Korean J Med.  2021 Apr;96(2):101-109. 10.3904/kjm.2021.96.2.101.

Fever of Unknown Origin: An Overview of the Diagnostic Approach

• Kim EJ

• KMID: 2514549
• DOI: http://doi.org/10.3904/kjm.2021.96.2.101

Abstract

Although fever of unknown origin (FUO) was first defined in 1961, it remains a diagnostic challenge. The revised 1991 definition categorized FUO into classic FUO, nosocomial FUO, neutropenic FUO, and human immunodeficiency virus-related FUO, each requiring at least three outpatient visits or 3 days of in-hospital stay. The causes of classic FUO differ greatly geographically and temporally, and are divided into infections, noninfectious inflammatory diseases, neoplasms, and miscellaneous diseases. A systematic, comprehensive and rational approach is required for appropriate diagnosis. A medical history and physical examination are very important; they may reveal diagnostic clues. Here, we review the literature on the causes and diagnostic approaches of classical FUO.

Keyword

Fever of unknown origin; Diagnosis; ¹⁸ FDG-PET/CT