290: 1763, 2003. A huge case-controlled in Britain shows no link: Lancet 364: 963, 2004. Thimerosal hasn't been in US vaccines, except for a few 'flu vaccines, since 2001, and there's been no corresponding decrease in autism (Nat. Med. 15: 119, 2009).

    The vaccines-and-autism story took a further bizarre twist when the Bush administration granted citizen (i.e., activist) oversight of vaccine safety research (NEJM 358: 2089, 2008). The index case was Hannah Poling, a Hopkins neurology resident's daughter who appeared normal at birth, but had a genetic mitochondriopathy that causes encephalitis and brain damage after common childhood infections. When this happened to the child, the family "was sure" it was the vaccines causing autism. The Bush administration decided to compensate the girl in April 2008. Stay tuned.

ASPERGER'S ("high functioning autism") is a new "disease", supposedly affecting mostly boys, running in families. Asperger's boys tend to be of normal or high intelligence, strongly focused on single topics (for example, math, chess, computers, a musical instrument, train schedules, pathology, skydiving, flattop haircuts, etc., etc.), are physically clumsy, find other people baffling, but don't commit crimes (well usually, the ones that do are refractory to treatment: Med. Sci. Law. 42: 237, 2002). Speech is rapid and lacks intonation. As kids, they are "little professors." After many social failures during adolescent and young adult life, they tend to withdraw and become odd loners. As teens and adults, they have to work hard to learn to use and read body language and to relate to others. Asperger'sseems to be real, and I predict that its study will show something about the wiring of personality. Adults with Asperger's have greatly reduced 5-HT2A receptor density (Brain 125: 1594, 2002), and differences in brain anatomy especially in the frontostriatal connections (Brain 125: 1594, 2002). Properly managed, Asperger's offers a set of unique plusses both for the individual and -- if the interests are useful -- for society.

Of all the patient-care specialties, I am most intrigued by psychiatry. Many other pathologists share my fascination with the life of the mind.

    BIOLOGICAL PSYCHIATRY is only now coming of age. Remember that different kinds of synapses may use the same neurotransmitter.

    Right now, the study of the very-common OBSESSIVE-COMPULSIVE DISORDERS is a major topic in psychiatry; watch this elucidate different types of serotoninergic synapses (Mayo Clin. Proc. 67: 266, 1992; Postgrad. Med. 91: 171, 1992; Arch. Gen. Psych. 49: 21, 1992; subtle cues to basal ganglia dysfunction Brain 114: 2191 & 2203, 1991; Arch. Gen. Psych. 47: 27, 1990, notably such stuff as visuospatial coordination; this is no surprise because Sydenham chorea produces obsessions and compulsions: Am. J. Psych. 146: 246, 1989; caudate on PET scan display before and after therapy: Arch. Gen. Psych. 49: 681, 1992). For unwanted intrusive thoughts about a past or present problem, set the business down in a cohesive form on paper. When obsessive-compulsive appears suddenly, you'll probably find damage on scan somewhere in the cortex or basal ganglia (Neurology 47: 353, 1996). Moderate catechol O-methyl transferase deficiency and obsessive-compulsive: Proc. Nat. Acad. Sci. 94: 4572, 1997. Psychological tests and scans of patients and family members (who tend to have similar, milder changes): Brain 130: 3223, 2007. Tourette's is polygenic; a locus at L-histidine carboxulase gene: NEJM 362: 1901, 2010. Sociopathy / antisocial personality ("lacking the part of the brain that feels empathy and remorse") may have an organic component, but it's elusive (Arch. Gen. Psych. 57: 128, 2000).

    BIPOLAR DISORDER is obviously genetic with several distinct syndromes and likely loci (Am. J. Psych. 160: 999, 2003; Arch. Gen. Psych. 60: 497, 2003). The genes remain elusive; Sherman's paradox seems to operate Am. J. Hum. Genet. 53: 385, 1993; the "usual suspects" include tryptophan hydroxylase, and catechol o-methyltransferase (Am. J. Psych. 159: 23, 2002). I'm not the only physician who think that the drug companies have something to do with the greatly increased frequency with which the diagnosis "bipolar" is being made recently. One kind of UNIPOLAR DEPRESSION links nicely to the serotonin transport gene (Lancet 347: 731, 1996 -- I hope no one is surprised). behavior

    ATTENTION-DEFICIT DISORDER, with difficulty focusing (even on play), is wired in the caudate and its connections to the frontal lobe (Am. J. Psych. 151: 1791, 1994; update from neuroimaging is impressive: Lancet 362: 1699, 2003). The mouse model is the knockout mouse lacking dopamine transporter: Science 283: 397, 1999.

    The big news in DYSLEXIA in 1996 was the discovery that if you help these kids distinguish different phonemes early, they do much better (Br. Med. J. 313: 1096, 1996, Child. Dev. 65: 41, 1994). As I predicted in the 1980's, the US fad to forbid the teaching of phonics resulted in a lot more cases of dyslexia (Psych. Sci. 2(2S): 31, 2001, big review, go figure); sadly, it took neuroscientists rather than people possessed of simple common sense to end this fiasco.

    Whatever else we are, humankind is the talking animal. Almost everybody has the same FOXP2 allele, which indicates it swept through the human population rather recently. This includes the Neanderthals (Curr. Bio. 17:1, 2007); any other allele causes severe deficits in speech and language (Nature 413: 519, 2001). Many people are relatively non-verbal (speaking, reading, understanding) despite otherwise normal intellectual function; there's now a few known mutations that cause recipients to be unable to use suffixes or complex grammar. Some have a lot of trouble not only being understood, but moving their faces (Nat. Genet. 18: 168, 1998 -- discovery of the SPCH1 locus, where FOXP2 is located). As a college student in the late 1960's when B.F.Skinner was dogma ("Environment is everything"), I say I'm getting the last laugh.

    PANIC ATTACKS have long been familiar to physicians. Hard findings include an exaggerated autonomic and respiratory response to infusions of lactic acid, and a rat model caused by chronic inhibition of GABA synthesis and the same vulnerability to lactic acid. The new work shows elevated levels of hypocretin / orexin in the CSF in patients with panic attacks, and that blocking the ORX-1 receptor prevents the panic attacks (Nat. Med. 16: 111, 2010).

    We await effective therapy for BORDERLINE PERSONALITY ("I hate you, don't leave me!" and more), and I wonder whether it's hard-wired or simply a lack of living skills (which are hard to teach -- and they won't learn if you tolerate their behavior). When talking to a borderline, say "I feel" rather than "you...", and avoid getting entrapped by them.

    You will hear plenty of GLOSSOLALIA (i.e., people who believe they are speaking a language they themselves do not understand) among people who are clearly mentally ill, the majority being psychotic; review J. For. Sci. 47: 305, 2002. Whether it is ever really of supernatural/paranormal origin is something you'll need to decide for yourself.

    SOMATIZATION DISORDER ("somatoform disorder" JAMA 278: 673, 1997) is still considered "all in your mind" -- I believe this is wrong. The typical patient is a low-achieving young adult with anxiety, depression, and personality problems ("borderline", etc.) However, these folks also have lots of aches, pains, and symptoms that cause substantial disability. This is a patient type well-known across cultures (Am. J. Psych. 154: 989, 1997). I predict (2007) that it will be found to have a strong organic basis and eventually an effective organic therapy. (Uh, doc, you did rule out everything else, right?)

      Of course, we all somatize to some extent, especially during difficult times. You'll be impressed by this as a physician. Much of the art of medicine is knowing when to try a workup, and when not to.

    Also watch KLEINE-LEVIN SYNDROME (spells of hypersomnia and polyphagia with bizarre behavior), or "sleep-related eating disorder". This in turn may or may not be related to compulsive nighttime icebox-raiding.

