Clinical Central Pain

The survey continues to enlighten us on features of central pain. Thanks to all who have participated. Here are some of the discoveries which are directly attributable to participants in the survey. Many confirm what other authors have written, but others are definitely new information.

“English, which can express the thoughts of Hamlet and the tragedy of Lear, has no words for the shiver or the headache….The merest schoolgirl when she falls in love has Shakespeare or Keats to speak her mind for her, but let a sufferer try to describe a pain in his head to a doctor and language at once runs dry.”–Virginia Woolf

All descriptions of central pain are metaphorical. You cannot describe it. It is by comparison only that one can even hope to communicate to another. We appreciate your attempts to do this in the survey. We are aware of direct benefit to research and trust you will all continue to send us your comments, a place for which occurs at the end of every article. We do not publish most of the comments, but we do include them in the data.

The following propositions are statistically more likely than not to be true in central pain patients.

Spinal cord injury, stroke, and multiple sclerosis comprise more than 90% of all patients. Syringomyelia is included in SCI. AIDS neurocomplications, cancer infiltration, chemotherapy, and other possible causes are not included in the 90%.

The most common symptoms in descending order are
1)Burning dysesthesia (cold brings on this burning more rapidly than heat, but either extreme can greatly elicit the burning). Touch is also a major cause of elicited dysesthesia, and is sometimes called “mechanical allodynia”, just as temperature change is sometimes called “thermal allodynia”. The reason for the “allodynia” is that degrees of touch may be minor indeed and the temperature change necessary for pain may not even be noticeable to a normal. Therefore the dysesthetic burning, which is the end result, comes on via a mechanism of nonpainful stimulus evoking the dysesthesia.

Burning dysesthesia may be spontaneous or elicited and nearly always is both. More than 90% of CP patients have spontaneous, constant dysesthetic burning. ALL of the respondents who have burning dysesthesia also have some degree of sensory loss in the areas which burn the most severely which are nearly always the most distal areas. Those with greater percentage of the body involved in dysesthetic burning describe their suffering as correspondingly greater. Our respondents do NOT report that any medication satisfactorily relieves dysesthetic burning, which corresponds with the information posted at the National Institutes of Health webpage, but respondents do find some benefit from various sedatives, including anticonvulsants (Klonopin, Neurontin, Lyrica, etc) or from tricyclic antidepressants such as Elavil. Sedation is to be distinguished from actual pain relief, but since stress exacerbates central pain, sedation leads to less pain. Whether this can be said to be true analgesic relief is a debatable point. Nearly all of respondents with severe dysesthesia describe it as “like acid just under the skin” or with some similar term. They also have atopoesthesia, or lack of ability to pinpoint the exact location of their skin surface, where the burning is greatest.

2) Allodynia (pain from that which is not normally painful). The most commmon eliciting stimuli are touch and temperature change. Touch allodynia displays Mitchell’s delay in central injury only. Someone with peripheral nerve injury burns immediately to touch, where in pain of central origin, there is perhaps a twenty second delay before light touch elicits increased burning, ie an increase in the spontaneous burning which is already present.

3) hyperalgesia (increased sensitivity to sensation, usually with increased threshold, since some degree of sensory loss is usually present and so the sensitivity may lag detection time in normals; for example if a CP patient steps on a nail, it may drive deeply into the flesh without early awareness because of sensory loss but be more severe once it is detected) Thus, hyperalgesia only operates in the zone where sensation is available. The spontaneous dysesthesia is also sometimes termed hyperalgesia, but it is unclear what this burning is really responding to, so it may be wrong to use the word “hyperalgesia” for that.

4) hyperpathia (exaggerated pain from that which normally is painful). There is a split of opinion on whether “pins and needles” should be considered hyerpathia. Pins and needles are similar to when your arm falls asleep from pressure, but very pronounced. When circulation returns, it is painful for just a few seconds. With Central Pain the pins and needles may be present all the time (which would put it in its own category, but some CP sufferers claim the pins and needles comes on extremely readily when there is ACTUAL pressure of the type that might compromise circulation. This would suggest it is hyperpathia of the pain nerves supplying blood vessels. The nonstop tingling will drive a person absolutely nuts, but the pain is not even close to dysesthetic burning, so it gets very little attention. Pins and needles is very uncomfortable, it is the time factor which turns it into a serious matter. Hyperpathia is most dramatic to sharp touch. A needle feels incredibly sharp. This can confuse a novice examiner into thinking the sensory apparatus is doing a good job in working. They need to switch over to von Frey or Semmes filaments to do this kind of testing in CP.

