Diagnostic workup for fever of unknown origin: a multicenter collaborative retrospective study

Area of Science:

• Internal Medicine
• Infectious Diseases
• Rheumatology

Background:

• Fever of unknown origin (FUO) diagnosis is challenging due to diverse etiologies that vary geographically and temporally.
• Previous research on FUO in Japan has been limited to single institutions or regions, lacking a comprehensive nationwide perspective.

Purpose of the Study:

• To conduct a nationwide study identifying the spectrum of diseases causing FUO in Japan.
• To determine useful diagnostic tests and considerations for patients presenting with FUO.

Main Methods:

• A nationwide retrospective study was conducted across 17 hospitals affiliated with the Japanese Society of Hospital General Medicine.
• Included were 121 adult patients diagnosed with classical FUO between January and December 2011, defined by specific temperature and duration criteria.

Main Results:

• Non-infectious inflammatory diseases (30.6%) and infectious diseases (23.1%) were the most frequent causes of FUO.
• Malignancy accounted for 10.7% of cases, with 23.1% remaining undiagnosed.
• Diagnostic tests included blood cultures (86.8%), serum procalcitonin (43.8%), and positron emission tomography (29.8%).

Conclusions:

• The prevalence of FUO due to deep-seated abscesses or solid tumors appears to be decreasing with advanced imaging techniques.
• Polymyalgia rheumatica emerged as a frequent cause in an aging population, and HIV/AIDS was noted as an important consideration for FUO in Japan.
• The study identified key differential diagnoses for FUO, emphasizing the need for tailored diagnostic strategies.