    SEASONAL AFFECTIVE DISORDER: Arch. Gen. Psych. 41: 72, 1984 (said it all; wavelength Am. J. Psych. 148: 509, 1992; the atypical antidepressant agomelatine, which disrupts circadian rhythms, seems to help: Psychopharmacology 190: 575, 2007; I was surprised that melatonin turned out to be no beter than placebo Neuropsychopharmacology 30: 1345, 2005), though some folks do use it Chronobiol. Int. 23: 403, 2006).

    NARCOLEPSY is real (Mayo Clin. Proc. 65: 991, 1990) and affects about 1 person in 5000; patients must have HLA-DR2 / DQ1 (Lancet 341: 406, 1993). They fall asleep without being able to resist, and also drop over suddenly like a rag doll from time to time without falling asleep ("cataplexy"). The brain lacks the neurotransmitter hypocretin, though this is usually not the locus (Nat. Med. 6: 991, 2000; update and additional complexity Lancet 363: 1199, 2004). Most often, the neurons that use hypocretin in the hypothalamus are destroyed (by autoimmunity, we may suppose): Lancet 369: 499, 2007.

      * Hypocretin 1 / orexin-A itself is interesting stuff... an injection reverses the cognitive impairment caused by sleep deprivation, at least in monkeys (JAMA 299: 513, 2008).

    THE TRANSSEXUAL BRAIN: Ordinary men have huge, and ordinary women have tiny, central divisions of the bed nuclei of the stria terminalis in the hypothalamus (BSTc). Among several male transsexuals (gender-dysphorics, "I'm a woman trapped in a man's body!!"), gay or straight, every one had a tiny BSTc nucleus (Nature 378: 68, 1995). More recent work confirms this even more impressively: J. Clin. End. Metab. 85: 2034, 2000. Despite the politics, some patients find their being unhappy with their sex organs disappears on low doses of medication (Aus. NZ. J. Psych. 30: 422, 1996).

    HYPERSEXUALITY seems to be in the wiring (Can. J. Psych. 46: 26, 2001), so it's not surprising that the 1990's push to define "sexual addiction" as an entity to be twelve-stepped was a total failure (Clin. Psych. Rev. 18: 367, 1998). By contrast, the common PARAPHILIAS seem to be acting-out (as common sense would suggest), either a way of dealing with your hatreds or simply avoiding the problems of being "normal". Despite the greater tolerance of (and even promotion of) "minority sexual practices" among consenting adults, these people tend to have overall poor interpersonal skills. If they find real friendship in the "alternative" community, it seems to me it's a good thing, but not the best life could offer.

    POST-TRAUMATIC STRESS DISORDER is nothing new (Sophocles' "Ajax" -- Sophocles was also a general in the army --; "Skipper Ireson's Ride", shell-shocked WWI veterans), and is serious and real, but is now highly politicized. It is most severe in torture survivors, but any brush with death or bad mistreatment (rape, child abuse) can leave a person jumpy, sleeping poorly, and suffering from flashbacks. Two accounts from physicians appear in BMJ Dec. 2, 2000. One found a deeper appreciation for how delicate and uncertain life is, and spirituality became far more important in his life. Not surprisingly, the policemen with PTSD are the ones whose "worst moment as a cop" involved seeing their own lives in danger (JNMD 194: 591, 2006). The volume of the hippocampus is lower in PTSD patients whose trauma took place in adult life (J. Clin. Psych. 62(S-17): 47, 2001, others), but not when the abuse happened in childhood (Biol. Psych. 50:305, 2001). We don't know whether this identifies people more at risk for PTSD after trauma, or whether this is due to beatings sustained to the head, or whether it is an effect of torture. A prospective study that might have helped didn't get results (Am. J. Psych. 158: 1248, 2001). There are glucocorticoid receptors in the hippocampus, and in some models, glucocorticoid excess itself (Cushing's in humans, mice given high doses) causes atrophy of the hippocampus via glutamate excitotoxicity (Arch. Gen. Psych. 57: 925, 2000; Biol. Psych. 45: 797, 1999). People who have long-term severe depression also have marked atrophy of the hippocampus (Proc. Nat. Acad. Sci. 100: 1387, 2003); interestingly, the volume of the hippocampus is apparently normal at the beginning of these patients' illnesses; another report finds normal volumes but altered shape (Am. J. Psych. 160: 83, 2003). You'll have to decide for yourself about just how prevalent post-traumatic stress disorder is in people whose "stress" seems only part of normal life; lawyers are now alleging PTSD after fender-benders, hearing off-color jokes, etc. (Science 301: 465, 2003). Today there is a strong backlash against "the medicalization of distress" (Lancet 369: 139, 2007): "There is value in focusing on adaptive coping during and after traumas. Striking a balance between a focus on heroism and resiliance versus victimhood and pathological change is a crucial and constant issue after trauma for both clinicians and society."

    Must reading (when you have time!): A chilling article entitled "Violence: The Neurological Contribution"; Arch. Neurol. 49: 595, 1992 (it is simplistic to ignore either neurology or sociology). Mice without nitric oxide synthetase are hypersexual and hyperaggressive (Nature 378: 336, 1995).

    One current big fad in psychiatry is "debriefing", i.e., they bring a psychiatrist to talk to you after any really bad experience, loads of "counsellors" after a natural or man-made disaster, in the belief that this expensive intervention prevents long term psychopathology; I can't see why it should, and now it's pretty clear that it doesn't work (Br. Med. J. 310: 1479, 1995). Curious exceptions, at least in Britain, home of the stiff-upper-lip: Br. J. Psych. 169: 405, 1996 notes the contrast between the way the system totally ignores kids who've seen their loved ones killed in car wrecks with the flood of "counsellors" who descended on Dunblane in 1996.

* NOT TESTABLE, BUT WORTH YOUR ATTENTION: The never-ending series of old and new health-and-disease crazes are within the proper scope of any introductory study of pathology. Thankfully, the "repressed memories" business is now history, though thousands of lives were ruined. The craze began in 1985, and ended in 1999. I first mentioned the epidemic in class in 1987, and it proved to be as I described. Any doubts I had were dispelled by Psychoth. Psychosom. 57: 152, 1992 (among 100 kids who saw Dad kill Mom, every one of them remembered it in detail). For a history of this epidemic of iatrogenic disease, see J. Nerv. Ment. Dis. 192: 525, 2004.

* Probably the worst feature of this and the several other phony-child-abuse fiascoes was that they tended to discredit stories of child abuse that are really true, and to transform concern over child abuse into a preoccupation of the right-wing and left-wing lunatic fringes. As usual, the real losers are the children. Litigation (especially "Ramona v. Ramona" in California) has redefined a therapist's duty to third parties, and the "therapists" are being sued like they should be. Medilegal articles: Med. Sci. Law. 39: 112, 1999, Am. J. Psych. 156: 749, 1999; NZ Med. J. 111: 225, 1998; Comp. Psych. 39: 338, 1998; Psych. Serv. 52: 27, 2001. Perhaps the turning point came when Geraldo reversed himself on "enhanced memories" in 1995, declaring it to be "cr_p". In 1999 I was pleased to meet an attorney who told me that he "makes a good living" in a practice devoted almost entirely to suing these therapists, who he tells me in his part of the country are mostly "social conservatives."

      The scars left from the child's defeat in the fight against irrational authority are to be found at the bottom of every neurosis.

          -- Erich Fromm

      I love America! No one is responsible for what they do!

          -- Karel Roden, pleading insanity in "Fifteen Minutes"

      Madness may sound romantic to teenagers or comics readers, but in the end it is just a madness.

