Recurrent FUO due to intermittent Enterobacter cloacae bacteremias from an infected pacemaker lead diagnosed by gallium scan

Abstract

Fever of unknown origin (FUO) refers to fevers of ≥101° F that persist for ≥3 weeks and remain undiagnosed after a focused inpatient or outpatient workup. FUO may be due to infectious, malignant/neoplastic, rheumatic/inflammatory, or miscellaneous disorders. Recurrent FUOs are due to the same causes of classical FUOs. Recurrent FUOs may have continuous or intermittent fevers and are particularly difficult to diagnose. With intermittent fever, recurrent FUO diagnostic tests are best obtained during fever episodes. With recurrent FUOs, the periodicity of febrile episodes is unpredictable. We present a case of a 70-year-old male who presented with recurrent FUO. Multiple extensive FUO workups failed to determine the source of his fever. During his last two episodes of fever/chills, blood cultures were positive for Enterobacter cloacae. Episodic E. cloacae bacteremias suggested a device-related infection, and the patient had a penile implant and permanent pacemaker (PPM). Following febrile episodes, he was treated with multiple courses of appropriate antibiotics, but subsequently fever/chills recurred. Since a device-associated infection was suspected, indium and PET scans were done, but were negative. The source of his intermittent E. cloacae bacteremias was finally demonstrated by gallium scan showing enhanced uptake on a cardiac lead, but not the penile implant or PPM. Gallium scanning remains useful in workup of FUOs, particularly when false-negative indium or PET scans are suspected. The involved pacemaker lead was explanted, grew E. cloacae and the patient has since remained fever free.