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[Various causes of fever of unknown origin]

A-C De laco1, G Praz

  • 1Département de médecine interne CHCVs, Hôpital de Sion, Sion. annecatherine@deiaco.com

Revue Medicale Suisse
|November 18, 2008
PubMed

Insights

Fever of unknown origin (FUO) presents as prolonged fever without a clear diagnosis after extensive testing. While many cases remain undiagnosed, the prognosis is generally favorable, emphasizing clinical evaluation over algorithmic testing.

Area of Science:

  • Internal Medicine
  • Infectious Diseases
  • Rheumatology

Context:

  • Fever of unknown origin (FUO) is a clinical challenge defined by persistent fever exceeding three weeks without an etiological diagnosis despite thorough investigation.
  • FUO encompasses diverse causes including infections (e.g., endocarditis, tuberculosis), inflammatory conditions (e.g., temporal arteritis, Still's disease), neoplastic disorders, and miscellaneous factors.

Purpose:

  • To summarize the definition, classification, diagnostic approach, and prognosis of fever of unknown origin.
  • To highlight the importance of detailed patient history and physical examination in guiding diagnostic workup for FUO.

Summary:

  • FUO is characterized by prolonged fever without diagnosis, categorized into infectious, inflammatory, neoplastic, and miscellaneous subgroups.
  • A significant proportion (about one-third) of FUO cases remain undiagnosed after comprehensive evaluation, yet typically carry a good prognosis.
  • Diagnostic strategies for FUO should prioritize focused clinical assessment over rigid algorithmic testing, reserving empirical treatment for critical situations.

Impact:

  • Informs clinicians on the multifaceted nature of FUO and the diagnostic yield of clinical assessment.
  • Provides a framework for understanding the prognosis of FUO, reassuring clinicians and patients about outcomes in undiagnosed cases.
  • Guides evidence-based clinical practice for managing FUO, emphasizing personalized diagnostic pathways and judicious use of empirical therapies.

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