          -- Brenda Starr, Reporter

      Confusing fantasy and reality always leads to disaster.

          -- Goethe

      The best grapes do not grow from the best soil.

          -- French wine-maker's proverb

      You deal with the madmen. All men are mad in some way or other; and inasmuch as you deal discreetly with your madmen, so deal with God's madmen, too -- the rest of the world.

          -- Dr. Abraham Van Helsing (pathologist) to Dr. John Seward (psychiatrist), in Dracula (Bram Stoker)

      MACBETH: Canst thou not minister to a mind diseased,
      Pluck from the memory a rooted sorrow,
      Raze out the written troubles of the brain,
      And with some sweet oblivious antidote
      Cleanse the stuffed bosom of that perilous stuff
      Which weighs upon the heart?

      DOCTOR: Therein the patient
      Must minister to himself.

SANE PSYCHIATRY FOR THE PRIMARY-CARE PHYSICIAN: A lot of the general practice of medicine is psychiatry. Here's how to be a good part-time psychiatrist most of the time. You get more information by asking open-ended questions and inviting the person to talk, but sooner or later you'll need to have things that are worthwhile to say, yourself. You'll need to know how to tell people things that they don't want to hear in a nice way that will not make them stop trying to change. If you actually want to help people with emotional and behavioral problems, focus on reminding them of what they can do, what's still intact (bad for any secondary gains, but good medicine), living in the present, and so forth. Today's psychiatrists give them "behavioral homework", which is simply common sense. Depression etc., both result from negative life events, and causes negative life events (J. Nerv. Ment. Dis. 185: 145, 1997). Cognative-behavior therapy actually changes the PET scan, but in complementary ways to what prozac does (Arch. Gen. Psych. 61: 34, 2003). Keep reminding people of how their screwy behavior and unrealistic attitudes ("faulty core beliefs") hurt them and those around them. Today, the scientifically-minded mental-health community seems to think that "adverse life events in childhood" are not by themselves the cause of mental illness or personality disorders (J. Pers. Disorder. 11: 34, 1997; lots more), though of course growing up in a home full of crazy people will teach behaviors that need to change in adult life. Keep watch on one's own thoughts and try to keep them from going in directions that aren't wholesome ("Zen", if you like -- though every great world-faith gives this good counsel.) Help them learn living and coping skills (i.e., explain to them how to do stuff that the rest of us may take for granted) rather than jabbering on about ("working through") their past traumas and present follies. Spending too much time figuring out exactly caused the problem can enable ongoing, harmful behaviors. Get them to confront their fears as boldly as they can. Know your issues and move forward, with guidance. And don't call this "empowerment", the 1990's grandiose-trendy word; troubled people already have the power to do plenty. To alter your feelings, alter your behavior first -- "fake it 'till you make it." Be strong. Don't do that any more. Don't run back to things that are childish. If you keep doing that, all you'll get is _____. Find pleasure and meaning in some other way.

People growing up in crazy environments acquire behaviors and attitudes that enable their emotional (and even physical) survival there, but that serve them badly in the larger world. Whatever the circumstances, one's emotional ties to one's origins are strong and these people resist changing their self-defeating behaviors. Honor their struggles to survive even as you help them leave this behind. You can help people realize why this is and that they don't need to be locked into it forever.

You may disagree with what a crazy person says, but don't argue; people who are not psychotic will come around as they realize that their thinking is no longer helpful and that they can change their behavior to deal with a world that's saner than their own childhood homes. Don't expect most people ever to understand all that may be obvious to you. But most people can learn new skills. Learn how to use a modest selection of the psychopharmaceutical agents, and use them sensibly; if a medication isn't working in two months, change it or just drop it. Remember the basics: Neurotics are troubled (lots of things upset them), personality-disorder folks are troublesome (they will upset you), and schizophrenia and most of the bad-affect states respond to medication but not to talking. Non-psychotic people with ideas that they recognize as not making sense can usually figure out, with your help, what the obsession stands for, and try to get what they really want by some more realistic route. Marriage counselling is largely the delicate art of getting the two people to listen to one another on a daily basis, and to extend basic human kindness across gender-differences (i.e., a man and a woman can learn to be nice to each other even though they cannot possibly understand each other; the other person isn't acting that way just to be hateful; "the relationship is more important than being right", and so forth). When a relationship fails, remind the person of the ways in which the former beloved / the rival are doing the person a favor. There is no physician-patient confidentiality when a human life is in danger. Please remember how unreliable memory is. Especially in the ICU on medication, people may come out "remembering" nightmares that never happened (AJRCCM 177: 976, 2008).

In my lifetime as a student of medicine, I've never seen a disease that was considered "organic" in the 1950's prove to be "psychosomatic", but I've seen the opposite many times (hypertension, asthma, stomach ulcer, inflammatory bowel disease, atopic eczema, blepharospasm, and torticollis are only the beginning; there are even genetic animal models for folks like your instructor who strongly prefer to keep our fingernails super-short). And a good psychiatrist, seeing mental illness as arising from brain, appreciates both the cognitive-insight and the pharmacological therapies (Science 275: 1586, 1997).

INTERPERSONAL THERAPY, a common-sense "innovation", was the 1990's term for psychotherapy for the financially-responsible era, where things have to be cheap and have to work. The focus was on improving people's abilities to relate to others, no matter what the circumstances. (1) Deal with any grief and loss issues, emphasizing what's still intact; (2) Solve interpersonal role disparities (i.e., conflicts over who is supposed to do what); (3) Deal with role transitions (that was then, this is now, focus on the future rather than the past); (4) Teach them interpersonal skills and make them practice between sessions. You can't make somebody love you. Talk about the other person's interests, and be a diplomat. Relationships are more important than being right. If you want a relationship to be successful, try to figure out what the other person wants, and then try to provide it. They also (5) learn to watch for goofy "I can't because..." thinking that prevents them from doing the things they need or want to do, and having them report each week. It turns out that simply letting your patients learn and practice these skills from an internet site is more effective than talking to them in a nurturing and supportive way: Br. Med. J. 328: 265, 2004. The sites were Blue Pages and Mood Gym. Here is another site I've found helpful (follow the links).

COGNITIVE-BEHAVIORAL THERAPY is now the model for psychotherapy for people capable of insight. The focus is on education, facing fears, and learning skills.

    Even for the hard cases of PTSD it seems to work. Reviewed nicely in JAMA 297: 820, 2007. "This is now." Tell the therapist in detail on tape about your worst memory (i.e., torture, war trauma, godawful abuse). Listen/watch the tape at home. Do this several times. Seek out situations that remind you of this, but are safe. You CAN survive reminders. If you use avoidant coping to avoid pain, you will be a cripple and never learn to be safe. Learn not to hyperventilate.

NON-EVIDENCE-BASED PSYCHOTHERAPY (often not even physician-supervised) remains one of the great causes of ill-health in the Western world. Providers are usually well-intentioned and it's a good way of making a living -- essentially no knowledge or real education is required. The "repressed memories" fraud has ruined tens of thousands of families; it's still widespread. The "facilitated communication" fraud sent many innocent persons to prison, as well as giving false hope to families of the extremely sick. Generally, the "therapists" focus on the past rather than the present, and reinforce their victims' sense of helplessness, entitlement and/or victimhood -- which keeps them coming back. Call me unspiritual if you want -- you'll see the tremendous harm this does when you're in practice. Whenever anybody says, "Therapy taught me to blame...." or "After years of talking abot my past with my therapist....", be aware you're dealing with someone who has been done a grave disservice.

