Table 3 Subtypes of fever of unknown origin as defined by Durack and Street (1991) [6]
From: Undifferentiated epithelioid sarcoma presenting as a fever of unknown origin: a case report
FUO subtype | Definition | Major causes |
|---|---|---|
Classical FUO | - Temperature of ≧ 38.3 °C - > 3 weeks’ duration of illness - Failure to reach diagnosis with 1 week of in-patient investigations | Malignancies, infections, inflammatory diseases (non-infectious) |
Hospital acquired FUO | - Temperature of ≧ 38.3 °C - Patient hospitalized ≧ 24 hours, fever not present or incubating on admission - Evaluation for ≧ 3 days | HAIs, postoperative complications, drug-induced |
Immunocompromised or neutropenic FUO | - Temperature of ≧ 38.3 °C - Absolute neutrophil count ≦ 500 per mm3 - Evaluation for ≧ 3 days | Various bacterial, viral, and fungal infections |
HIV-related FUO | - Temperature of ≧ 38.3 °C - Out-patient duration > 4 weeks; > 3 days for in-patients - Confirmed HIV infection | HIV defining infections (Mycobacteria, CMV, Toxoplasma, Cryptococcus), lymphoma, IRIS |