Adrenal insufficiency: an uncommon cause of fatigue.

BACKGROUND Adrenal insufficiency is a rare condition that can cause common and nonspecific symptoms. One such symptom, reported by all patients with adrenal insufficiency, is fatigue. On the other hand, up to 20% of patients seeking care from primary care physicians will have fatigue as a complaint. Only a small percentage of patients are found to have underlying medical disease. METHODS A MEDLINE literature search was performed from 1966 to the present using the key words "fatigue," "adrenal insufficiency," and "polyglandular autoimmune endocrinopathy." Major endocrinology textbooks were also referenced. In addition, references were obtained from bibliographies of available articles. RESULTS AND CONCLUSIONS This article describes a patient with adrenal insufficiency and fatigue as the primary complaint. A brief discussion of fatigue and clues to organic causes follows, along with a more detailed discussion of adrenal insufficiency. Important medical history or signs and symptoms of organic disease suggest the need for screening tests and more detailed evaluation to uncover the uncommon medical causes of fatigue.