Fibromyalgia (FM or FMS) is characterised by chronic widespread pain and allodynia (a heightened and painful response to pressure). Its exact cause is unknown but is believed to involve psychological, genetic, neurobiological and environmental factors. Fibromyalgia symptoms are not restricted to pain, leading to the use of the alternative term fibromyalgia syndrome for the condition. Other symptoms include debilitating fatigue, sleep disturbance, and joint stiffness. Some patients also report difficulty with swallowing, bowel and bladder abnormalities, numbness and tingling, and cognitive dysfunction. Fibromyalgia is frequently comorbid with psychiatric conditions such as depression and anxietyand stress-related disorders such as posttraumatic stress disorder. Not all fibromyalgia patients experience all associated symptoms. Fibromyalgia is estimated to affect 2–4% of the population, with a female to male incidence ratio of approximately 9:1. The term “fibromyalgia” derives from new Latin, fibro-, meaning “fibrous tissues”, Greek myo-, “muscle”, and Greek algos-, “pain”; thus the term literally means “muscle and connective tissue pain”.
There is evidence that environmental factors and certain genes increase the risk of developing fibromyalgia – these same genes are also associated with other functional somatic syndromes and major depressive disorder. The central symptom of fibromyalgia, namely widespread pain appears to result from neuro-chemical imbalances including activation of inflammatory pathways in the brain which results in abnormalities in pain processing. The brains of fibromyalgia patients show functional and structural differences from those of healthy individuals, but it is unclear whether the brain anomalies cause fibromyalgia symptoms or are the product of an unknown underlying common cause. Some research suggests that these brain anomalies may be the result of childhood stress, or prolonged or severe stress. Certain antidepressants such as amitriptyline and duloxetine have been found to be effective treatments as has the anticonvulsant drug pregabalin.Exercise improves fitness and sleep and may reduce pain and fatigue in some people with fibromyalgia.
Fibromyalgia has been recognized as a diagnosable disorder by the US National Institutes of Health and the American College of Rheumatology. Fibromyalgia, a central nervous system disorder, is described as a “central sensitization syndrome” caused by neurobiological abnormalities which act to produce physiological pain and cognitive impairments as well as neuro-psychological symptomatology. Despite this there is controversy as to the cause and nature of fibromyalgia.Rheumatologists, neurologists, and pain specialists tend to view fibromyalgia as a pathology of both biological and neurobiological origin. Psychiatrists often view fibromyalgia as being a type of affective disorder, and specialists in psychosomatic medicine tend to view fibromyalgia as being somatoform disorder. The controversies involve both healthcare specialists as well as patients, who often object to fibromyalgia being described in purely somatic terms.