Fever of unknown origin: analysis of 71 consecutive cases.

Background: Fever of unknown origin (FUO) is still an important problem in clinical practice. Evaluation of patient characteristics may clarify the utility of diagnostic tests and etiologies of FUO.

Methods: Fever of unknown origin in 71 patients was investigated at Ankara Numune Education and Research Hospital in Turkey between February 2001 and December 2004.

Results: Mean hospital stay and fever duration was 20.5 days and 44 days, respectively. Etiologies of FUO were as follows: infections 32 (45.1%), collagen vascular disease 19 (26.8%), neoplasm 10 (14.1%), and miscellaneous diseases 4 (5.6%). Diagnosis remained obscure in 6 patients (8.5 %). Tuberculosis was found to be 40% of the infectious causes of FUO. Mean hospital stay and fever duration were prolonged in infectious cases. Female predominance was observed in collagen vascular diseases (P = 0.047). Splenomegaly and lymphadenopathy were common in the neoplasm group (P = 0.017, P = 0.017, respectively). Erythrocyte sedimentation rate, aspartate aminotransferase, alanine aminotransferase and lactate hydrogenase levels were elevated in patients with collagen vascular diseases. Nine (12.7%) patients died during the follow-up period.

Conclusions: Hospital stay and fever duration were prolonged in the infectious group of FUO patients. Infectious diseases, particularly tuberculosis, were the most important cause of FUO in our series. Tuberculosis should be kept in mind as an important etiology of FUO countries where tuberculosis is endemic.