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A book by
William H. Calvin
UNIVERSITY OF WASHINGTON
SEATTLE, WASHINGTON   98195-1800   USA
The Throwing Madonna
Essays on the Brain
Copyright 1983, 1991 by William H. Calvin.

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Scanned, OCR'ed, and webbed -- but NOT proofread (14 Jan 97)


WHEN THINGS GO WRONG

"Anybody who thinks this is all about drugs has his head in a bag. It's a social movement, quintessentially romantic, the kind that recurs in time of real social crisis. The themes are always the same. A return to innocence. The invocation of an earlier authority and control. The mysteries of the blood. An itch for the transcendental, for purification. Right there you've got the ways that romanticism historically winds up in trouble, lends itself to authoritarianism. When the direction appears."
A San Francisco psychiatrist
talking about the 1960s drug culture,
quoted by JOAN DIDION in
Slouching Towards Bethlehem

Man's destiny is to know, if only because societies with knowledge culturally dominate societies that lack it. Luddites and anti-intellectuals do not master the differential equations of thermodynamics or the biochemical cures of illness. They stay in thatched huts and die young.

EDWARD O. WILSON, On Human Nature

Yossarian shook his head and explained that deja vu was just a momentary infinitesimal lag in the operation of two coactive sensory nerve centers that commonly functioned simultaneously.

