Chronic fatigue syndrome. Recent advances in diagnosis and treatment.

Chronic fatigue syndrome is a chronic debilitating illness that is marked in the majority of cases by sudden onset of fatigue and flulike symptoms. Symptoms subsequently relapse and remit and may persist for years. Physical examination typically reveals relatively minor, nonspecific abnormalities in an apparently well patient. Although immunologic abnormalities are associated with chronic fatigue syndrome, tests for these features are expensive, nonspecific, and generally reserved for research purposes. The diagnosis is made on the basis of new onset of severe fatigue, a characteristic pattern of symptoms, and exclusion of other illnesses. Treatment is aimed at alleviating symptoms and helping patients adjust to the debilitating and chronic nature of the illness.