The Rapidly Fatal Black Fungus: Mucormycosis

 Dr. SR Narahari, Director, Institute of Applied Dermatology, Kasaragod, Kerala

In recent years ringworm or itchy fungus of thighs has spread across the country. However, Mucormycosis is a different fungus because when affected, it causes death in about 50 to 85% of patients in a very short period and severe disability in those who survive. Since the fungus looks black under the microscope, it is called the black fungus. A precise diagnosis is possible only by culturing the sample by the microbiologists.   It is seen in people who are suffering from chronic low immunity (immunocompromised).

Although it occurs in patients with uncontrolled diabetes, patients on dialysis and anti-cancer drugs, a sudden increase happened following COVID 19 disease. One reason could be that many people infected by corona disease might be seen commonly now. Patients receive additional steroids to combat corona in the hospital and receive a low nutrient diet during the hospitalization triggering the increase in number. One crucial difference is that the fungus attacks in diseases where neutrophils of white blood cells are not functioning correctly (viral infections). So, despite the many AIDS patients we had two decades ago, the black fungus was not prevalent because of reducing white lymphocyte cell in HIV.

Unfortunately, it is a killer fungus. It enters the body using any breach in skin or mucosa that means common sites are eyes, nose and mouth. It starts as a thick brownish spot around the nose, a black spot inside the nose or palate (late presentation). It may initially look like red-eye and swollen eyelids. Patients may not be able to move eyeballs or complain of blurred vision, eye pain, or normal but sudden vision loss. The retinal examination will show what is called a Cherry red spot.  There could be brown or bloody nasal discharge, foul smell, loss of teeth etc. Suddenly it eats up the optic nerve (loss of vision), invasion of cavities and sinuses around the nose, damaging the bones and eventually invading the brain and death. Technically named Rhino-Orbital-Cerebral Mucromycosis (ROCM). In severe cases, it eats up the tissue, fits etc., leading to death. Mucormycosis is a medical emergency. This fungus commonly grows over the kitchen bread. It can also infect the intestine, presenting as diarrhoea, especially when uncontrolled diabetic patients each such pieces of bread after cleaning it. When lungs get, infected patients may also present with blood-stained sputum. The disease is rapidly fatal, and doctors begin treatments when the condition is suspected, even before all reports are made available. Treatments include Amphotericin injections and Posoconozole. The drug price per day may vary from 10,00 to 25,000. If the patient survives, six months of treatment is required.

The fungus requires iron for its growth. Mucormycosis has a particular liking for blood vessels and alveoli of the lungs because haemoglobin contains iron. During viral infection, especially COVID 19, there is a functional alteration of neutrophils. This results in a series of enzymatic reaction in the tissues, releasing free iron from haemoglobin and other iron stores in the body to tissues and blood. Hence the fungus quickly surrounds and invades the blood vessel stopping the blood supply to the area causing local necrosis (death) of the tissue. Dead skin looks black in colour. Horrific injuries happen as fungus invades inside for more iron, and fungal heaps are seen in the sinus mucosal layer and nasal cavities. Drugs can not remove these heaps of fungal growth. Because mucormycosis invades blood vessels, heroic surgical treatment on the affected area is often required. So, nasal, palate and maxillary bones will have to be cut open to remove the fungal heaps (called debridement). All bones below the eyes till the jaw are removed, and if the patient survives, a prosthesis would have to be given. This requires a multi-disciplinary team to manage; ENT, Ophthalmology, Neurosurgeon, Physician, Maxillo-Facial Surgeon, Anaesthetist, Pathologist, microbiologists working together in a high technology surgical support facility.