There may not be one simple answer, but the last few years have moved us closer to an answer to this question. Fibromyalgia (FM) is a chronic pain disorder with unknown etiology and unclear pathophysiology. Here are 10 things we do know.
1. There is no evidence that a single event “causes” fibromyalgia. Rather, many physical and/or emotional stressors may trigger or aggravate symptoms. This may include anything from an infection, such as a viral illness or Lyme disease, to emotional, or physical trauma.
2. Fibromyalgia (FM) is considered to be a disorder of pain regulation. Fibromyalgia shares several features with other pain disorders that are considered to be more central rather than peripheral pain conditions, such as: migraine, tension headaches, temporomandibular joint disorder, and irritable bowel syndrome.
3. It is not a muscle disease. During much of the 20th century, fibromyalgia was thought to be a muscle disease however, years of studies have found no evidence for pathologic or biochemical muscle abnormalities.
4. The muscle soreness associated with FM is now believed to be secondary—a result of pain and inactivity rather than being a primary muscle disorder.
5. It’s in the genes. First-degree relatives of patients with FM are 8.5 times more likely to have FM than relatives of patients with rheumatoid arthritis. This suggests a shared hereditary factor that may account for the overlap of chronic pain and mood disorders (depression, anxiety) in families.
6. Pain processing is off in FM. Alterations in pain and sensory processing in the central nervous system are present in FM. What this means is patients with FM perceive noxious stimuli, such as heat, electrical current, or pressure, as being painful at lower levels of physical stimulation than do healthy controls.
7. Disrupted sleep and FM is a big deal. Underlying central nervous system dysfunction is suggested by the sleep and mood disturbances noted in the majority of FM patients. What is really interesting is that disordered sleep patterns precedes the development of fibromyalgia pain and that abnormal sleep and pain predict depressive symptoms.
8. Autonomic nervous system dysfunction. Yes, that’s a mouthful but know this: abnormal function of the autonomic nervous system in those with FM is suggested by the fact that some patients with FM have been found to have orthostatic hypotension (their blood pressure drops when they stand.)
9. It is not an immune system change. There is little evidence to support the concept that FM is an immune mediated disorder.
10. Hot spots. Fibromyalgia patients often have areas of focal tissue abnormalities including myofascial trigger points or osteoarthritis of the joints and spine. In FM patients there are abnormal peripheral pain generators which means those above listed tender areas may initiate or perpetuate chronic pain.