Dr Sarah Fox - Chambery 2010
I have learnt about pain in a number of ways I have my own personal 30 years’ experience of chronic pain since my teens, I have been involved with support groups around the world since 1998, I have worked in a Pain Clinic and done a PostGraduate Diploma in Managing Pain. More recently I have worked in a Pain Rehabilitation service and I currently work with elderly people with chronic pain and mental illness, including dementia. I also continue to be involved with a number of organisations supporting people with Adhesive Arachnoiditis around the world, as well as Arthritis Care in the UK.
In such a brief talk, one can only hope to scratch the surface of this complex topic.
What is pain for?
Pain is a basic survival mechanism, and has a protective, life-preserving function. It is an aversive message, shouted, not whispered, designed to grab attention and provoke an active response to avoid the stimulus. It is set down in memory to prevent future damage, so it is also a learning experience.
Contrary to popular belief, pain is not necessarily a signal of damage, it is a signal of DANGER.
The International Association of Pain (IASP) definition of pain is:
“An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”
Acute pain and chronic pain
Whereas acute pain tends to signal damage, thereby focussing the attention, leading to avoidance and recovery behaviours, chronic pain is not in itself useful for survival. It may lead to changes in mood and a variety of behaviours, some of which may be adaptive, but often they are maladaptive.
Chronic pain, which, by definition, is “any pain, whatever its origin, that recurs or persists over an extended period of time and interferes with functioning.” (Burkhart, 1990), is multifaceted and impacts upon many aspects of our lives: physical, emotional, behavioural and social.
However, attempts simply to define chronic pain as that which persists after the normal healing time may be misleading. Pain may occur without evidence of tissue injury, or minor injury may cause major, seemingly disproportionate, disability. Phantom limb pain is an example of chronic pain without ongoing tissue damage (or even the presence of the perceived source of the pain).
Pain pathways are very complex. Our understanding of the nervous system is much like our knowledge of outer space; we are learning new things all the time. Until relatively recently, the nervous system was thought to be fixed: if damaged, it was not repairable. Now we know that it has a feature known as plasticity, which means things change, often dramatically and within a short period of time. For instance, at a spinal level, pain can be ramped up or damped down. There are descending signals from the brain down, as well as the ones going up to the brain. The body is now thought to be represented by a ‘neuromatrix’ in the brain and after a while, pain can become ‘hard wired’ into it.
Pain doesn’t equate with the amount of damage: you can have pain without any damage. For instance, in phantom pain (which can come from any removed body part, not just limbs), the pain after amputation tends to mimic exactly the pain before and the greater, more long-lasting the pain before, the greater the risk of phantom pain. This is because the neuromatrix still has the information about the missing body part.
Peculiarities of pain
Research has shown that in about a third of victims of severe injury (such as in battle), the person has a period of no pain whatsoever from their injury. It does kick in some hours later, but at the time of the injury, there is no pain. Survivors of shark or lion attacks also describe this phenomenon. It is unclear why this happens, some people suggest it is a protective mechanism to avoid suffering, but it is also possible that in the case of catastrophic injury, perhaps the brain interprets the situation as irredeemable and therefore there is no point in pain triggering the survival mechanism of flight, fright or fight.
The concept of “Total pain” was proposed by Dame Cicely Saunders, founder of the Hospice movement in the UK, who described a wide gamut of other factors besides sensation of pain which go to make up the whole experience.
Another way of thinking about pain is imagining it as a stone thrown into a pond: it causes ripples that have a much wider effect than the size of the stone.
“Chronic pain… is an illness of the whole person and not a disease caused by the pathological state of an organ system.” American Medical Association
Chronic pain syndrome
Chronic pain has widespread effects and is now being recognised as a condition in its own right. These include symptoms that don’t appear at first glance to be related to pain: such as being short of breath, palpitations, sweating. Of course, there are also emotional effects.
Pain and anxiety
Pain and anxiety go hand in hand. The link is not only logical, it is also biological. This is because pain and fear (anxiety) share chemical transmitters and pathways, and are processed in similar parts of the brain. The limbic system in particular is involved with the emotional impact of pain.
It can be helpful to think of having chronic pain as being constantly under attack, as if you are under siege conditions. The fight, flight or fright response kicks in and this has diverse effects. Imagine if you will, how you would feel if you were being chased by a sabre tooth tiger: your heart would be pumping wildly, you would be out of breath and you would feel AFRAID! Fear (anxiety) in these circumstances is not under your conscious control, it is a basic, atavistic response.