5) muscle pains (also called posterior column pain or lemniscal pain–these are generally of two types, soreness or cramping) When the pain is a pulling or tearing, such as MS Hug, these kinds of pains, usually in the chest, are sometimes referred to as “level of injury” pain. Muscle pains elsewhere are usually more crampy and not as likely to feel as if the muscle is being torn.

6) lightning or lancinating pain (these are identical to the lightning pains of neurosyphilis. Neurosyphilis was known by autopsy so lightning pains have been linked to the posterior columns of the cord for many years, and recent studies with eletrophysiologic testing such as evoked potentials confirm that lightning pains are also linked to posterior columns in CP. Lancinating (the British prefer this term) pains usually travel toward the brain, with the shock lasting anywhere from inches in the face to a foot or more in the legs, and with careful evaluation can sometimes be associated with a fasciculation at the origin–consequently these pains are thought to be carried in the posterior columns) Lightning pains, like other posterior column pains, may respond to opiates, also respond more readily to anticonvulsants such as Neurontin or Lyrica, and may diminish over time.

7) Visceral or peristaltic pain This is manifest as nausea, often exacerbated by movement or bumping, a sense of fulness or bloating and can be very severe. It is difficult to treat. It is not to be confused with pain on passing flatus or feces, which is simply hyperalgesia or hyperpathia from distention of the anus. Since the patient may have little or no sensation, they may be incontinent through lack of sensation alerting that stool or gas is present at the rectum, and have no awareness of the need for control, yet still have severe rectal pain just before the event happens. Many complain that this pain is severe enough to interrupt sleep frequently.

8) Loss of working memory. We are not entirely happy with this term, since we know the standard tests psychologists use for “working memory” and we know our memory loss is slightly different. We prefer “inability to multi-task, distractability, inability to hold a thought” “inability to file away current information if other information is intruding”, but we await more specific terms to describe the working memory loss in central pain. In some respects, CP nerves actually have improved memory, such as in the palindromes of leftover touch which Central Pain subjects display (see Mayo Clinic paper by Gilbert Gonzales using SEARCH)

9) Loss of identity. After several years pass, the person cannot remember normal touch, cannot remember not hurting, cannot remember who they were and cannot skillfully manage their lives in any way that is familiar. They have little in common with their closest friends and loved ones. Except for what little they may still have to offer, they feel unwanted, a condition that inevitably leads to severe depression. They do not know if they are making wise choices, and often feel there are no wise choices, since no choice can remove them from the terrible burning, their fatigue or sense of desperation.

Emotional Problems

The comments in the survey make clear that we still have a very long way to go in educating the public on the severity of central pain. Unfortunately, stories of “painless soldiers”, mind over matter, and pain myths make life miserable if anyone attempts to describe their central pain. We have attempted to trace down these misguided ideas about pain to our surprise, find that many of them date back to World War II, and the work of the famous author Paul Brand (author of “Pain, the Gift Nobody Wants). Clearly, those who subscribe to the various myths have not read Brand. He was a famous hand surgeon, who spent most of his life studying the complete lack of pain in lepers in India at Vallore hospital. His later life was at the University of Washington, where he was highly honored, including by Everett Koop. Despite his highlighting the inevitable injuries which occur when there is loss of pain sensation, and his pointing out the emotional pain when one is painless, Dr. Brand was an admirer of Patrick Wall, who was the originator of the database at painonline. Brand frequently deferred to Wall and Melzack in describing the basic mechanisms of pain. These two Englishmen attacked pain from opposite sides. Brand, from the injury which pain loss causes (and thus putting in a good word for pain) and Wall from the realization that neuropathic pain is entirely different from normal pain and that it is a condition which urgently needs a treatment. Both were men of immense compassion and had saintly charitable natures.

Brand’s work sheds light on how to deal with pain even though he was focused on the lack of pain. Originally, Descartes came up with the idea of how pain operates by taking a tour of a French amusement park. In it was a tile, which was rigged to a spout. If you stepped on the tile, you squirted yourself in the face with water. Descartes had an “epiphany” where he concluded pain must be the same way, a simple, hard wired system. Of course, that was a very long time ago, and no one subscribes to “Cartesian” pain ideas any more.

Pain is a complicated cascade of chemical reactions, leading to acids in the perineural area. In neuropathic pain, the controls on the acids and the channels which are affected by them are injured as the nerve is injured. Repair attempts by genes in the neurons are counterproductive since the increased activity only leads to unmodulated inappropriate outpouring of pain exciters, which can make life a true hell. One person said “Central Pain has to be even worse than hell, because damned spirits have no bodies and could therefore suffer no physical pain, only emotional pain, and with CP you get both.”

