Presentations

Abstract

Introduction: Fever of unknown origin (FUO) is a difficult conundrum for clinicians. Technically, the definition requires a minimum of three weeks of fever duration despite adequate workup rather than fever without readily apparent cause. Per some meta-analyses, no diagnosis is made in nearly one-quarter of the cases. We present a case of FUO in a patient who underwent an extensive three-week inpatient workup and was ultimately diagnosed with a disease that often does not present classically.

Case Information: A 70-year-old female presented to the emergency room complaining of fevers and fatigue for three days. Upon arrival, she was febrile and tachycardic. Initial laboratory findings demonstrated leukocytosis, lactic acidosis, elevated Erythrocyte Sedimentation Rate of 98 mm/hr, and mild transaminitis. She was initially started on antimicrobial therapy; however, after having persistent fevers, antibiotics were discontinued. Extensive workup, including testing for sexually transmitted diseases, HIV, tick-borne illnesses, Brucella, Q fever, EBV, and malaria, found no infectious cause. Due to the presence of ankle hardware from a previous surgery, a tagged WBC scan was completed, which demonstrated no localizable areas of inflammation. Her only symptoms besides near-daily fevers were diffuse myalgias and fatigue. She repeatedly denied any vision changes, headache, jaw claudication, temporal tenderness, or arthralgias of the hips or shoulders. Lumbar puncture, liver biopsy due to transaminitis, and bone marrow biopsy due to persistent leukocytosis were completed and were all negative. Rheumatology recommended temporal artery biopsy even though she did not exhibit classic symptoms of giant cell arteritis (GCA), as it is in the differential of FUO. Temporal artery biopsy demonstrated transmural arterial inflammation with giant cells. She was diagnosed with GCA and started on high-dose steroids, which led to the resolution of fevers and improvement of symptoms, and was subsequently discharged with close outpatient Rheumatology follow-up.

Discussion/Clinical Findings: GCA, or Temporal Arteritis, is a vasculitis that affects large and middle-sized blood vessels with a predisposition to involve the cranial arteries derived from the carotid artery in individuals older than 50. GCA has been classically described to present with headache, temporal artery tenderness, and acute vision loss. In reality, only 66% of patients have new headaches, 50% have non-specific constitutional symptoms, only 20-30% have visual disturbance that can be transient, only 50% have jaw claudication, and approximately 50% have extracranial musculoskeletal symptoms presenting as polymyalgia rheumatica. Non-classic presentations without temporal tenderness or visual changes may delay diagnosis. The gold standard for diagnosis is temporal artery biopsy.

Conclusion: Empiric antibiotic therapy is not given to patients with FUO unless they are suspected of having a potentially life-threatening infection. Additionally, for patients with FUO, empiric glucocorticoids are not administered unless the patient is severely ill and suspected of having a steroid-responsive illness. GCA may cause 15% of FUO cases in patients over 65 years of age, and it is important to consider GCA in the differential diagnosis of a patient presenting with FUO, even in the absence of classic symptoms. Early treatment of GCA with steroids can prevent potentially irreversible complications from the disease.