* Physicians respect the religious beliefs of each patient, as long as nobody's getting hurt in a big way; these beliefs are a good topic for discussion. If "religion is what deals with matters of ultimate concern", one need not believe or even care about the "supernatural / paranormal" for "faith to be important." Totally sane people often report experiences with the paranormal (whatever that is). When I was an intern, a group of 15 housestaffers at lunch got into a discussion of out-of-body experience, who among us had experienced it personally, and what you told the patients who came in all worried after experiencing it; we decided it was "normal but something we don't understand"). Unlike many "spontaneous" out-of-body experiences, the one's I've read about from the experimental lab (for example NEJM 357: 1829, 2007) do not involve autoscopy or the ability to move one's frame of perception. And crazy people often report experiences with the paranormal (whatever that is; the crazies' experiences are much more diverse and atypical than the "normals"). No matter what your faith background, if you're interested in this sort of thing you may enjoy "The Interior Castle", by Teresa of Avila. She was a spunky, brilliant, non-dogmatic and often-hilarious writer from a Jewish-Muslim-Christian background. Her book, written for both cloistered and in-the-world folks, deals with trying to tell "the real thing" from dreams, hallucinations, vanity, fakery, spiritual evil, and mental illness.

OTHER NON-NEOPLASTIC NERVOUS SYSTEM DISEASES

DEMYELINATING DISEASES

Inflammatory and Demyelinating Disease
Click to see the images
Duke

    MULTIPLE SCLEROSIS is a common, dread neurologic disease in which myelin is lost successively in many ("multiple") plaques throughout the white matter.

      Although "MS" is clearly an autoimmune disease the exact pathology and pathophysiology have remained remarkably elusive. Review Arch. Neuro. 58: 1975, 2001; further review, showing that it's still basically a mystery at the molecular level: Arch. Neuro. 63: 25, 2006.

        Patients are typically young adults. "Big Robbins" points out a strong Caucasian predominance and weak familial tendency and links to certain HLA antigens (Neurology 43: 548, 1993; Arch. Neurol. 50: 256, 1993). More interestingly, adults who spent their first 15 years entirely in the tropics are almost never affected. A link to vitamin D deficiency (common rickets, or a hereditary rare syndrome in which a person has a much greater need for the vitamin -- Arch. Neuro. 65: 809, 2008) are emerging as risk factors; getting plenty of sulight and vitamin D intake as supplements are somewhat protective (Neurology 62: 60, 2004) -- this is now a robust finding.

        Some familial MS links to the gene for myelin basic protein (Lancet 340: 987, 1992 Finland, Neurology 61: 520, 2003 other caucasians), an antigen that seems to be a principal target for immunity in MS. T-cells rearranged to attack myelin basic protein are abundant in MS lesions in humans, and rat T-cells bearing the same rearrangement cause experimental allergic encephalomyelitis in rats (both Nature 362: 68, 1993).

        Although MS tends to run in families, usually it is not linked to the myelin basic protein gene (Lancet 341: 1179, 1993), and over the past decade it's been generally agreed that there are few or no "genes of large effect" involved in most MS casess (Brain 121: 1869, 1998; Brain 125: 150, 2002 -- "the Multiple Sclerosis Genetics Group" comes up with almost nothing).

        In addition to the waxing and waning of the white matter lesions, it now appears that there is an ongoing, steady loss of neurons from the cortex (Neurology 68(S3): S-4, 2007). Watch for this to be targeted by new biological therapies. Further, demyelinization of the gray matter, long-overlooked, is often extensive and correlates with fatigue and cognitive problems (Arch. Neuro. 64 76, 2007; proposed mechanism NEJM 361: 1505, 2009).

        Biopsy material from fresh MS plaques shows the oligodendroglial injury (not death) is the early injury in multiple sclerosis. They die at the center of plaques, and proliferate at the edges, and they can re-myelinate if they recover (Mayo Clin. Proc. 68: 627, 1993).

        Ask a virologist about links to viruses. The vast majority of patients are EBV-positive; Epidemiology 11: 220, 2000; now JAMA 289: 1533, 2003; molecular mimicry NEJM 349: 185, 2003; high EBNA-1 IgG titer as a teen, an aberrant response, predicts future MS risk JAMA 293: 2496, 2005 and Neurology 62: 2277, 2004; data from stored sera Arch. Neuro. 63: 839, 2006). Others occasionally still mentioned are human measles virus, herpes 6, herpes 7, and canine distemper virus.

          Support for the idea that Epstein-Barr virus is the usual culprit comes from the finding that the vast majority of MS patients are seropositive for this virus, usually at relatively high titer, and that the mechanism of molecular mimicry between myelin and EBV antigen may now be understood (NEJM above).

          * HHV6 is now being identified as replicating in active MS plaques of many (but not all) MS patients, but not in control brains. This is another bug that it's reasonable to think is ubiquitous in the tropics and less common in chilly regions. Since the main article (Science 278: 710, 1997), the work has been widely replicated, but many MS patients have no sign of HHV6.

          The mouse model uses (* Theiler's) virus, and mice that go on to get mouse-MS are those in which infection induces lasting expression of MHC-I antigens on brain cells: Mayo Clin. Proc. 67: 829, 1992.

          * A claim from anti-immunization activists and tort layers about hepatitis B vaccine and other immunizations causing MS flopped: NEJM 344: 319 & 327, 2001.

        * Nitric oxide is produced in bulk in the acute lesions (confirmed Am. J. Path. 158: 2057, 2001), and nitric oxide scavengers almost totally prevent / treat one of the mouse models (Proc. Nat. Acad. Sci. 94: 2528, 1997). Further... the active species may be peroxinitrile, which is scavenged by uric acid (!), and large registries show no patient with both MS and gout (Proc. Nat. Acad. Sci. 95: 675, 1998). Follow-up with an animal model: Proc. Nat. Acad. Sci. 99: 16303, 2002. Definitely stay tuned.

      Lesions form episodically in MS, contributing to its picture of exacerbations and remissions.

        "Sclerosis" in this context means loss of myelin and oligodendroglia, sometimes preservation of axons and massive proliferation of astrocytes. The lesions are sharply-circumscribed, yellowish or grayish (pink if very active), firm areas. The can occur anyplace in the CNS; the favorite site is adjacent to the ventricles, often symmetrically.

          Actually, axons tend to be lost specifically in the long tracts: Brain 127: 1009, 2004.

          * In a "mouse model", axonal loss seems important and at least one novel therapy addressing this is under study (J. Clin. Inv. 118: 1532, 2008).

        Microscopically, demyelination begins around the blood vessels. During the active phase, the plaques are packed with T-helper and T-suppressor cells, and presumably there is some autoimmune component to the pathogenesis (providing the rationale for immunosuppression using ACTH).

        There is some remyelinization (as you'd expect -- this is a disease with some resolution of acute neurologic defects), especially in the lesions below the cortex lesions and in early cases (Neurology 72: 1914, 2009).

          We now know that some patients remyelinate much better than others do, and they have a better prognosis (Brain 129: 3165, 2006).

        In the burned-out, chronic lesions, there are still oligodendroglia with processes wrapped around the axons, but they do not remyelinate the axons; the axons themselves appear abnormal, with thin and thick areas (NEJM 346: 165 & 199, 2002).

        * There are a few neuron cell bodies in subcortical white matter, mostly interneurons that regulate blood flow. In demyelinated areas, these neurons seem to proliferate. This is part of the ongoing mystery (Brain 131: 2366, 2008).

