Fever of unknown origin: a report of 57 cases.

Fever of unknown origin (FUO) is defined as the body temperature higher than 38.3 degrees C on several occasions and lasting longer than 3 weeks, with the aetiology remaining uncertain after 1 week of investigation. In this study, we reviewed 57 patients with FUO hospitalised in our inpatient department between 1998 and 2003. The median age of the patients was 44 years (17-84), and 26 were males (46%), while 31 were females (54%). In 24 patients (42%), infectious diseases such as tuberculosis (12 patients) and brucellosis (5 patients) were found under the aetiology of FUO. Inflammatory rheumatic diseases were the second most common cause of FUO (17 patients, 30%), while malignancies were found in 10 patients (18%). In six patients (10%), aetiology could not be identified. In conclusion, infectious diseases especially tuberculosis and brucellosis are the leading causes of FUO in our country.