The longer we treat pain the more questions keep coming up. After many years of seeing patients with no serious tissue damage or damage that has healed quite well, and suffering from disabling pain demands attempted explanation. It is our view that these patients have normal brains and are not mentally ill.
So are they imagining this pain? That is unlikely, since pain is almost as unpleasant as suffocation and to imagine either would be potentially harmful at most and at least highly unpleasant. If we really could imagine pain, as soon as it started to bother us we would put it out of our mind immediately. We cannot do that. Yes, I agree there are some very special individuals that seem able to shut out pain (shamans and yogis) but most mere mortals cannot. We know there are forms of brain training (ACT, CBT, guided imagery to name some) can reduce the angst associated with pain but the pain usually persists.
First we need to try to understand why pain is so powerful and so insistent that it be felt. The answer is millions of years old. Up until about 200 million years or so ago, organisms responded to harmful events and physical threats by reflexively pulling away using the sensors, nerves, and muscles endowed from billions of years of plodding evolution. The organisms that were the best at this got to pass their genes on in the process of natural selection and the next generation got a tiny bit better at staying out of harm’s way.
Two hundred millions of years ago the earliest mammals got a neocortex, a new addition to the old brain. It was capable of doing more than responding. The neocortex could feel. It had consciousness. Consciousness provided a greater range of behavioural responses and hence gave them a selective advantage – meaning their genes had a leg up on the competition.
Since damaging stimuli needed to be avoided, the sensation we now call pain evolved to be highly unpleasant and as close as biologically possible to the actual events (cut, burn, break, etcetera). Pain experience gave mammals many advantages. Mammals could learn and avoid injury (pain). Mammals could teach their offspring to avoid injury (pain). Pain could also allow wounded individuals to protect the wounds until healed when the pain would go away.
Mammals, and eventually us, needed pain to get where we are and as such the mechanisms within our nervous system are robust and likely redundant (more that one way to experience pain). Our brain knows that pain is good for survival!
Evolution probably also created a spectacularly powerful way to block pain immediately following injury. It is frequently stated that there is no biologic value to stopping pain in the dying prey mammal. What is missed in that assumption is actually quite simple. Many more animals are wounded than killed in predator-prey interactions. If pain were allowed to immobilize the animal they would all become lunch. At the same time if pain were not highly unpleasant animals would have far less motivation to flee or flight. Intense stimuli from severe damage have developed the capacity to temporarily stop the pain and allow the injured animal to flee, go to ground and heal. The better this was the more mammals could live to breed again.
We refer to this as ‘shock analgesia’ and it is powerful. Last summer I fell during a race and fractured my second rib (if you know much about trauma the significance of a fracture first or second rib will be clear). I got up and finished the race unaware of the seriousness of the injury. I spent the next two weeks virtually unable to rise from my bed. Had I fallen being pursued by a sabre-tooth tiger I would have been able to continue fleeing!
This pain control system is exploited by pain medications like duloxetine, tramadol and tapentadol.
So then, ‘why pain?’ when there has been healing in some people? I feel the answer is simple but the solution difficult. Pain becomes conscious when a specific pattern of signals reaches this neocortex (the new part of the mammal brain). After trauma and disease tiny nerves leading to the brain often do not heal perfectly. The neocortex is there to protect us so our genes get reproduced and it relies on nerve signalling. This is a powerful system. After injury nerves will send imperfect signals because of damage. The wily, protective brain seeing an abnormal signal may remember the initial injury or simply decide it is pain and yet there is no new injury of disease. If fact it may do this even when the limb is not even there-so called phantom pain.
The wily brain, of course keeps telling us (consciousness) our back, neck, ankle, shoulder, whatever is injured when in fact it is not or at least it is healed as much as it is going to heal. If this is the reason we have pain and we get an operation to ‘correct, the back, neck, ankle, shoulder ,whatever it will fail and we will be upset with the surgeon.
When you see your doctor with this kind of pain you are often told there isn’t anything wrong with you. If you injure your back and six months later you still have pain your back is not likely ruined even though those unhealed nerves are still telling your wily protective brain something very different.
Most patients with chronic non cancer pain are really in this group- real, not imaginary, pain but no real ongoing injury. Pain converted from protector to tormentor. Jekyll to Hyde. Pain of no biologic or survival value. This is hard pain to treat but if your doctor looks hard and cannot find a treatable cause and enough time has passed after the injury to allow healing you will have a better outcome when you understand this and learn to see the pain in this way. You are not a malingerer.
gcwardell 