Fibromyalgia syndrome: Presentation, diagnosis, and differential diagnosis

Fibromyalgia syndrome (FMS) typically presents with widespread soft tissue pain. A research classification of this disorder, used since 1990 to make the diagnosis, depends on the history of wide-spread pain and prominent tenderness to palpation at ≥11 of 18 anatomically-defined tender points throughout the body. Therefore, FMS is a criteria-based diagnosis rather than a diagnosis of exclusion. Common comorbid manifestations of FMS can include severe insomnia, body stiffness, affective symptoms, irritable bowel syndrome, and urethral syndrome. Epidemiologically, FMS can occur at any age, but is more common in adult females than in adult males. FMS can accompany a number of other conditions such as rheumatic diseases, infections, and endocrine disorders, so differential diagnosis is important even after making a diagnosis of FMS.