(547) An Ominous Presentation of Histoplasmosis in a COVID-19-Positive Patient

Introduction: Histoplasmosis is an endemic fungal infection most commonly found in temperate areas worldwide. While the majority of cases of histoplasmosis are asymptomatic or mildly symptomatic and self-limited, some patients can develop disseminated histoplasmosis with a wide range of presentations with an approximate frequency of 1 in 2000 cases. Prompt recognition and treatment of histoplasmosis is essential in preventing the development of disseminated disease.

Description: Our patient is a 52-year-old female who presented with hypoxia, found to be COVID-19 positive with her CT showing bilateral upper and lower lobe ground glass opacities. She returned to the hospital twelve days after discharge with encephalopathy, hypoxia, and shock. Repeat CT showed interval worsening of bilateral pulmonary infiltrates. She was intubated and met Berlin criteria for acute respiratory distress syndrome. Cultures, antibody titers, and immunodiffusion were consistent with disseminated histoplasmosis and she was started on amphotericin B. She ultimately expired on hospital day sixteen.

On imaging, COVID-19 is most commonly described as ground-glass opacities and consolidations with a bilateral and peripheral distribution. Comparatively, histoplasmosis has a wide range of radiological manifestations depending on its severity and chronicity. Acute pulmonary histoplasmosis typically presents with consolidations, pulmonary nodules, or lymphadenopathy. Disseminated histoplasmosis usually presents with diffuse air-space opacities. Chronic histoplasmosis can show cavitary or calcified findings on imaging. Given this wide presentation, recognition and diagnosis of histoplasmosis is not based on imaging alone and the gold standard of diagnosis remains with culture or identification of Histoplasma spp. on histopathology.

Discussion: Our patient was initially diagnosed with COVID-19 approximately one month before her diagnosis of disseminated histoplasmosis. COVID-19 clouded her final diagnosis due to its similar presentation on imaging. Although there are documented cases of histoplasmosis infection presenting in adults as ARDS, this case details how a confounding diagnosis can delay the diagnosis of histoplasmosis until it has progressed to advanced disease with multisystem organ failure and ARDS resulting in death.