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Case Reports

Abstract

An 83-year-old man presented to the emergency department with delirium, rapid cognitive decline, and an ulcerating chronic wound on the left buttock, initially acquired after a fall at a local park four years prior. Multiple brain imaging studies showed multifocal edema with meningeal thickening, suggestive of an infectious/inflammatory etiology. On physical exam, a large, erythematous, ulcerative lesion exposing soft tissue was present on the left buttock. Biopsy of this lesion demonstrated extensive granulomatous inflammation within the dermis and subcutis. Trophozoite and cyst forms were identified upon examination of multiple levels, concerning for an amebic infection. The patient quickly decompensated and passed away within one month from admission. Autopsy limited to brain demonstrated amebic encephalitis within lesional tissue. Case specimens sent to the Center for Disease Control confirmed Balamuthia mandrillaris as the causative pathogen. As a free-living, opportunistic ameba, B. mandrillaris has only caused human disease in 200+ cases around the world. Half of these cases are from the United States, with increased prevalence in southwestern states. Herein, we present the first confirmed case of B. mandrillaris in Canada. Due to the difficulty of identifying these amebic forms on routine histology and microbial special stains, cutaneous infections can remain undiagnosed for months until progression to central nervous system involvement, at which point the infection carries a near 100% fatality rate. Having a high index of suspicion upon identifying prominent granulomatous inflammation appears to be a salient and crucial first step in the diagnosis of amebic infections in the skin.