{01428} multiple sclerosis, myelin stain of white matter (note areas where the blue-staining myelin is lost)

{31776} multiple sclerosis
{31779} multiple sclerosis
{31797} multiple sclerosis
{31994} multiple sclerosis
{00527} demyelination in the spinal cord

Multiple sclerosis
Autopsy brain
KU Collection

Multiple sclerosis
Pittsburgh Pathology Cases

Multiple Sclerosis
Tom Demark's Site

Demyelination in multiple sclerosis

WebPath Photo

Demyelination in multiple sclerosis

WebPath Photo

Multiple Sclerosis
Pittsburgh Illustrated Case

        * Very bad MS simulates brain tumors, grossly and microscopically (Am. J. Surg. Path. 17: 537, 1993 for the distinction).

      Most (not all) cases of MS present as varying neurologic deficits that come (and go) unpredictably.

        Key symptoms of this protean disease include optic nerve involvement ("retrobulbar neuritis"; "the patient sees nothing and the doctor sees nothing"), problems with coordination, paresthesias, weakness in a limb, and problems with conjugate eye movement. Usually intellect is preserved, especially early in the disease.

        Many (not all) patients progress to severe disability as sites of injury accumulate.

          Before the new treatments, the spectrum of eventual disability was 1/3 little, 1/3 moderate, 1/3 severe: QJM 83(300): 325, 1992. MS cost an average of $35,000 per year (Arch. Phys. Med. Rehab. 74: 26, 1993).

          Today, the average cost per year is $47,000, though this varies with the level of disability. The last decade's disease-modifying drugs cost $16,000/year (Neurology 66: 1696, 2006).

      Treating MS mostly involves immunosuppression.

        Interferon-beta (Br. Med. J. 310: 345, 1995) has become standard.

        Glatiramer, a mix of short peptides made of alkaline amino acids (J. Clin. Immuno. 109: 641, 2002; Neurology 57: 731, 2001), helps in the treatment of MS, probably by simulating myelin basic protein. This along with interferon-beta Lancet 359: 1453, 2002) was the mainstay of therapy early for many years (update Neurology 71: 136, 2008).

          In fact, it seems as if interferon often keeps very-early MS from fully declaring itself: Lancet 357: 1576, 2001.

        Natalizumab, the α4 integrin inhibitor ("Antegren", "Tysabri"), seems to be a breakthrough for multiple sclerosis therapy: NEJM 348: 15, 2003. It was withdrawn in February 2005 after two reports of progressive multifocal leukoencephalopathy. Lots of people agreed with me that the risk was worth it, and the drug has been reapproved by the FDA (Nat. Med. 14: 226, 2008).

        Laquinimod, a poorly-understood T-cell immunomodulator that is very well-tolerated, passes a phase IIb multicenter European study with very good results (Lancet 371: 2085, 2008).

        Oral therapy with cladribine and fingolimod may become standard -- both are suppressors of particular types of lymphocytes (NEJM 362: 416 & 456, 2010).

        * A regimen of vitamins and carotenoids completely fails to affect the course of multiple sclerosis: Neurology 57: 75, 2001.

      * Uh... before you diagnose multiple sclerosis, it's good to be sure that you're not really dealing with Sjogren's involving the nervous system, Hashimoto's encephalopathy (draw an anti-microsomal antibody, they may be euthyroid), Beçet's, or Lyme disease.

      * A lone activist ("Nancy Markle", an internet alias; she has never come forward) is behind the flood of (fabricated) reports of aspartame causing multiple sclerosis (also lupus, brain tumors, and so forth). Anybody who's completed a college biochemistry course will recognize the bunko artistry ("Methanol causes metabolic acidosis", "Methanol, phenylalanine and aspartic acid are all neurotoxins", etc., etc.) In 1999, when "Ms. Markle" published a made-up story about the Multiple Sclerosis Foundation suing the FDA and the makers of aspartame, the MSF had to denounce her as a shameless liar; since her true identity is unknown, they could not take any further legal action. Is this a clever trick by a sugar-industry partisan? We'll probably never know. Update on the disinformation campaign: Br. Med. J. 329: 755, 2004.

DEVIC'S NEUROMYELITIS OPTICA is an aggressive demyelinating disease with retrobulbar neuritis and large lesions in the spinal cord (i.e., blindness and paralysis). The cause is an IgG antibody (NMO-Ig) directed against aquaporin-4, on the feet of astrocytes (Arch. Neuro. 63: 964 & 1398, 2006), and this is now defining in the disease (Neurology 66: 1485, 2006 -- well, now there's a paraneoplastic syndrome Arch. Neuro. 65: 629, 2008).

    There are likely to be other brain lesions (Arch. Neuro. 63: 390, 2006). The disease is no longer considered an MS variant. Unlike MS, the lesions are eosinophil-rich (Brain 125: 1450, 2002). Rituximab seems to be very effective for for Devic's: Neurology 64: 1270, 2005.

    * Devic's is one of the few suspected risks of thymectomy for myasthenia gravis (Arch. Neuro. 63: 851, 2006).

ACUTE DISSEMINATED ENCEPHALOMYELITIS ("post-infectious encephalomyelitis"; "post-vaccinial encephalomyelitis") is a rare disease that tends to follow (by a few days to 2 weeks) one of the "childhood diseases" (infamously measles) or one of the old-fashioned immunizations with lots of impurities (especially rabies). There is altered sensorium and/or movement, and both gray and white matter lesions and/or a very large lesion. Coma rapidly develops; many patients die, but most recover with little or no residual difficulty. In fatal cases, there is striking demyelinization around the blood vessels. See Ann. Neurol. 33: 18, 1993 (by Dr. Kepes at K.U.) Criteria for diagnosis are under development: Neurology 56: 1313, 2001.

Acute necrotizing encephalopathy of childhood

Yutaka Tsutsumi MD

    ACUTE NECROTIZING ENCEPHALOPATHY ("acute necrotizing hemorrhagie leukoencephalitis", now considered a severe variant of acute disseminated encephalomyelitis) is a (fortunately rare) disease that tends to follow a minor viral upper respiratory infection. There is both perivenous loss of myelin, and hemorrhage and necrosis throughout the white matter. There is a heavy, mixed inflammatory infiltrate (unlike classic acute disseminated encephalomyelitis, which lacks neutrophils).

    Acute Hemorrhagic Leukoencephalopathy
    Pittsburgh Illustrated Case

      * There is a rare familial form;this suggests that there's a genetic predisposition in sporadic cases (Pediatrics 125: e693, 2010).

      *The disease strikes down a young doctor: South. Med. J. 87: 851, 1994 (scary reading).

      Both of the above diseases are considered PERIVENOUS ENCEPHALOMYELITIS, autoimmune havoc against myelin (with type III immune injury in the severe variant). The animal model is EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS, induced by injections of myelin basic protein; the disease can also be transmitted by T-cells specifically reactive for myelin basic protein Neurology 43: 1028, 1993.

    LEUKOENCEPHALOPATHY FOLLOWING CANCER THERAPY is coming to be more widely recognized. Chemotherapy and radiation are both capable of doing serious or even fatal damage (Neurology 62: 451, 2004). The problem appears weeks to months after the therapy.

    CENTRAL PONTINE MYELINOLYSIS represents demyelinization (with axon preservation) in the central pons. The histology resembles multiple sclerosis.

      Central pontine myelinolysis can be quite extensive and render a person "locked in".

      Once mysterious (or attributed to alcohol abuse), we now believe this usually represents an unfortunate result of too-rapid correction of severe hyponatremia (uh oh, Doc....) Puzzle THAT one out! The new name is OSMOTIC MYELINOLYSIS. I have seen this lesion three times in my autopsies; in each case, it was unexpected. (* This isn't the only possible cause: see J. Clin. Path. 44: 909, 1991). Review Mayo Clin. Proc. 76: 559, 2001 (replacing sodium "within recommended limits" doesn't guarantee safety). Picture NEJM 333: 1259, 1995.

