Classical Fever of Unknown Origin: Retrospective Study in Infectious Clinical Hospital №2

BACKGROUND: Despite the recent advances in medicine, fever of unknown origin (FUO) remains a diagnostic and therapeutic challenge even to expert physicians. The etiological structure of FUO is determined by many factors, including the one where a person lived and where has been hospitalized. The aim of this study is to investigate the etiology and clinical characteristics of adult classical FUO with more diagnostics available and to analyze the factors for certain disease categories. METHODS: The clinical data were retrospectively analyzed from 80 patients with cFUO hospitalized at the Infectious Clinical Hospital №2 between October 2015 and October 2016 the patients who met the D.Durack criteria (1) An axillary temperature of >38.0 which corresponds oral temperature of >38.3; (2) illness duration is more than 3 weeks; (3) there is no definite diagnosis after three outpatient visits or 3 days in the hospital with intensive investigations; (4) the fever is not related to FUO of other groups: nosocomial FUO, FUO in patients with AIDS, neutropenia were included. RESULTS: Of the 80 FUO cases, 70 were positively diagnosed with a diagnosis rate of 87,5%. Infectious diseases were still the primary causes of FUO 63% (n = 50). Among them the most frequent diagnoses were bacterial infection of unspecified site 12.5% (n = 10), infective endocarditis 11% (n = 9), as well as pneumonia 7.5% (n = 6) and viral infections of unspecified site 7.5% (n=6). Connective tissue diseases and other noninfectious inflammatory diseases accounted for 17.5% of the FUO cases among which SLE and autoimmune thyroiditis were the most common etiologies and made up 5% (n = 4) and 3,75% (n = 3), respectively. Neoplasms were 8% (n = 6) in our sample. Also ten patients (12,5%) could not be confirmed until they were discharged from hospital. CONCLUSION: Infectious diseases are the major causes of FUO, and the most common cause is bacterial infection of unspecified site. To determine the etiology was difficult due to the limited conditions of the clinical hospital. Infectious endocarditis was found on the second place. The most common causative agents of infective endocarditis were MRSA (3/9) и streptococcus viridans (4/9). The frequency of undiagnosed cases was increasing, but in most FUO cases the causes can be diagnosed eventually after careful analysis of clinical data. DISCLOSURES: All authors: No reported disclosures.