Black Fungus: Risk Factors, Prevention and Treatment

By- Dr. Sunil Kumar Kota

In the current times of COVID-19, the cases of black fungus is in upswing. Medically it is labelled as Mucormycosis. These are caused by 6 fungi in the Mucorales order, namely:Rhizopus, Mucor, Rhizomucor, Cunninghamella, Saksenaea, Apophysomyces. In the environment, these fungi are commonly found in wet soil, unclean water, compost and manure, Stored grains, rotten flower and leaves etc. The fungal spores predominantly enter into body by inhalation route, sometimes they enter via skin especially in people working in construction sites, engaged in farming and gardening. These cases occur usually after recovery & discharge of COVID 19 patients, but they can occur at any stage, even while the patient is admitted and getting treated for COVID-19.

Risk Factors:

This Fungal disorder is known since long and it predominantly affects people with compromised immunity including those with Diabetes (with prolonged uncontrolled sugars); injudicious use of long term steroids , antibiotics and antifungal voriconazole; chronic kidney, liver and lungs disorders; organ transplant (liver, kidney, bone marrow, stem cells) and immunosuppressive therapy; cancer (mostly blood cancers) & chemotherapy; AIDS, burn injury, Malnutrition; usage of iron chelating agent Desferoxamine etc. People engaged in construction work, farming, gardening, wood work are also more prone to develop this infection.The following can be common sources of Mucor in hospital setting including hospital linen, nearby construction sites, tongue depressors, adhesive tapes, intravenous canula.

The immunocompromised state of COVID-19 can also be a risk factor for Black fungus. Especially it is found in the affected people with moderate to severe forms of disease requiring steroids, long term oxygenation, prolonged mechanical ventilation and ICU stay, Tocilizumab treatment and those with elevated biomarkers like ferritin, interleukin-6. According to some recent literature,indiscriminate usage of Zinc and over indulgence in steaming can sometime harm our nasal mucosal surface giving easy passage to fungus to invade our body. Some doctors are of opinion that prolonged reuse of face masks for 2-3 weeks can also be a predisposing factor for black fungus. Only 30-40% of patients with Black Fungus have pre-existing diabetes. Some of the others are diagnosed to have new onset of diabetes. In the era of COVID-19, the development of Mucormycosis has been rampant, especially in patients having steroid-induced diabetes. People with high blood sugars have elevated free Iron and ketone in the blood, which are used by the fungus as feeding substrate. There is no age or sex predilection for this fungal disorder. Since all the immunocompromised states occur predominantly in adults to elderly, the fungal disorder is seen more commonly in those age groups. However, Children with any of the above conditions or blood cancers are equally prone. These cases occur usually after recovery & discharge of COVID 19 patients, but they can occur at any stage, even while the patient is admitted and getting treated for COVID-19.

Clinical Features:

It predominantly affects lungs (Pulmonary Mucormycosis). It also affects nose, eyes, jaws and brain (Rhino Orbito Cerebral Mucormycosis). These 2 forms are commonly seen in Diabetics. In people with extremely immunocompromised state, it can affect skin, gastrointestinal tract, kidney and then it can disseminate in to the whole body. When lungs get affected- there is fever, cough with or without sputum production, breathlessness. There can be other symptoms of nose- stuffy nose, dark nasal secretion (blackish/ bloody), one sided severe pain in the nose, jaw (cheek bone/ maxilla) and head; Eyes- swelling, redness around eyes and nose, bulging eye ball, blurred or double vision; Jaws- tooth ache, loosening of teeth, one sided facial pain over cheeks, numbness or swelling; Brain- altered mental status, Nerve paralyses, fits, paralyses; Stomach: Bloody vomitingEtc. Sometimes there can be development of a black patch over bridge of nose or palate (roof of mouth). Occasionally skin can get affected by intravenous canula giving rise to black patch (Eschar)

Prevention:

Proper Sugar control, avoidance of indiscriminate use of antibiotics, steroids, antifungal agents; use of sterile or distilled water for humidification of oxygen; avoidance of excess usage of zinc and steaming are some means proposed to protect one from any chances of infection. Exposure to moist, damp and dusty areas should be avoided. Similarly during gardening and visit to construction site, granaries; it is advisable to use masks, full sleeve shirts, long trousers, gloves while handling soil, shoes. Personal hygiene should be maintained through scrub bath

Diagnosis:

The specimen (tissue) is subjected for fungal staining (KOH staining), culture, PCR (Polymerase Chain Reaction) and MALDI=TOF test. The specimen can sometimes be obtained by deep nasal swab or nasal endoscopy. CT scan is useful for checking any bony erosions. However, MRI is more useful to detect brain involvement

Treatment:

The mainstay of treatment includes good sugar control, antifungal medications and surgical debridement. Antifungal treatment options include intravenous Amphotericin B (preferably liposomal form) followed by oral Posaconazole and Isavuconazole tablets. This has to be continued for several weeks (4-6 weeks)with periodic monitoring of kindey function, blood electrolytes. Surgical debridement is a cumbersome procedure lasting for about 4-5 hours for people with bone eroding form of Black fungus. In this procedure the dead portions of nose, orbit, jaw etc have to be surgically excises, which is quite disfiguring. Generally proper sugar control by Endocrinologist/ physician in addition to proper evaluation by experts from departments of ENT, Neuro surgery and Ophthalmology is needed. Early and timely identification of symptoms followed by diagnosis and proper treatment with antifungals can reduce the chances of debridement. Unless treated timely, this disorder is life threatening in 25-60% of cases.

Author: Dr. Sunil Kumar Kota, MD (Med), DNB (Endo), Consultant Endocrinologist, DIABETES & ENDOCARE Clinic, Berhampur, Email: [email protected], Ph: +917749804401

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