JOSEPH HELLER, Catch-22

11

What to Do About Tic Douloureux

Most chronic pains
just wax and wane.
Low backs and arthritis
continue to spite us.
Try what we might,
there's no end in sight.
But the worst pain of all
has now taken the fall --
for we know what to do
about tic douloureux.
ANON.
The worst pain in the world, say the sufferers of tic douloureux. But it is totally benign--no one literally dies from this disease, if you don't count the car accidents and suicides engendered. For it is a false alarm, though one impossible to ignore. And one of the most fascinating of medical detective stories.
      But, if you must suffer from a chronic pain disorder, these sudden electric shock-like pains in the face do have a singular virtue: medical science can make them go away, permanently.
      For no other chronic pain disorder--think for a moment of your friends with low back pain or arthritis--is there either a good pill or a good surgical track record. But for "tic," there is a good medical treatment--daily doses of an antiepileptic drug called carbamazepine work well in half of the sufferers-- and there are two excellent surgical treatments with even better track records.
      Given that perhaps 20 percent of the population suffers from a chronic pain disorder of lesser degree, there must be a lot of people around who would gladly trade their lesser but untreatable pains for this "worst" pain, given how readily it can be turned off.
      These effective treatments for tic douloureux are a recent thing, payoffs of centuries of trial and error and decades of modern medical research. Benjamin Franklin's diaries from his years as ambassador to France record the primitive nerve destroying treatments attempted 200 years ago by the leading physicians of Paris. And even today, you have to live right to get rid of your tic pain--live right close to expert medical and surgical care.
      For the patients seen by the experts have usually been through years of ineffective treatment, and thus needless suffering. Some may have had most of their teeth pulled out, on the theory that a pain in the jaw that feels like a dentist's drill hitting a nerve (but continuing full-blast for many seconds) might be due to bad teeth. Many dentists cannot recognize the hallmarks that distinguish tic douloureux from more ordinary pains, besides they frequently find dental problems anyway and are often faced with an insistent patient who demands radical treatment for an out-of-this-world pain, who will shop around until finding a dentist who will pull his teeth.
      Ignorance is expensive. And in this case, excruciating. There isn't a cure for every pain problem--indeed for very few of them--but tic douloureux is now happily an exception, provided problems of education and availability can be overcome.
      This litany of facts about tic douloureux, this bundle of contrasts, is only the tip of the iceberg. Neurological researchers talk of tic as one of the greatest of medical puzzles, with all of the elements of a proper detective thriller. There are dozens of tantalizing clues scattered about, some of them misleading, many exactly analogous to the classic clues of the murder mystery. Except that the story lacks a proper ending--no one yet knows for sure exactly how the dastardly deed was done. But surely such a fascinating, well-defined puzzle might, if solved, not only explain the tic pains but some other less well-defined chronic pain disorders as well.
      The most important clue, appropriately enough for a good detective mystery, is the trigger. While tic pains occur like lightning, something usually triggers them. Shaving, or stroking a mustache, may set off a pain that lasts for many seconds. The triggering sensation is never, in itself, painful. Here is a pathophysiological version of the Sherlock Holmes dog-that-didn't-bark clue: Using a magnifying glass to focus light rays to heat up the skin will not trigger the tic pain, though causing a normal "ouch" pain. To trigger the tic pain, one must press on the skin receptors that respond to hair movement or light touch. Sometimes, just moving a single hair will be the trigger.
      And here is the crime-by-remote-control gimmick: The trigger need not be in the same place as the subsequent pain is felt. Touching the mustache may trigger a bolt-of-lightning sensation felt beneath the beard along the jaw. Or perhaps over the eyebrow in other patients.
      Besides these fascinating clues involving the trigger, there is the disappearing act. Tic pain is either present in great intensity, or it is absent. Unlike other chronic pains which wax and wane in intensity, tic pains are like a light switch that is either on or off. In between attacks, tic patients may be living in terror of the next visitation, but they are otherwise pain-free. The neurologist is hard-pressed to discover anything abnormal. There are typically no numb areas of the face or mouth--except as a side effect of a prior surgical treatment--and only a few patients report abnormal sensations, such as flickering, nonpainful crawling sensations here and there.
      Stranger and stranger. And what is one to make of the fact that even powerful painkillers are totally ineffective against tic--yet one of the antiepileptic drugs is quite effective? Carbamazepine (trademarked as Tegretol) actually is effective in three out of four patients, but one of those three will be unable to put up with its side effects. Perhaps tic is an epileptic seizure confined to the trigeminal nerve?
      Among the traits that allow the detective to locate the criminal is the modus operandi (does he stick to certain neighborhoods?). The other name for tic douloureux is trigeminal neuralgia, because this disease is peculiar to the trigeminal nerve's territory: tic pains are never felt outside the parts of the face served by the three branches of the trigeminal nerve; they seldom cross the boundaries into regions served by other nerves. This strongly suggests that the problem is located in the trigeminal nerve itself, not back in the brain where the trigeminal fibers rapidly become intermingled with those from other nerves. There are, however, analogues to tic douloureux that restrict themselves to other nerves of the head, such as the glossopharyngeal nerve. If anything, this rare glossopharyngeal tic is worse than the usual trigeminal version, because the trigger zone and the pain are both inside the mouth and throat. Eating or drinking may trigger the attack. Which tends to put one off one's food (remember the Garcia phenomenon from Chapter 5?).
      Tic douloureux isn't rare. Just ask around in a retirement community where everyone is over 50 years old, and most people will know a sufferer, just as they will be up on the latest in cataract surgery and face lifts. While it is occasionally seen in the young, tic douloureux is commonly seen with advancing age, along with hardening of the arteries and such.
      The detective story even has a false ending--a partial resolution which, like a cryptic confession in a suicide note thirty pages before the end of the book, only serves to deepen the mystery remaining. It is now apparent that most cases of tic douloureux, perhaps 90 percent, are due to the roots of the trigeminal nerve being damaged by a misplaced artery. This occurs after the three major branches of the trigeminal have merged together and are about to enter the brain stem. The neurosurgeon opens up the back of the head and uses a microscope to look down the side of the brain to the floor of the skull. Blood vessels hang here and there in the fluid-filled space between brain stem and skull, often dangling down from the overhanging cerebellum. With age, these small arteries become stiff and tend to elongate.
      In patients with tic douloureux, one of these elongated arteries will be found compressing the nerve roots from the face, pounding away with each heartbeat. Sometimes it is a loop of the basilar artery coming up from below, sometimes it hits from the side, often it is a cerebellar artery dangling down from above. Where it hits the nerve roots tends to determine where the pain is felt in the face. Looking through a microscope and using long-handled instruments, the surgeon gently dissects away the filmy membranes that bind the artery to the nerve roots, freeing up the artery. Like a fire hose under pressure that has been freed from an obstruction, the artery will spring into a new position when released from the attachment to the nerve roots. This relieves a constant tension tending to pull the nerve roots away from the brain stem. Some spongelike material is inserted between artery and nerve roots to act as a shock absorber. Within a few days, the lightninglike tic pains will usually cease forever-- the cure rate being about 85 percent.
      This bit of delicate surgery reveals the typical cause of tic douloureux (though there are also some rarer causes such as multiple sclerosis which must be ruled out before the operation is attempted). Moving the artery effects a real cure. There is also another useful operation which, while not removing the cause, does usually stop the pains for a few years. One sticks a needle into the nerve just where it enters the skull and destroys part of the nerve with radio-frequency heating for a minute or so (just "poaching," not frying, the nerve, using temperatures of 75-80°C). While a thumb-width away from where the pounding artery is located, the site of destruction is effective because the nerve roots die all the way back into the brain. This does get rid of the pain but at the price of losing some of the nerve. In the hands of a skillful surgeon, however, about two out of three patients will lose only pain and temperature sensation in the painful region of the face-- light touch will be okay but pinprick will feel dull. (Why? The small nerve fibers carrying pain and temperature sensations are more susceptible to destructive heat than the larger fibers.) Some patients prefer this operation as it is quickly done under local anesthesia and laughing gas, in an x-ray suite rather than an operating room. The artery-moving operation is a full-scale, general-anesthesia job--but it does get at the root cause, and usually leaves the nerve working properly.
      So the culprit is the artery, located somewhere where it shouldn't be (similar misplaced arteries, impinging upon other cranial nerves, cause hemifacial spasm and some cases of tinnitus, vertigo, and high blood pressure). But we are all still somewhere between the pseudo-conclusion and the real one, still having the problem of figuring out how the deed was done, step by step. How does the artery manage to cause a lightninglike pain? After all, the pain doesn't pulsate with the heartbeat-- indeed, there is usually no sensation between tic attacks. Why antiepileptics? Why, why, why?
      The mystery deepens. What mechanism will allow the mustache trigger to set off the beard pain? How will painful heat manage to avoid setting off the tic pain? Will such a step-by-step solution of the tic pain mechanism enlighten us about low back pain or perhaps epilepsy? Tune in for the next exciting episode. . . .


