Fever of unknown origin in the practice of a rheumatologist

Abstract

Fever of unknown origin (FUO) is mostly due to infections, with rheumatic diseases (RD) and oncologic pathology being its fewer common causes. Rheumatologists periodically encounter this problem, which requires a thorough examination. Objective. To study the structure of diagnosed causes of FUO among patients of the Rheumatology Department and present some cases with difficulties in diagnosis with an emphasis on RD. Materials and methods. We observed 85 patients with a diagnosis of FUO referred to the Rheumatology Department (City Clinical Hospital № 11, Minsk). All patients were examined according to existing algorithms for FUO. Results. In the structure of FUO causes, infections accounted for 43 (50.6 %), oncological and hematological pathology with FUO was detected in 14 (16.5 %) of patients. Among patients with RD, FUO was observed at the onset of RA in 6 (24 %) cases, in Still’s disease — 1 (4 %), SLE — 4 (16 %), histone lupus — 2 (8 %), systemic vasculitis — 12 (48 %) (giant cell vasculitis — 3 (12 %), nonspecific aortoarteritis — 1 (4 %), Behcet’s disease — 1 (4 %), ANCA-associated vasculitis — 7 (25 %), in total 25 (29.4 %) cases. Other causes of FUO account for 3 (3.5 %). 5 (5.9 %) cases of periodontitis occurring with FUO are presented, in 2 cases cone beam computed tomography (CBCT) was made after excluding other infections and neoplasms, although dental radiography was negative. Some cases of RD were presented with diagnostic search analysis. Conclusion. In most patients admitted to the Rheumatology Department 50.6 % infections were found to be responsible for FUO. RD accounted for 29.4 %, and tumours and other causes made a smaller proportion. The periodontitis may be a cause of FUO that occurs atypically, not always routinely detected by dental radiography, therefore, CBCT is advisable. CBCT should be included in the algorithms for examining the patients with FUO without a unknown cause.