[Fibromyalgia. A critical review]

Fibromyalgia is a chronic pain syndrome, more common in women. Its prevalence is estimated around 2% in the general population, and up to 20% among rheumatology outpatients. Besides musculoskeletal pain, symptoms as fatigue and sleep disturbance are considered characteristic. Research criteria have been set up, but their seemingly preciseness is unable to distinguish clearly between fibromyalgia and other functional somatic syndromes (chronic fatigue syndrome, irritable bowel syndrome) and psychiatric disorders (depression, anxiety), with which a striking comorbidity is documented. The diagnosis of fibromyalgia does not theoretically require the exclusion of muscle, joint, or metabolic diseases, but in clinical practice this problem proves to be of crucial importance. There are numbers of pathophysiological hypothesis for fibromyalgia, but none of them is fully satisfying: muscle is probably innocent; sleep disturbance, although sometimes considered a landmark of the syndrome, is unspecific; stress response studies show subtle anomaly; psychiatric disorders may represent factors of vulnerability and perpetuation rather than causes. We propose to include some of these etiological contributors in vicious circles leading to a "final common pathway" characterized by generalized hyperalgesia. Treatments of fibromyalgia, whether pharmacological (antidepressants) or psychological (cognitive-behavioral therapies) are of little efficacy, and the global prognosis of fibromyalgia is poor. However, the outcome might prove better outside the specialized clinics in which studies of chronic sufferers with severe abnormal illness behaviors are done. The social consequences of the popularization of the diagnosis of fibromyalgia should not be neglected.