{31988} central pontine myelinolysis

OTHER METABOLIC DISEASES OF THE CNS

    SUBACUTE COMBINED DEGENERATION OF THE CORD is a curious term for a curious lesion: destruction of the myelin and eventually axons of the posterior columns of the spinal cord caused by vitamin B12 deficiency.

      Later, the brain and descending pathways are affected. This is a tragic disease to miss, since it's easy to administer the vitamin.

      The neurologic damage can be permanent.

      Now that food is supplemented with folic acid, we'll be seeing more of this. (Why?)

      Like it or not, a vegetarian (not even necessarily a vegan) who does not know EXACTLY what he/she is doing is likely to end up B12 deficient. By now, the myelopathy in these people is so well known that it's come to be called "vegetarian's myelopathy" (Int. Med. 45: 705, 2006). Moral high-ground or no, these people are endangering their health and the health of their families. The index case was a 14-year-old vegan who gave herself spinal cord disease that thankfully is caught in time: Clin. Ped. 40: 413, 2001; this was the tip of the iceberg.

      Remember that people who don't take good care of themselves and eventually can't walk may have subacute combined degeneration of the cord -- and pay with their lives (AMFJP 30: 47, 2009.)

    HASHIMOTO'S ENCEPHALOPATHY, seen in about 1% of patients with Hashimoto's thyroiditis, involves the white matter underneath the cortex. It is now clear that the pathology includes an immune-based lymphocytic vasculitis You treat it with thyroid replacement and glucocorticoids. Reviews: Neurology 49: 623, 1997. Neurology 61: 1124, 2003.

    ALCOHOLISM probably isn't good for the brain all by itself. But the most famous sequelae (Wernicke-Korsakoff) are the result of thiamine deficiencies (Wernicke's from a prolonged fast: For. Sci. Int. 47: 17, 1990).

      One-night drunkenness and chronic alcoholism have no known morphologic counterparts.

        * You'll learn in your "Psych" unit about brain-waves that are markers for not-learning-from-bad-experiences, etc., etc. Your lecturer, like possibly even some of you, had a few semi-bad experiences with alcohol as a college frosh. Your lecturer then said "To heck with this", and now rarely drinks. By contrast, the future problem drinker doesn't learn.

      CEREBELLAR VERMAL DEGENERATION (better than "atrophy"; * superior aspect is most heavily involved) is typical of chronic alcoholism, but is nonspecific.

        * "Bergmann gliosis" merely refers to astrocytes replacing the lost Purkinje cells, in alcoholism or whenever they are lost in large numbers. A keen eye can spot them sprouting upward where the apical dendrites used to be.

        Does the "moderate drinker" really get more cortical atrophy in old age? Yes! -- Stroke 32: 1939, 2001. No! -- J. Neur. N. Psy. 71: 104, 2001. Definite maybe! -- Alc. Clin. Exp. Res. 22: 998, 1998.

{17659} superior vermal atrophy

Purkinje cell loss
Alcoholic
KCUMB Team

Superior (anterior) vermal atrophy

WebPath Photo

      * MARCHIAFAVA-BIGNAMI DISEASE is a mysterious ailment, mostly affecting alcoholics and (less often) anorectics and the badly-neglected.

        The deep white matter of the cerebral hemispheres (centrum semiovale, and especially the corpus callosum) demyelinates and may even undergo necrosis.

        Nobody knows the cause. It's reported mostly from Europe, and used to be linked epidemiologically to Italian red wine. Perhaps an adulterant (arsenic?) was the cause.

        Contrary to classic teaching, the disease is often reversible with good nutrition and cessation of drinking. Great photo NEJM 351: e10, 2004.

{31986} Marchiafava-Bignami

      In suspected Wernicke-Korsakoff, look in the mammillary bodies and periventricular gray of the diencephalon for bleeds and/or gliosis.

{31763} Wernicke's
{31985} Wernicke's
{31985} Wernicke's

Wernicke's
From Chile
In Spanish

Wernicke's

WebPath Photo

      Blood alcohol levels (gm/dL)....

        0.050-0.10... happy

        0.10-0.20... drunk

        0.20-0.350... kisses mother-in-law, shoots best friend

        0.350 & up... books say "coma & death" unless you're tolerant; police often find these levels in folks who are still driving

    METHYL ALCOHOL causes necrosis of the retinal cells (ganglion cells, rods, cones). In acute fatal cases, there is cytotoxic edema and necrosis of the entire brain.

{31984} methyl alcohol poisoning. Not a pretty sight.

    REYE'S SYNDROME brains show only cytotoxic edema and perhaps Alzheimer II glia.

    CARBON MONOXIDE ENCEPHALOPATHY is often followed (in severe cases that survive for some months) by necrosis of the globus pallidus (less often, the hippocampus, Purkinje cells, and white matter).

{31751} carbon monoxide after-effects
{18751} carbon monoxide after-effects
{31742} carbon monoxide after-effects

      *One of your lecturer's friends in medical school suffered this catastrophe after saving five people from a burning building. After recovering from coma, he had major motor problems.

    KONZO results from poor people eating semi-poisonous cassava root during food shortages (Lancet 339: 208, 1992; chilling reading). Though somtimes compared to ALS, it is actually an acute, epidemic, permanent, non-progressive disease caused by necrosis of the upper motor neurons that move the legs.

      * Medical history and "natural healing" buffs: This is the same plant that the right-wing Laetrile proponents of the 1970's fraudulently claimed would prevent and cure cancer.

    METHOTREXATE ENCEPHALOPATHY causes necrosis of the white matter. Look for mineralization of the axons.

    ARSENIC POISONING produces petechiae throughout the deep brain substance.

{00206} fatal arsenic poisoning
{00209} fatal arsenic poisoning

    MANGANESE TOXICITY selectively affects the motor system, and produces parkinsonism-plus-dystonia ("strut like a rooster"). However, it does not work on the substantia nigra, but at some site farther down, probably the globus pallidus (Neurology 45: 1199, 1998).

      * The folks at KU actually have six welders sick with this, so it's not something to overlook (Neurol. 62: 730, 2004).

      * Manganese is actually an essential nutrient. In 1999, the Environmental Protection Agency started a flap about possible toxicity from manganese and/or its organic derivative (used in gasoline) in drinking water (Neurotoxicology 20: 379, 1999). Among other things, the article describes asterixis as "Parkinson-like symptoms". I'd put this in a class with the EPA's "agent orange" and "radon in the homes" pronouncements -- shouting "Fire!" where there is none. Nowadays, mainstream science dismisses the EPA as a mere mouthpiece for politicians with no ability to do, or interest in doing, real science (Nature 412: 677, 2001, more).

    WILSON'S DISEASE features copper deposition, especially in the basal ganglia.

      Wilson's is probably several diseases, and some patients have primarily neurologic disease while others have primarily hepatic disease.

    * PANTOTHENATE KINASE DEFICIENCY (PANK2) causes NEURODEGENERATION WITH BRAIN IRON ACCUMULATION TYPE I, a hereditary neurodegenerative disease that is easily diagnosed today by the iron accumulation in the basal ganglia.

      Before the cause was found, this was named Hallervorden-Spatz disease. Julius Hallervorden and Hugo Spatz were both neuropathologists who ended up at the Nazi asylum-turned-extermination-center for profoundly neurologically disabled children. The spectacle of pathologists choosing tomorrow's autopsy case from among the living must be the most disturbing in the history of pathology. Neither man was an insane monster like Dr. Josef Mengele, or a cruel experimenter like Dr. Reiter (previous discoverer of "Reiter's syndrome", convicted afterwards for his war crimes at Buchenwald), and on the evidence, both believed what they were doing was right. That doesn't make it so.

