A fatal post-COVID-19 sino-orbital mucormycosis in an adult patient with diabetes mellitus: a case report and review of the literature

Abstract

Introduction: COVID-19 is associated with a broad spectrum of bacterial and fungal superinfections.

Case presentation: We present a case of mucormycosis developing during post-COVID-19 therapeutic management. A 63-year-old diabetic female presented with COVID-19 and received combination therapy per institutional protocol, including dexamethasone, remdesivir, and ivermectin. Seven days post-discharge, the patient was readmitted with dyspnea and lethargy. On day 3 of readmission, the patient reported unilateral facial and orbital pain. Subsequent histopathological and mycological examination confirmed mucormycosis. Despite surgical debridement and treatment with amphotericin B (3 mg/kg/day), the patient succumbed to the infection.

Results: Based on ITS rDNA sequencing, the fungus was identified as Rhizopus arrhizus. Antifungal susceptibility testing was performed according to the CLSI M38-A2 guideline, yielding minimum inhibitory concentration (MIC) values of 0.016 µg/mL for amphotericin B, 0.031 µg/mL for posaconazole, 0.25 µg/mL for isavuconazole, 1 µg/mL for itraconazole, and 8 µg/mL for voriconazole.

Conclusions: Early diagnosis, prompt antifungal therapy, and appropriate surgical intervention are critical for improving mucormycosis outcomes, especially in COVID-19 patients.

Keywords: COVID-19; corticosteroids; diabetes mellitus; mucormycosis; sino-orbital; zygomycosis.