Risks of mucormycosis in the current Covid-19 pandemic: a clinical challenge in both immunocompromised and immunocompetent patients

Abstract

Mucormycosis, also called "Black Fungus", is a new cause for worry in the current Coronavirus disease 2019 (covid-19) pandemic. Mucormycosis is devasting due to its high rate of morbidity and mortality which is a great cause of concern. Mucormycosis, in general, affects immunocompromised patients including diabetic, people with malignancies, organ and stem cell transplants and people affected with pandemic diseases like covid-19. Diagnosis of Mucormycosis is often delayed either due to clinical complications or misdiagnosed as symptoms of other diseases, especially covid-19. This could delay the treatment protocol which results in the failure of treatment. Mortality rate due to secondary infections in covid-19 patients with uncontrolled diabetics and who are on steroid therapy can soon reach 100% if diagnosis and treatment doesn't happen on timely basis. Risk of Mucormycosis is not just in immunosuppressed patients, but immunocompetent people with late diagnosis are also prone to infection. In view of this, we present a comprehensive review on risks of Mucormycosis in immunocompromised and immunocompetent patients highlighting the epidemiology, forms of Mucormycosis, immune response against Mucorales, difficulties in diagnosis and challenges in treatment of Mucormycosis, with emphasis on covid-19 associated Mucormycosis. Importantly, we have discussed the precautions and care to effectively manage Mucormycosis in immunocompromised and immunocompetent patients. Thus, current review helps clinicians in understanding various risk factors in both immunocompromised (especially covid-19 patients) and immunocompetent patients which is critical in managing Mucormycosis in current covid-19 pandemic.

Keywords: Black fungus; Covid-19; Immunocompetent; Immunocompromised; Mucormycosis; Risks of mucormycosis.

Fig. 1

Reported case studies of different forms of Mucormycosis (A). Survival and Mortality rate in different forms of Mucormycosis (B). Global epidemiology of prevalence of Mucormycosis (C). Major risk factors that cause Mucormycosis in India and globally (D). ROCM Rhino-orbito-cerebral Mucormycosis; HSCT Hematopoietic stem cell transplantation; SOT solid organ transplantation

Fig. 2

Proposed scheme for cause of Mucormycosis in both immunocompromised and immunocompetent patients. The Mucorales species (approximately 27 different types) are known to cause the infection. Initially the spores released by Mucorales enter the body deep into the tissues either by ingestion, inhalation or percutaneous injection of spores. Soon after the infection, the immune cells are recruited to fight against the foreign agents. However, due to influence of various risk factors (internal, external, local and systemic) as shown in the figure, immune sytem fails to fight against the organism and result in immune disregulation or immune system breakdown. This results in a disease called ‘Mucormycosis’. Mucormycosis can affect various vital body organs including skin, nose, eyes, face, mouth and lungs. They cause various symptoms which can vary from minor amputations to major symptoms including depletion of organs and even death. This disease can be prevented or treated by timely diagnosis and effective treatment methods

Fig. 3

Representative clinical signs and symptoms of Mucormycosis in patients. Image Source:[–65]