The meaning of pain
How pain affects us depends on a number of individual factors, both nature (genetic disposition) and nurture (e.g. memory of previous pain experiences). If a room full of people all suffered an identical injury, they would each have completely different experiences of pain.
There are 2 stories which demonstrate this: the first is a young girl, in early labour, practically hysterical with pain. It turned out she had seen her mother die in childbirth in Bangladesh, and the fear this engendered heightened her pain massively; in the next bed to her, another Bangladeshi woman made no outward sign of being in labour at all, to the extent that the baby’s head was crowning before the midwife was aware that labour was established.
The other story comes from Lorimer Moseley, an Australian physiotherapist who is an expert in chronic pain. He relates how he was camping in the bush in Australia, and was bitten by a snake. At the time, he didn’t realize, and the bite was almost painless, but the ensuing damage and pain was tremendous as the venom took effect. Some months later, fully recovered, he was in a park in Sydney, where a branch happened to brush lightly against the area where he had been bitten: causing him excruciating pain, completely disproportionate to the stimulus.
“The pain has receded but what’s left is the shell of the pain, an empty space where there should be pain but instead there is the expectation of pain.” (Audrey Niffenegger The Time Traveler’s Wife p.476)
What about the treatability of pain?
The reality is that chronic pain does not respond well to treatment. In Sweden, where there is much greater accessibility to pain services than in the UK (for example), one might expect patients to be much more satisfied with the results, but in fact, the problems in that country are even greater than elsewhere, perhaps because, as an expert who works there points out:
“Pain that is unavoidable is bearable, but pain which is avoidable becomes unbearable” Prof Joanne Dahl
In my experience with patients with chronic pain, regardless of cause, once they accept that it is not going to go away, they take an enormous step towards finding it easier to cope with. Of course, this acceptance is really difficult, especially when pain doctors keep suggesting new avenues of treatment...it is human nature to want to change that which is changeable.
Persistence of pain
Why isn’t treatment of chronic pain effective? Pain clinics (if being candid) will admit they tend to achieve less than 50�uccess rate: hardly a good result. This is not simply because of limited drugs, as we have a widening armamentarium: research into treatment has looked into some pretty weird sources of chemicals, such as from tree frogs or venomous snails. Ongoing research funds to find effective pain relief run into billions of dollars.
There are two main reasons why pain treatment tends not to work well over time. Firstly, pain is complex, so targeting a single chemical transmitter is not likely to work. Secondly, as a survival mechanism, pain is a priority signal that demands attention. Think of it like a naughty toddler, insisting on being noticed. Some years ago, my family were travelling in the car across Dartmoor, a wild and bleak area in Southwest England. Our three young children were getting as bored of looking at the horizontal rain, and the occasional sheep amongst the grey rocks as the adults were. My son piped up, “Mum, I want an apple!” “Sorry, we don’t have any” I replied. “But I want an apple!” “Why can’t I have an apple?” I explained that we hadn’t brought any food with us. “Why can’t you buy one?” I looked out over the empty moor; “Do you see any shops out there?” I asked. He shook his head, but was getting more and more fed up. The argument continued for several minutes, at which point, parental authority was exerted and silence fell. Some minutes later, a small voice piped up from the back of the car, “Well, can I have a banana then?”
Chronic pain is like that: irrational, but very persistent.
In this brief talk, I can only give the most cursory of introductions into this enormously complex subject.
When I talk to groups of patients with chronic pain, I always end with the following joke to demonstrate the point that although pain is incredibly complex and we can use a lot of jargon, the basic facts are simple: pain is a survival mechanism, has only indirect relationship to tissue damage and although chronic pain serves no useful purpose, we are programmed to carry on receiving the signal whether we want to or not.
Sherlock Holmes and Dr Watson went on a camping trip. After a good meal and a bottle of wine they lay down for the night, and went to sleep.
Some hours later, Holmes awoke and nudged his faithful friend.
"Watson, look up at the sky and tell me what you see."
Watson replied, "I see millions and millions of stars."
"What does that tell you?" Watson pondered for a minute.
"Astronomically, it tells me that there are millions of galaxies and potentially billions of planets.
Astrologically, I observe that Saturn is in Leo.
Horologically, I deduce that the time is approximately a quarter past three.
Theologically, I can see that God is all powerful and that we are small and insignificant.
Meteorologically, I suspect that we will have a beautiful day tomorrow.
What does it tell you? “
Holmes was silent for a minute then spoke. “It’s elementary my dear Watson.
Someone has stolen our tent."
Dr Sarah Fox