Illustrative CasesA Fever of Unknown Origin Workup in the Emergency Department Reveals an Unusual PathogenHernandez-Trujillo, Hillary S. MD*; Dalberg, Todd DO*; Feder, Henry Jr MD†‡; Smith, Sharon R. MD§Author Information From the *Connecticut Children's Medical Center, Hartford; †Division of Infectious Diseases at Connecticut Children's Medical Center, Hartford; ‡Departments of Family Medicine and Pediatrics at University of Connecticut Health Center, Farmington; and §Department of Emergency Medicine at Connecticut Children's Medical Center, Hartford, CT. Reprints: Hillary S. Hernandez-Trujillo, MD, Connecticut Children's Medical Center, 282 Washington St, Medical Education 4H, Hartford, CT 06106 (e-mail: [email protected]). Pediatric Emergency Care: October 2009 - Volume 25 - Issue 10 - p 684-686 doi: 10.1097/PEC.0b013e3181bec8df Buy SDC Metrics Abstract The cause of a fever of unknown origin (FUO, fever of >21 days without an identified etiology) may be a common illness, an atypical presentation of a common illness, or an unusual illness. A patient with an FUO occasionally presents to the emergency department (ED). The differential diagnosis of an FUO is extensive. A primary goal for the ED physician is to determine if the patient with an FUO has a disorder that needs immediate recognition and treatment. We describe a case of a teenage boy who presented to our ED with 2 weeks of high fever and back pain. We describe this teenage boy with FUO and a surprising diagnosis. © 2009 Lippincott Williams & Wilkins, Inc.