New outcome measures need to be developed. Current evidence does not favor a single infecting agent as the cause. Psychological symptoms are frequent and may be important in the pathogenesis. Minimal investigations are suggested. No single therapy is definitely useful and a multidisciplinary approach is favored.
Most patents improve considerably over a period of years.
The condition is not caused by ongoing tissue damage, is always potentially reversible and like other chronic pain syndromes is influenced by societal and personal factors more than the initial triggering physical and nociceptive factors. The muscular changes indicating a localized disturbance of microcirculation, which can excite and sensitize nociceptors in the muscle, represent promoting or triggering factors and are not specific for fibromyalgia. Non-noxious electrocutaneous stimulation in the upper limbs of patients with these syndromes was used as a psychophysical tool. No difference in the threshold for sensory perception but marked reduction in pain threshold and pain tolerance were found in patients compared with control subjects. Furthermore, the electrocutaneous stimulation was accompanied by spread and persistence of dysesthesia, in painful limbs only.