The spectrum of diseases causing fever of unknown origin in Turkey: a multicenter study

SummaryObjectiveThe purpose of this trial was to determine the spectrum of diseases with fever of unknown origin (FUO) in Turkey.MethodsA prospective multicenter study of 154 patients with FUO in twelve Turkish tertiary-care hospitals was conducted.ResultsThe mean age of the patients was 42 ± 17 years (range 17–75). Fifty-three (34.4%) had infectious diseases (ID), 47 (30.5%) had non-infectious inflammatory diseases (NIID), 22 (14.3%) had malignant diseases (MD), and eight (5.2%) had miscellaneous diseases (Mi). In 24 (15.6%) of the cases, the reason for high fever could not be determined despite intensive efforts. The most common ID etiologies were tuberculosis (13.6%) and cytomegalovirus (CMV) infection (3.2%). Adult Still's disease was the most common NIID (13.6%) and hematological malignancy was the most common MD (7.8%). In patients with NIID, the mean duration of reaching a definite diagnosis (37 ± 23 days) was significantly longer compared to the patients with ID (25 ± 12 days) (p = 0.007). In patients with MD, the mean duration of fever (51 ± 35 days) was longer compared to patients with ID (37 ± 38 days) (p = 0.052).ConclusionsAlthough infection remains the most common cause of FUO, with the highest percentage for tuberculosis, non-infectious etiologies seem to have increased when compared with previous studies.