The pathogenesis of chronic pain and fatigue syndromes, with special reference to fibromyalgia.

Syndromes characterized by chronic pain and fatigue have been described in the medical literature for centuries. Fibromyalgia is the term currently used to describe this symptom complex, and considerable research has been performed in the last decade to delineate the epidemiology, pathophysiology, and genesis of this entity. Although fibromyalgia is defined by its musculoskeletal features, it is clear that there are a large number of non-musculoskeletal symptoms, such that we now understand that there is considerable overlap with allied conditions such as the chronic fatigue syndrome, migraine and tension headaches, irritable bowel syndrome, and affective disorders. This article will review our current state of knowledge regarding fibromyalgia and these allied conditions, and present a unifying hypothesis that describes both the pathophysiology of symptoms and the genesis of these disorders.