Chronic fatigue syndrome

Alternative names:

C.F.I.D.S.; C.F.S.; chronic fatigue and immune dysfunction syndrome; fatigue - chronic; yuppie flu

Definition:

A condition of prolonged and severe tiredness or weariness (fatigue) that is not relieved by rest and is not directly caused by other conditions.

Causes, incidence, and risk factors:

The exact cause of chronic fatigue syndrome (C.F.S.) is unknown. Some researchers suspect it may be caused by a virus, such as human herpes virus-6 (HHV-6); however, no distinct viral cause has been identified.

Recent studies have shown that chronic fatigue syndrome MAY be caused by inflammation of pathways in the nervous system; and that this inflammation MAY be some sort of immune response or autoimmune process. C.F.S. may occur when a viral illness is complicated by an inadequate (dysfunctional) immune response or by other factors (such as age, prior illness, stress, environment, or genetic disposition). C.F.S. most commonly occurs in women between 30 to 50 years of age.

The Centers for Disease Control (CDC) describes C.F.S. as a distinct disorder with specific symptoms and physical signs, based on the exclusion of other possible causes. The number of patients with C.F.S. is unknown.

Symptoms of C.F.S. appear much like symptoms of most common viral infections (muscle aches, headache, and fatigue). The symptoms often develop within a few hours or days and last for 6 months or more.