Fibromyalgia: a rheumatologic diagnosis?

Fibromyalgia (FM) is a medically unexplained or functional somatic syndrome (FSS). The two classification criteria are chronic widespread pain (CWP) and the finding of 11/18 tender points (TP). FM overlaps and co-occurs with other FSSs, and auxiliary symptoms that are not included in the criteria may be clues to other FSSs. About ten FSSs include chronic fatigue syndrome, myofascial pain syndromes and irritable bowel syndrome. TP do not reflect demonstrable pathology, and are locations where everyone is generally more tender. In FM they are more tender than normal due to lowered pain threshold. High TP counts are associated with the extent of distress or unspecific somatic symptoms in the absence of chronic pain. TP lack validity and should be excluded. CWP and distress are outside the domain of rheumatology, and abnormal mechanisms in FM relate to the central nervous system, as compared to “peripheral” mechanisms studied in rheumatology. FM should not be considered as a rheumatologic condition but rather as part of a broader spectre of FSSs. Patients with FSSs should be considered and treated together across medical specialities by general physicians in primary health care.