Our understanding of pain has transformed largely because we can now look into the brain and observe what is going on there when the body appears to hurt. Neuroscience (including advanced imaging where we can see nerve and brain activity in real time) has opened a window where none existed before. We can actually see the behaviour or activitiy of the brain when a person is thinking, emoting, in chronic pain, acute pain, moving, imagining, crying, etc. In the past we saw outward human behaviour but couldn't see brain activity so our ideas and theories were based on an understanding that the brain was static and hard wired; kind of an innert computer like machine. Coupled with that is the fact that the various health professions and their specialties tend to view human function from different perspectives. Furthermore some problems result in various signs and symptoms of apparently somatic (or in body) aches and pains but defy a single diagnosis.
Fibromyalgia is one such condition which is often diagnosed when an individual has chronic diffuse musculoskeletal pain. That patient is also likely to see a gut specialist for gut sensitivity, a Neurologist for head and face pain, their psychologist for cognitive symptoms such as 'feeling muzzy or foggy' and the GP for any of the above. And of course they may see a chiropractor or physiotherapist for 'aches and pains' While it's certainly possible for any one individual to be suffering from multiple maladies it is most likely that there is a systemic or widespread cause which manifests in a variety of ways. Confusing?
Eric Kandel (who won a Nobel for neural science) describes pain as an emotional reaction to sensation and also as a complex behaviour. This is quite different from the old idea that a brain is like a computer hence the title of a recent book 'The brain that changes itself'. If we want to race that marathon we train. Why? When we stress our bodies they can adapt and become stronger however if we do too much too soon we can overdo it, break down and accumulate injuries. Because we all have a unique set of genes we are all slightly more and less predisposed to certain problems. It turns out that the brain can do the same thing. It can respond to stress by developing better coping mechanisms or respond to too much stress by becoming dysfunctional.
Fibromyalgia is characterized by combinations of diffuse musculoskeletal pain often including head ache and TMJ or jaw pain, gut sensitivity, cognitive difficulties (feeling dull or fuzzy in the head) and psychological or emotional lability. So what used to happen to people in the past when we understood pain to be purely due to serious pathology (say infection or blood disorder) injury or scarring OR a psychosomatic issue (all in your head)?
Tests often come back negative. This is good when we're trying to pin point a diagnosis. Then we read the scientific literature which says a few things about FM
1. There appears to be a familial (genetic) predisposition. A first level relative is 8 times more likely to develop similar symptoms.
2. Symptoms seem triggered by the environment (often a combination of severe or sustained emotional stress coupled with musculoskeletal injury (more often injury to the axial skeleton (spine and pelvis) and trunk)
3. Dysfunction in the HPA (hypothalamopituitary axis) and ANS (autonomic nervous system)
4. Impaired pain and sensory processing
5. Cognitive, behavioural and psychological impairments.
In effect the brain becomes 'globally' sensitive so any structure of the body can begin to hurt even though there may be little, even no actual structural injury. Depressingly much of the freely available information regarding FM will say that there is no cure. It's important to understand the nature of FM - It is not a disease with a cure rather a genetically linked predisposition to brain sensitivity. Furthermore because we now understand the brain to be plastic or changeable it is theoretically possible to reverse some of these changes. So FM can be complex and difficult to manage and although it does respond slowly and less predictably than other simple joint and muscle problems it can respond well over time.
Source: Principles of Neural Science, Fifth Edition, Eric R. Kandel, 2007