Today in Morning Report, we discussed the workup of a Fever of Unknown Origin (FUO).
To review, FUO is defined as a temperature higher than 38.3°C on several occasions and lasting longer than 3 weeks, with a diagnosis that remains uncertain after 1 week of investigation, that commonly include:
- a full history and physical
- CBC, electrolytes, creatinine, glucose, liver enzymes, LDH, bilirubin
- blood cultures and blood film
- hepatitis serology (if liver enzymes abnormal)
- urinalysis, urine microscopy, and urine culture
- CXR
The three broad categories in which to frame one's differential diagnosis of FUO commonly include:
- infections
- malignancies
- connective tissue diseases
A systematic review published right here in Toronto in the Archives of Internal Medicine in 2003 detailing a Comprehensive Evidence-Based Approach to Fever of Unknown Origin recommend the following workup for FUO (in addition to the above):
- ANA, RF
- HIV, CMV, EBV, Q-fever
The following diagram outlines a suggested evidence-based approach for the further workup of FUO after the above investigations are complete:
The aim is to find the cause, in order to temper the Disco Inferno.