To save you from emailing me: The standard advice I give to patient inquires about trigeminal neuralgia is:
There are now many neurosurgical centers able to effectively diagnose and treat it. See the Trigeminal Neuralgia Association Homepage. If you need a second opinion, contact the neurosurgery department (or the pain clinic) at your nearest medical school for a referral. A useful account of tic surgery is:
      Shelton, Mark L. Working in a Very Small Place. Viking (1989).


The Throwing Madonna:
Essays on the Brain
(McGraw-Hill 1983, Bantam 1991) is a group of 17 essays: The Throwing Madonna; The Lovable Cat: Mimicry Strikes Again; Woman the Toolmaker? Did Throwing Stones Lead to Bigger Brains? The Ratchets of Social Evolution; The Computer as Metaphor in Neurobiology; Last Year in Jerusalem; Computing Without Nerve Impulses; Aplysia, the Hare of the Ocean; Left Brain, Right Brain: Science or the New Phrenology? What to Do About Tic Douloureux; The Woodrow Wilson Story; Thinking Clearly About Schizophrenia; Of Cancer Pain, Magic Bullets, and Humor; Linguistics and the Brain's Buffer; Probing Language Cortex: The Second Wave; and The Creation Myth, Updated: A Scenario for Humankind. Note that my throwing theory for language origins (last 3 essays) has nothing to do with the title essay: THE THROWING MADONNA is a parody (involving maternal heartbeat sounds!) on the typically-male theories of handedness.
AVAILABILITY poor.
Many libraries have it (try the OCLC on-line listing, which cryptically shows the libraries that own a copy), and used bookstores may have either the 1983 or the 1991 edition.

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