    BAD GAUCHER'S DISEASE, HUNTER'S DISEASE, HURLER'S DISEASE, SANFILIPPO'S DISEASE, TAY-SACH'S DISEASE, and NIEMANN-PICK'S DISEASE feature intra-neuronal storage of their respective products, and eventually loss of mentation.

    Also worth remembering are LESCH-NYHAN and PHENYLKETONURIA. Neither is a storage disease, but both are inborn errors of metabolism with serious effects on the nervous system.

    LEIGH'S SUBACUTE NECROTIZING ENCEPHALOPATHY (as bad as it sounds) is the result of any of at least 14 different deficiencies in cytochrome C oxidase.

    FAMILIAL MYOCLONUS EPILEPSY is several illnesses.

      "Lafora disease" features Lafora bodies in the neurons and (convenient for pathologists) sweat glands (Neurology 61: 1611, 2003). * Genes EPM2A/Laforin or EPM2B (Nat. Genet. 35: 125, 2003)

      * Another form (not the Lafora body kind) is caused by mutant cystatin (cystine protease inhibitor): Nature 381: 26, 1996.

    THE LEUKODYSTROPHIES feature bad myelin, rather than demyelinization; typically, the diseases are autosomal recessives and there is problem breaking down myelin.

      METACHROMATIC LEUKODYSTROPHY ("sulfatide lipidosis") is a deficiency in aryl-sulfatase A. The metachromasia is due to sulfatide accumulation.

{31803} metachromatic leukodystrophy patient
{31807} metachromatic leukodystrophy, gross
{31981} metachromatic leukodystrophy, micro. The blue dye stains the metachromatic stuff pink.

      * ZELLWEGER'S DISEASE is caused by a lack of functioning peroxisomes in liver, brain, and kidney.

      KRABBÉ GLOBOID CELL LEUKODYSTRPHY is a deficiency in galactocerebrosidase. There's bad myelin, with eventual loss of oligodendroglia, plus lipid-laden macrophages clustering around vessels.

        * This is yet another disease for which marrow transplantation is currently being used.

{32004} Krabbe's globoid histiocytes

      * PELIZAEUS-MERZBACHER DISEASE, mutated protolipid protein of myelin, gets discussed a lot because the severe forms are in the "diff" of a profoundly retarded baby. Contrary to "Big Robbins", many adult-onset cases are known. Remember tiger-striping of the white matter.

      ADRENOLEUKODYSTROPHY is an X-linked disease in which cholesterol esters accumulate. We discussed the whole cruel "Lorenzo's oil" business (by now, it's clear that it doesn't do what it was supposed to do) under "Adrenal gland diseases". It is now being treated with some success using bone marrow transplantation (Lancet 356: 713, 2000).

      * CANAVAN'S DISEASE, lack of aspartoacylase, features Alzheimer II glia all over the white matter. (Contrast states with elevated blood ammonia, where you see them best in the gray matter.)

    RADIATION NECROSIS of the brain sometimes occurs.

      ACUTE RADIATION NECROSIS features widespread necrosis of cells, especially oligodendroglia and the granular cell layer of the cerebellum.

      DELAYED RADIONECROSIS may occur in therapeutic-range radiation, after months or years.

        In the white matter, all of the glial cells die. Whatever vessels remain exhibit radiation-type changes.

        At the edges, look for axonal spheroids. It is likely to be worse if the patient has also taken methotrexate.

{01909} radiation necrosis

CNS TUMORS

Brain Tumors I
From Chile
In Spanish

Brain Tumors II
From Chile
In Spanish

Brain Tumors III
From Chile
In Spanish

Brain Tumors
Radiology-Pathology
Uniformed Services

INTRODUCTION

    * In 2007, the World Health Organization issued a classification of primary CNS tumors which seems to be the new standard (Arch. Path. Lab. Med. 132: 993, 2008). We will not describe every entity. In particular, tumors that are clearly of neuronal origin are uncommon, probably because neurons are post-mitotic.

    You are familiar with the old expression "malignant by location". This is especially applicable to brain tumors, which may be histologically benign but difficult to remove surgically without damaging important things.

    Risk factors for brain tumors are, for the most part, obscure. Trauma (including having been a boxer) and lymphangiomyomatosis (the lung disease) seems to be risk factors for meningiomas. You know Turcot's anti-oncogene deletion syndrome as a risk factor for gliomas, and of course, previous radiation (i.e., for acute lymphoblastic leukemia or solid cancers of the brain or its coverings) is implicated, too (Cancer 67: 392, 1991).

    Just as brain cells may be difficult to distinguish, the histogenesis of most of these tumors is seldom obvious from morphology.

    EXTRA-AXIAL tumors inside the skull are outside the brain itself. The ones to know are the meningioma and the acoustic neuroma. All the rest are INTRA-AXIAL.

    All gliomas are best considered malignant, though some are more malignant than others.

    Malignant primary brain tumors are locally invasive, and may spread via the spinal fluid ("neuraxis dissemination", J. Neurosurg. 83: 67, 1995), but very seldom metastasize to the rest of the body.

    "Psychiatric" changes are common as the first signs of a brain tumor. Frontal lobe tumors seem to produce personality changes and/or depression and/or loss of interest, while temporal lobe tumors seem to produce hallucinations and/or mania and/or amnesia and/or "panic attacks" (West. J. Med. 163: 19, 1995). Charles Whitman, the University of Texas sniper, had a glioma involving his frontal and hypothalamic areas.

    Numbers to remember: Around 1% of random autopsies includes a primary brain tumor. In adults, 70% of primary brain tumors are supratentorial. In children, 70% of brain tumors are infra-tentorial.

    * Update for pathologists on how radiologists use imaging to study brain tumors: Arch. Path. Lab. Med. 131: 252, 2007.

    * Junk science! You're heard the pop claim that cellular telephones cause brain tumors. The idea is that "radiation causes cancer"... or perhaps somebody realized that juries in junk lawsuits won't understand the difference between microwave radiation that makes cell phones work and ionizing radiation that damages the genes. In the most recent study, people who use cell phones have only 9/10 of the risk of getting an acoustic neuroma than do non-users, there is no correlation with duration or total use, and the neuroma is somewhat more likely to be on the opposite side. Neurology 58: 1304, 2002. I have already drawn the obvious conclusion.

GLIOMAS

    The common tumors arising within the brain itself. As a rule, gliomas stain positive with GFAP.

      Service pathologists are pretty good at telling them apart. One study of inter- and intra-observer variability drew the incidental conclusion that oligodendrogliomas are more common than the books say -- making up about 25% of gliomas (Cancer 79: 1381, 1997).

      * The molecular biology was worked out in the 1990's.

        p53, as you'd expect, probably heralds the transition to high grade, and not surprisingly, loss of p53 induces greater sensitivity to procarbazine (i.e., the cells do not try to repair their DNA). p53 mutation is a grave prognostic indicator in pediatric gliomas, independent of everything else: NEJM 346: 420, 2002. Prognosticating low-grade gliomas using PCNA (proliferating cell nuclear antigen), MIB-1, and Ki-67 positivity: Cancer 76: 1809, 1995; Cancer 77: 373, 1996; Cancer 79: 849, 1996; for MIB-1 see below. Much more will be discovered; right now, there's really not much in the way of prognostic biomarkers for most gliomas (J. Neuropath. 66: 1074, 2008; J. Neuropath. 67: 1, 2008.

    * The great white-knuckle call in neuropathology today is "recurrent glioma vs. radiation necrosis" (J. Neurosurg. 82: 436, 1995). Nowadays we are doing molecular typing to solve this toughest of calls: Am. J. Clin. Path. 121: 671, 2004.

