Fever of unknown origin (FUO) on a land on cross-roads between Asia and
Europa; a multicenter study from Turkey
Abstract
Aims: The differential diagnosis of Fever of Unknown Origin (FUO) is
still a major clinical challenge despite the advances in diagnostic
procedures. In this multicenter study, we aimed to reveal FUO etiology
and factors influencing the final diagnosis of FUO in Turkey. Methods: A
total of 214 patients with FUO between the years 2015-2019 from 13
tertiary training and research hospitals were retrospectively evaluated.
Results: The etiologic distribution of FUO was infections (44.9%),
malignancies (15.42%), autoimmune/inflammatory (11.68%) diseases,
miscellaneous diseases (8.41%) and undiagnosed cases (19.62%).
Brucellosis (10.25%), extrapulmonary tuberculosis (6.54%) and
infective endocarditis (6.54%) were the most frequent three infective
causes. Solid malignancies (7.1%) and lymphoma (5.6%), adult-onset
still’s disease (6.07%) and thyroiditis (5.14%) were other frequent
diseases. The etiologic spectrum did not differ in elderly
(p<0.05). Infections were less frequent in Western (34.62%)
compared to Eastern regions of Turkey (60.71%) (p< 0.001, OR:
0.31, 95% Cl: 0.19 to 0.60). The ratio of undiagnosed etiology was
significantly higher in elderly (p: 0.046, OR: 2.34, 95% Cl: 1.00 to
5.48) and significantly lower in Western Turkey (p: 0.004, OR: 3.07,
95% Cl: 1.39 to 6.71). Conclusion: Brucellosis, extrapulmonary
tuberculosis and infective endocarditis remain to be the most frequent
infective causes of FUO in Turkey. Solid tumors and lymphomas, AOSD and
thyroiditis are the other common diseases. The etiologic spectrum did
not differ in elderly, on the other hand, infections were more common in
Eastern Turkey. A considerable amount of etiology remained undiagnosed
despite the state-of-the-art technology in healthcare services.