Fever of unknown origin: classic and associated with human immunodeficiency virus infection. a comparative study.

Fever of unknown origin (FUO) associated with HIV infection is different from classic FUO. Relevant etiologies, procedures and time to diagnosis were analyzed. Patients admitted with FUO from 1991 to 1996 were prospectively followed. Thirty with classic FUO (group I) and 46 with FUO and HIV (group II) were included. Data on diagnosis, time to achieve it, and procedures were registered. Diagnosis was obtained in 87% and 93% of cases in groups I and II. Infections were the most frequent cause in group II. Collagen diseases were found in group I and absent in group II. Prevalence of neoplasia was similar. Mean time to diagnosis was near 5 weeks. In HIV the predominant diagnostic method was the Lowenstein culture. Invasive methods were similarly employed. It is concluded that predominance of Mycobacteria and absence of collagen diseases make FUO associated with HIV a different form of FUO. No differences were found in approach and time to diagnosis.