    * A host of tumors with differentiation as both glia and neurons are now known. Leave these to us (Arch. Path. Lab. Med. 131: 228, 2007).

    ASTROCYTOMA / ANAPLASTIC ASTROCYTOMA / GLIOBLASTOMA

      These are the most common primary brain tumors in adults (about 80%), and are a continuum of malignancy. There is a slight male predominance.

      Astrocytomas tend to become more malignant with time, and ultimately most will probably become glioblastomas. And there is likely to be a mix when you examine the tumor.

      ASTROCYTOMAS are poorly circumscribed, whitish brain tumors. Grossly, the most common appearance of astrocytomes is "diffusely infiltrating", with very poorly-defined borders. Microscopically, they may recall protoplasmic, fibrillary, fibrous, or gemistocytic astrocytes, or grow as spindle cells or xanthoma-like cells, or (most often) present a mix.

        Protoplasmic astrocytomas are perhaps the most familiar, with the tumor cells each bearing only a few processes, and a background of little holes ("microcystic"); these tumors cells actually look like stars ("astro", Am. J. Clin. Path. 103: 705, 1995).

        * In "diffuse astrocytoma" every astrocyte in a region seems to turn neoplastic at once. In "gliomatosis cerebri" (which may be the same thing), the entire brain, especially the white matter, is invaded. I used to wonder about a virus infection; however, it's now quite clear that most of these are aneuploid, like true malignant tumors (Neurology 56: 1224, 2001; Ann. Neuro. 52: 390, 2002). Staining and possible molecular mechanisms: J. Clin. Path. 58: 166, 2005.

        Daumas-Duport grading system: Count one for each of these criteria:

          • nuclear abnormalities

          • mitotic figures

          • necrosis

          • vascular endothelial proliferation ("glomeruloid tufts").

          Grade I: Zero criteria
          Grade II: One criterion
          Grade III: Two criteria
          Grade IV: Three or four criteria

        This may already be outdated. The new World Health Organization system arbitrarily assigns a grade to each of over 100 entities. Proteomics as a way of grading astrocytomas: Neurology 66: 733, 2006. For now...

        • ASTROCYTOMA (grade II): Minimal anaplasia, rare or no mitotic figures
        • ANAPLASTIC ASTROCYTOMA (grade III): More disturbing anaplasia and/or more mitotic figures; if you see even one mitotic figure in a stereotactic biopsy, probably the tumor's best considered grade III
        • GLIOBLASTOMA (grade IV): Glomeruloid tufts and/or any coagulation necrosis and/or very ugly

{01497} astrocytoma
{01501} astrocytoma
{01503} astrocytoma
{01518} astrocytoma
{01531} astrocytoma
{15706} astrocytoma
{01504} astrocytoma
{01506} astrocytoma
{01507} astrocytoma

Astrocytoma
Text and photomicrographs. Nice.
Human Pathology Digital Image Gallery

Astrocytoma
Pittsburgh Pathology Cases

Astrocytoma
"Cystic" / "Juvenile"
WebPath Photo

Glioma
Don't worry about what kind.
WebPath Photo

Brainstem glioma
Don't worry about what kind.
WebPath Photo

Brainstem glioma
Don't worry about what kind.
WebPath Photo

Glioma
Don't worry about what kind.
WebPath Photo

Well-differentiated astrocytoma

WebPath Photo

Astrocytoma

WebPath Photo

      GLIOBLASTOMA (formerly "glioblastoma multiforme"; Arch. Path. Lab. Med. 131: 397, 2007) is a floridly malignant, variegated (many colors, many kinds of histology) tumor.

        It is the most common primary brain tumor, and the most deadly.

        It can arise from a pre-existing astrocytoma, or de novo (especially in older patients.)

          * The two pathways differ genetically. Those that arise de novo feature PTEN mutations, p16(INK4a) mutations, and EGFR amplification. Those that progress from a low-grade astrocytoma more typicaly feature TP53 mutations from the original tumor. Both acquire loss of heterozygosity at 10q25. Update Am. J. Path. 170: 1445, 2007; major review of the genetics of astrocytoma and glioblastoma JAMA 302: 261, 2009.

{01575} glioblastoma
{01576} glioblastoma, butterfly

Butterfly glioma

KU Collection

Glioblastoma
Australian Pathology Museum
High-tech gross photos

Glioblastoma
Coronal section
Wikimedia Commons

        Endothelial proliferation ("glomeruli", etc.; you can do a reticulin stain and it will make these areas stand out) and "palisading" of cancer cells around necrotic areas are typical.

        Despite massive efforts, median survival rate is about 12 months. However, around 5% survive for three or more years -- this must have something to do with the genetic profile but this remains to be worked out (Brain 130: 2596, 2007).

          * Not surprisingly, the new regimien is bevacizumab (anti-VEGF) with irinotecan (the topoisomerase inhibitor): Cancer 112: 2267, 2008).

{01582} glioblastoma
{01584} glioblastoma, dead stuff
{01585} glioblastoma
{01587} glioblastoma, gemistocytes
{01596} glioblastoma, monster cells
{17721} glioblastoma

Glioblastoma

WebPath Photo

Glioblastoma

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Glioblastoma

WebPath Photo

Glioblastoma
Pittsburgh Pathology Cases

Gliosarcoma
Pittsburgh Pathology Cases

        GLIOSARCOMAS exhibit both glial and mesenchymal differentiation; they often follow radiation (Cancer 75: 2910, 1995).

          *The old canard about their mesenchymal component "arising from the proliferating endothelial cells of a glioblastoma" was recently refuted by some simple staining studies: Arch. Path. Lab. Med. 121: 129, 1997.

      Adult astrocytomas always infiltrate the surrounding tissue, and extend far beyond the obvious tumor mass.

        Growing astrocytoma cells from the "histologically normal" tissue far away from the mass is easy: J. Neurosurg. 86: 525, 1997.

    BRAINSTEM GLIOMAS

      These are pediatric, malignant astrocytomas, which tend to involve the brainstem and turn into glioblastomas. Many cures are obtainable with radiation.

    JUVENILE PILOCYTIC ASTROCYTOMAS (J. Neurosurg. 82: 536, 1995; Cancer 72: 1335, 1993)

      These are indolent tumors that typically involve the cerebellums of children. Often they appear as a cyst with a nubbin in the wall. Even if the histology looks nasty, they are likely to grow only very slowly.

      "Pilocytic" (hair-like) astrocytes are long and thin, and "Rosenthal fibers" are typical.

      * Although these are often cured, patients grow up to be substantially less happy then their counterparts. The teenaged years, during which the young person realizes that he/she will never be able to keep up with peers in many different aspects of life, are especially stormy (J. Neurosurg. 96: 229, 2002).

{01542} juvenile pilocytic astrocytoma

Pilocytic astrocytoma
Pittsburgh Pathology Cases

Pilocytic astrocytoma
Pittsburgh Pathology Cases

Pilocytic astrocytoma
Lacking Rosenthal fibers
Pittsburgh Pathology Cases

Juvenile Pilocytic Astrocytoma
Pittsburgh Illustrated Case

    OLIGODENDROGLIOMAS

      These are uncommon gliomas of adults that typically occur in the centrum semiovale.

      Grossly, they are gray and soft, often with little calcifications (ask a radiologist). Microscopically, the tumor is sheets of fried-egg cells (* the clearing is caused by the formalin fixation), with round central nuclei and clear cytoplasm. Often there is a admixture of astrocytoma.

      Today, it is usual to test a suspected oligodendroglioma for combined loss of 1p and 19q, which confirms that it is an oligodendrogli