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Fever of Unknown Origin (FUO)

Scott T. Henderson, MD Reviewed 06/2019
 


BASICS

DESCRIPTION

  • Classic definition

    • Repeated fever >38.3°C

    • Fever duration at least 3 weeks

    • Diagnosis remains uncertain after 1 week of study in the hospital.

  • The definition of fever of unknown origin ...

DIAGNOSIS

HISTORY

  • Onset and pattern of fever

  • Constitutional symptoms:

    • Chills, night sweats, myalgias, weight loss with an intact appetite (infectious etiology)

    • Arthralgias, myalgias, fatigue (inflammatory...

TREATMENT

GENERAL MEASURES

  • Treatment depends on the specific etiology.

  • Therapeutic trials are a last resort and should be as specific as possible based on available clinical evidence. Avoid “shotgun” ap...

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Patient Monitoring

If the etiology of the fever remains unknown, repeat the history, physical exam, and screening lab studies. 

DIET

No specific dietary recommendati...

REFERENCES

1
Mourad O, Palda V, Detsky AS. A comprehensive evidence-based approach to fever of unknown origin. Arch Intern Med.  2003;163(5):545–551. [View Abstract on OvidMedline]
2
Takeuchi M, Dah...

ADDITIONAL READING

  • Cunha BA, Lortholary O, Cunha CB. Fever of unknown origin: a clinical approach. Am J Med.  2015;128(10):1138.e1–1138.e15. [View Abstract on OvidMedline]

  • Hayakawa K, Ramasamy B, ...

CODES

ICD10

R50.9 Fever, unspecified 

ICD9

780.60 Fever, unspecified 

SNOMED

7520000 Pyrexia of unknown origin (finding) 

CLINICAL PEARLS

  • A sequential approach to FUO based on a careful history, physical examination, with targeted testing and imaging typically yields an appropriate diagnosis and avoids excessive nontarge...

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