Evaluating fever of unknown origin definitions in a tertiary care setting: Implications for diagnostic criteria revision

• DOI: 10.5493/wjem.v15.i2.101388
• Publication Date: 2025-04-11T07:35:38Z
• Authors: Pathik Dhangar; Prasan Kumar Panda; Ravi Kant; Rohit Gupta; Ruchi Dua; Ashutosh Tiwari; Sandeep Saini; Kavita Khoiwal; Yogesh Bahurupi
• Keywords: Tertiary care

BACKGROUND Fever of unknown origin (FUO) remains a diagnostic challenge and was originally defined in 1961. Its classic criteria include fever ≥ 38.3°C (≥ 101°F) on multiple occasions, lasting three weeks or longer, diagnosis after one week inpatient evaluation. However, these may not fully encompass the varied clinical presentations seen resource-limited settings such as India. The adaptation FUO definitions to local healthcare contexts is crucial for enhancing accuracy optimizing patient outcomes. AIM To investigate applicability revised tertiary care setting METHODS This longitudinal-exploratory study at All India Institute Medical Sciences Rishikesh (January 2018–December 2022) analyzed 228 adult patients with 99.1 °F over days. Patients diagnosed within days admission were excluded. Data collected retrospectively prospectively using predefined based durations nondiagnosis (3-21 days, > 21 days), temperature ranges (99.1 °F-100.9°F, 101°F), hospitalization (3-7 7 days). Descriptive statistics comparative tests (Fisher's exact test, χ 2 test) evaluated outcomes across definitions. RESULTS Among proposed definitions, Definition B (fever 3-21 temperatures between days) predominated (40.8%), while only 2.2% met classical criteria. Notably, 36.5% remained undiagnosed 7-10 despite 94% undergoing workups Infection emerged leading etiology without significant variation mortality during (χ = 27.937, P 0.142). CONCLUSION Adapting improves treatment. (40.8% prevalence) showed practical utility, higher discharged empirical 'Anti-tuberculosis therapy'.