Fever of Unknown Origin in Older Adults: A Prospective Observational Study from North India.

OBJECTIVES: Fever of unknown origin (FUO) has different etiology in different age groups. We aimed to determine the spectrum of FUO in older patients and to establish the underlying etiology. METHODS: This was a hospital-based prospective observational study conducted between January 2018 to June 2019 at Postgraduate Institute of Medical Education and Research, Chandigarh, India. Fifty-one consecutive patients aged 60 years and above met the qualitative criteria of FUO. RESULTS: The etiological distribution was infections in 21 patients (41.2%), malignancies in 16 (31.4%) and noninfectious inflammatory disorders in 8 (15.7%). Six patients (11.8%) remained undiagnosed. Among infections, 15 patients (29.4%) had tuberculosis, and 10 had an extrapulmonary disease. Twelve out of 16 cases with malignancies had a hematological cause, and eight had lymphoma. ;Regarding decisive methods of diagnosis, 18F-fluorodeoxyglucose positron emission tomography was diagnostic in 17 out of 27 patients (63%) and computed tomography in 21 out of 42 cases (50%). Imaging or endoscopy-guided procedures provided a diagnostic clue in 12 out of 14 patients (85.7%), and bone marrow examination results were useful in 9 out of 19 (47.4%). CONCLUSIONS: Infections and malignancies contributed to about three-fourths of cases, with tuberculosis and lymphoma being the commonest etiologies.