Severe central pain is the worst pain state known to man. Without hesitation, those who are paralyzed describe the central pain as more disabling than the paralysis, and those who are incompletely paralyzed would be willing to accept complete paralysis if the pain would only end. Severing the cord may give temporary relief, but as the cut ends sprout in the attempt to heal and grow, the process returns and nerve injury pain returns, usually present at even a higher level of cord injury.

Although Dr. Brand was the original source of the painless soldier story, the second half of his tale is nearly always omitted, for reasons that are unclear.

Dr. Brand reported on a soldier who was wounded so badly he could not walk. With his wounds he was able to crawl through dangerous gunfire and bravely drag to safety his comrade who could not move. During this episode, with repeated hits, he experienced no pain at all. This level of heroism was reported and repeated throughout Britain and even the entire world. Others began to have similar stories to tell. It was trendy to say one had been shot and felt no pain. It sill is. Human bravery has grown to mythic proportions over this kind of event. Those who hurt tend to remain silent for the “cowards” they would be considered to be. However, medics during WWII, gave out enough morphine to wounded to soldiers to float the Queen Mary and have no delusions about who was hurting or what caused it.

The problem with the story is that Brand took care of this patient after he reached Leavesdon evacuation hospital. His injury apparently became neuropathic, at least for a time. Dr. Brand describes his entreaties, his pleadings, and his tears in the attempt to avoid having therapy. He was terrified beyond belief and used every verbal device to avoid being hurt further, to persuade his caregivers to leave him alone. What was the terrible thing this famous, brave, soldier was begging to be spared? An ordinary penicillin shot. He claimed he was now in too much pain to endure an injection. Brand quotes Jake as saying “I have only one thing to think about all night in bed: that needle. It’s huge, and when the nurse comes down the row with her tray full of syringes, it gets bigger and bigger. I just can’t take it, Dr. Brand.”

Actually, Jake is not paradoxical. Anyone with severe hyperpathia can well understand what he was talking about, but even Dr. Brand could not figure this out. He tended to view it as some kind of delayed emotional reaction the soldier had suffered or an environmental thing, but today we recognize the hallmarks of nerve injury pain, and what is known as hyperpathia.

This author was diagnosed by Dr. John Bonica. When that great doctor did a simple pinprick exam, the tears sprung out and Dr. Bonica was begged not to repeat the stick. The little safety pin felt like a huge, long needle. I had never noticed this because loss of sensation meant no one had tested me with a pin before, only cotton balls. Immediately Dr. Bonica recognized central pain, when it had not even occurred to others.

Dr. Bonica himself had suffered from long years of pain and rather than making him disdainful of the pain of others, it made him more compassionate. His pain was too severe to go around telling people how brave he was and how much pain he had endured. That is typical of the really severe cases–they know they have been broken by pain and do not hold themselves up as an example.

Dr. Brand even describes hiw own routine with neuropathic pain. In those days, they didn’t have capsaicin, so Brand’s mentor, Tommy Lewis (author of the 1945 bestseller “Pain”), would put on a compressive blood pressure cuff, and then have Brand squeeze a rubber ball. The injury to the nerve through loss of circulation soon made this unbearable due to burning pain, and Brand always remembered how Lewis pushed him to the limit in an embarassingly short time. This kind of pain is known today as PROTOPATHIC pain, the burning which is the last sensation to leave when a nerve is injured or compressed. Protopathic burning is the most durable sensation in our nervous system. When all else is gone, we can still feel that. Central pain dysesthesia is unending protopathic burning. The chemicals of temporary nerve injury have become permanent. The same happens in lab animals who have chronic compression nerve injury, whether of peripheral nerves or of the cord. If in the cord, we term it CP, if of the peripheral nerves, it is PNI.

Although you must endure the questionable psychological theories of Dr. Brand (he admits he has never even been in a pain clinic and is no expert on pain), his book on Pain is well worth reading for the inspirational value. You will be able to endure your pain a little better for having read him. and with central pain, ANYTHING that can give you a little better attitude is worth reading.

Just as Dr. Wall urged that central pain NOT be discussed in theological terms because it tended to diminish research, Dr. Brand, although a deeply religious person, had little use for those who thought pain was God’s will. He saw it instead as necessary for survival and marvellously organized to prevent injury. He declared that God was “not in the business” of handing out specific illnesses to people personally.

Dr. Brand and Dr. Wall, may they rest in peace. We suspect they have held more than one conversation with the saintly Dr. John Bonica.

“He jests at scars who never felt a wound”–Wm. Shakespeare, Romeo and Juliet