Mucormycosis is an infection caused by fungi belonging to the order Mucorales. Mucormycosis is a life-threatening infection that occurs in patients who are immunocompromised because of diabetic ketoacidosis, neutropenia, organ transplantation, and/or increased serum levels of available iron. Because of the increasing prevalence of diabetes mellitus, cancer, and organ transplantation, the number of patients at risk for this deadly infection is increasing. Despite aggressive therapy, which includes disfiguring surgical debridement and frequently adjunctive toxic antifungal therapy, the overall mortality rate is high. With the world reeling under the throes of a submicroscopic, enigmatically animated infectious particle, the novel coronavirus, we are now having to contend with another hitherto not so common opportunistic foe the so-called “ Black fungus” infection, academically christened mucormycosis. The most brutal, ruthless manifestation being Rhino-orbito-cerebral mucormycosis(ROCM).
Mucormycosis is an infectious disease caused by a fungus of the class of Zygomycetes and the order of Mucorales.
The species most frequently isolated from patients are Apophysomyces (A. variabilis), Cunninghamella (C. bertholletiae), Lichtheimia [Absidia] (L. corymbifera L. raosa), Mucor (M. circinelloides), Rhizopus (R. arrhizus (oryzae) R. microsporus), Rhizomucor (R. pusillus), and Saksenaea (S. vasiformis). These are common environmental organisms that are not harmful to humans who are immunocompetent. In patients with overt immunocompromise (i.e., transplant patients, HIV, patients of chronic steroids or disease-modifying anti-rheumatic medications, leukemia or other cancer patients), they can present with rapidly progressive necrotizing infection. Similarly, uncontrolled diabetics (particularly those with a history of diabetic ketoacidosis) are also at risk.
Generally, some types of fungi don't cause any infections in humans but can cause sickness in people with weakened immune systems known as opportunistic infections.
Some most common types of fungal infections are:
The fungi can also affect the gastrointestinal system, renal systems and can cause a full-blown infection resulting from the entry of fungus into the bloodstream.
Mucormycosis can occur any time after COVID-19 infection, either during the hospital stay or several days to a couple of weeks after discharge.
The COVID-19 causes favourable alteration in the internal milieu of the host for the fungus and the medical treatment given, unwittingly also abets fungal growth. COVID-19 damages the airway mucosa and blood vessels. It also causes an increase in the serum iron which is very important for the fungus to grow. Medications like steroids increase blood sugar. Broad-spectrum antibiotics not only wipe out the potentially pathogenic bacteria but also the protective commensals. Antifungals like Voriconazole inhibit Aspergillosis but Mucor remains unscathed and thrives due to lack of competition. Long-term ventilation reduces immunity and there are speculations of the fungus being transmitted by the humidifier water being given along with oxygen. All the above make for a perfect recipe for mucormycosis infection.
These infections are very lethal, and if not treated most will not make it. The mortality ranges between 25 to 90%. Once the infection spreads into the brain mortality is very high. Hence a lot of importance is given to early diagnosis and prompt institution of treatment.
How to prevent the occurrence of ROCM?
Prevention is always better than cure.
Post-Covid, during recovery, if a patient develops sinus headache, facial pain, stuffy nose, bloody nasal discharge, blackish discoloration over nose or palate, eye pain, swelling, diminished of vision or double vision, tooth pain, headache, seizures, drowsiness, limb weakness then immediate medical help must be attained.
The key take-home messages are opportunistic fungal infections are occurring in COVID-19 patients, awareness among health care providers and the public is important, early diagnosis and aggressive treatment are paramount for improving outcomes in an otherwise dismal disease, together we can definitely win this battle against COVID 19 and mucormycosis.