The term fibrositis has been commonly used but seems inappropriate in view of the lack of histologic evidence of inflammation. Alternatively, the generalized syndrome has been called fibromyalgia, and the localized forms have been called myofascial pain syndromes. These syndromes are defined by pain and tenderness of muscle groups that cannot be attributed to other causes. Studies of the tender areas have revealed no consistent histopathologic findings, and results of routine blood tests and imaging studies are normal. The clinical characteristics of fibromyalgia are distinct from those of other rheumatic disorders.
Patients complain of severe continuing pain, usually with stiffness.
Fibromyalgia most frequently involves the axial skeleton, shoulders, and hips but may also involve the distal extremities. The pain is characteristically severe, although it varies in intensity. Most patients complain of fatigue, which may be overwhelming and is often the chief complaint. Nearly all patients report nonrefreshing sleep. Detailed electroencephalographic studies have documented the disturbance of the normal delta wave pattern of stage 4 sleep by the intervention of alpha waves, referred to as alpha-delta sleep.