Fever of unknown origin: report of 107 cases in a university hospital.

Fever of unknown origin (FUO) is a challenging problem in clinical practice. Evaluation of patient's characteristics may illustrate the etiologies of FUO. In present study, 107 patients with FUO hospitalized in our inpatient department between 2010 and 2011 were investigated. The median age of the patients was 48 years (15-94). The median fever duration was 8.5 weeks (3-104). The median hospital stay was 8.5 days (1-51). Etiologies of FUO were identified as follows: infectious diseases 32 (29.9%), malignancies 19 (17.8%), inflammatory rheumatic diseases 18 (16.8%), and miscellaneous diseases 15 (14.0%). In 23 (21.5%) patients, the diagnosis remained unclear. Infection group had relative shorter average fever duration and hospital stay than other groups. Shortened mean fever duration was observed in geriatric age group. In conclusion, as the most common cause of FUO in the present study, infectious cases had relative shorter average fever duration and hospital stay, and geriatric patients had shortened average fever duration as well.