Mucormycosis: The Scathing Invader

Mucormycosis is an invasive fungal infection that has been increasing in incidence over the years. Increase in the number of diabetics, malignancy patients, and use of immunosuppressants has mainly led to this gradual upward surge. Mucormycosis has various clinical forms, including rhino-orbito-cerebral, pulmonary, gastrointestinal, and cutaneous. Fungi belonging to Mucorales are thermotolerant and ubiquitous, found growing on organic substrates such as bread, decaying fruits and vegetables, crop debris in soil, compost, and animal excreta. During this second wave of the COVID-19 pandemic, the number of cases of mucormycosis has increased manifold in a short span of time. Associated comorbidity of diabetes mellitus, increased use of higher doses and prolonged duration of systemic corticosteroids, the glucogenic and prothrombotic propensity of the virus, hypoxic environment, COVID pneumonia, increased hospitalization, ICU admissions, and mechanical ventilation have all contributed toward this high rise in numbers. The rhin-orbito-cerebral form is the commonest manifestation of mucormycosis in COVID. Rhizopus oryzae, the main species causing mucormycosis, is identified by hyaline, sparsely-septate, broad, ribbon-like hyphae with irregular right-angle branching ribbon-like hyphae with rhizoids. For the early diagnosis of this infection, 10% KOH mount is very important. These fungi are very rapidly growing and thus can be differentiated from their main ally, Aspergillus. Treatment is mainly in the form of extensive surgical debridement along with liposomal amphotericin B. Posaconazole and isavuconazole are second-line agents, which can also be used for maintenance. Control of diabetes and COVID-19, along with judicious use of antibiotics and systemic corticosteroids, are equally important as management strategies in these pandemic times.