Case Report: Mycobacterium avium Complex Infection as a Cause of Fever of Unknown Origin in HIV Disease

Abstract

Fever of unknown origin (FUO) is a common presenting complaint in patients with HIV disease. This article presents a case where Mycobacterium avium Complex (MAC) infection is identified as the cause of FUO in a patient with late stage HIV disease, and reviews the diagnostic and therapeutic strategy for effective management of this condition. MAC is an atypical mycobacterium which causes disseminated disease in up to 50% of HIV patients at some point during their illness. Studies have found it to be responsible for FUO in up to 21% of cases where a cause of fever could be identified. Blood cultures are a sensitive method of detecting MAC infection, and a single positive blood culture is diagnostic for disseminated MAC disease. Current laboratory techniques allow identification of MAC in the blood within 7 to 14 days of collection. The most effective treatment protocol for dissemi-nated MAC disease involves a three drug regimen of rifabutin, ethambutol and clarithromycin, that leads to rapid clearance of the organism from the blood and significant reduction in the severity of symptoms. Primary prophylaxis with clarithromycin has also been shown to reduce the incidence of MAC infection in HIV patients. Given that MAC has been found to have a significant impact on the mortality of HIV patients, it is important to maintain high diagnostic suspicion when evaluating patients with FUO so that treatment may begin promptly to improve patients’ quality of life and prolong survival.