An insight into the pathophysiology of mucormycosis: Lesson learnt during COVID pandemic

Abstract

Mucormycosis, a lethal fungal infection caused by Rhizopus oryzae, has gained significant attention due to its association with the COVID-19 pandemic. The causal relationship between COVID-19 and mucormycosis is not yet fully understood. This narrative review focuses on the pathophysiology of mucormycosis, particularly in the context of COVID-19. Mucormycosis primarily affects immunocompromised individuals and is commonly observed in diabetic patients with COVID-19 who receive high doses of corticosteroids. The most common presentation of mucormycosis in COVID-19 is rhino-orbital-cerebral mucormycosis. Early diagnosis and prompt initiation of treatment, including extensive surgical intervention and appropriate antifungal therapy, are crucial in preventing fatal complications. The global prevalence of mucormycosis varies widely, with a higher incidence in developing countries such as India. Diabetes mellitus remains the leading risk factor globally, while COVID-19 and corticosteroid therapy also predispose immunocompromised patients to mucormycosis. The impaired phagocytic activity in immunosuppressed individuals and the ability of Mucorales to acquire iron from the host play significant roles in the pathogenesis of mucormycosis. Endothelial damage and thrombosis, along with hyperglycemia, acidosis, and increased serum iron levels observed in COVID-19, contribute to the aggressive nature of mucormycosis in these patients. The review emphasizes the need for further research to establish a causal association between COVID-19, corticosteroid therapy, and mucormycosis, and highlights the importance of understanding the underlying mechanisms to improve the management and outcomes of patients with this devastating fungal infection.