Fiebre De Origen Desconocido

REVIEW ARTICLE

A Comprehensive Evidence-Based Approach to Fever of Unknown Origin
Ophyr Mourad, MD, FRCPC; Valerie Palda, MD, MSc; Allan S. Detsky, MD, PhD

Background: Fever of unknown origin (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. Methods: A systematicreview was performed to de-

velop evidence-based recommendations for the diagnostic workup of FUO. MEDLINE database was searched (January 1966 to December 2000) to identify articles related to FUO. Articles were included if the patient population met the criteria for FUO and they addressed the natural history, prognosis, or spectrum of disease or evaluated a diagnostic test in FUO. The qualityof retrieved articles was rated as “good,” “fair,” or “poor,” and sensitivity, specificity, and diagnostic yield of tests were calculated. Recommendations were made in accordance with the strength of evidence.
Results: The prevalence of FUO in hospitalized patients

arteritis in the elderly (16%-17%) were important considerations. Four good natural history studies indicate that most patientswith undiagnosed FUO recover spontaneously (51%-100%). One fair-quality study suggested a high specificity (99%) for the diagnosis of endocarditis in FUO by applying the Duke criteria. One fair-quality study showed that computed tomographic scanning of the abdomen had a diagnostic yield of 19%. Ten studies of nuclear imaging revealed that technetium was the most promising isotope, showing a highspecificity (94%), albeit low sensitivity (40%-75%) (2 fair-quality studies). Two fairquality studies showed liver biopsy to have a high diagnostic yield (14%-17%), but with risk of harm (0.009%0.12% death). Empiric bone marrow cultures showed a low diagnostic yield of 0% to 2% (2 fair-quality articles).
Conclusions: Diagnosis of FUO may be assisted by the Duke criteria for endocarditis, computedtomographic scan of the abdomen, nuclear scanning with a technetiumbased isotope, and liver biopsy (fair to good evidence). Routine bone marrow cultures are not recommended.

is reported to be 2.9%. Eleven studies indicate that the spectrum of disease includes “no diagnosis” (19%), infections (28%), inflammatory diseases (21%), and malignancies (17%). Deep vein thrombosis (3%) and temporal

ArchIntern Med. 2003;163:545-551 Fever of unknown origin is frustrating for patients and physicians because the diagnostic workup often involves numerous noninvasive and invasive procedures that sometimes fail to explain the fever. There are well over 200 different reported causes of FUO.3,4 To date, there are no published guidelines or evidence-based recommendations for the diagnostic workup of FUO.The body of literature that discusses FUO comprises case series and cohort studies. In FUO, there is no diagnostic gold standard against which other diagnostic tests may be measured. Final diagnoses are determined in a number of ways, including natural history, biopsy, surgery, postmortem examinations as well as other imaging techniques. For these reasons, there is disagreement as to what shouldconstitute a comprehensive diagnostic workup. To have a structured, sensible, and effective approach, the clinician must have

From the Departments of Medicine (Drs Mourad, Palda, and Detsky) and Health Policy Management and Evaluation (Drs Palda and Detsky), University of Toronto; and the Division of General Internal Medicine, St Michael’s Hospital (Drs Mourad and Palda) and Mt Sinai Hospitaland University Health Network (Dr Detsky), Toronto, Ontario.

EVER OF unknown origin (FUO) identifies a syndrome of fever that does not resolve spontaneously, in which the cause remains elusive after an extensive diagnostic workup. Petersdorf and Beeson1 first coined the term fever of unknown origin in 1961 and explicitly defined it as a temperature higher than 38.3°C on several occasions and...