infectious diseases
Fever of Unknown Origin (FUO)
Key Points
Classic FUO is body temperature≥38.0°C rectally for > 3 weeks with no identified cause after 3 days of hospital investigation or≥3 outpatient visits. Identified causes can be categorized as infectious, connective tissue, neoplastic, or miscellaneous. Evaluation should be based on synthesis of history and physical examination, with particular consideration of risk factors and likely causes based on individual circumstances. 