Black fungus is a severe invasive fungal infection caused by RHIZOPUS typically seen in immunocompromised individuals.
There has been an increased incidence of this fungal infection in patients suffering from COVID 19 disease.
Several factors including underlying diabetes, immunosuppressives, host factors, pancreatic endocrine dysfunction by COVID 19 have been proposed as the putative causative mechanisms for Mucormycosis.
However, the judicious use of steroids and/or other immunosuppressants should not be withheld in patients with severe COVID 19, as they can be life-saving.
Treatment is long term and involves a combination of drugs and surgical measures.
Mucormycosis, popularly termed “Black fungus” by the media and public, is a disease caused by ubiquitously occurring mold found in decaying vegetation and soil. It leads to necrotic black tissue at the infected sites, hence the name. In the Indian setting, it was more commonly seen in uncontrolled diabetics or people on extensive immunosuppression. We have seen the surge in cases of Mucormycosis during this COVID pandemic. We have also published such an initial series of patients (http://dx.doi.org/10.18203/issn.2454-5929.ijohns20211583). There have been several reasons proposed for this sudden surge in the deadly fungus.
Prolonged use of steroids and other immunosuppressives
Inborn errors of immunity
COVID19 could affect the pancreas which in turn can disturb the glycemic balance leading to prolonged periods of increased sugar levels in these patients. Thus, Mucormycosis can also be seen among COVID affected patients who were not treated with steroids or other immune-suppressing drugs.
Mucormycosis is caused by Rhizopus oryzae, the most common fungus responsible for the disease which causes about 70% of the cases. Despite advanced treatment and aggressive therapy, the mortality rate of the black fungus disease is over 50%. Further, the mortality rate in disseminated disease or with persistent neutropenia is even higher. The condition requires urgent and aggressive medical intervention; else it may result in debilitating or fatal consequences.
People with the following conditions/procedures are at increased risk for developing black fungus disease:
Uncontrolled diabetes mellitus in ketoacidosis
Organ or bone marrow transplantation
Malignant hematologic disorders
Other forms of metabolic acidosis
Treatment with corticosteroids
Trauma and burns
Deferoxamine therapy in patients receiving hemodialysis
The cause of black fungus is due to exposure to mucormycetes mold. The fungus is present in the soil, rotting wood, a pile of compost, and leaves.
You may contract black fungus infection through the skin. If you have any cut or scratch on the skin and comes in contact with the fungus, you may get black fungus disease.
Another way of developing this condition is through pulmonary exposure via inhaling the mould spores. Through inhalation, you may have an infection in your lungs and sinuses that may progress to the brain, eyes, and face.
However, not all people exposed to these moulds develop this disease. People with low immunity are at high risk for developing black fungus disease.
Black fungus is not a contagious disease and does not spread from animals to the human. The fungal spores are present in the environment, including air. In most cases, when the person inhales these spores, they are attacked and destroyed by the immune system. However, in immunocompromised patients, the moulds survive and cause infection.
Some of the black fungal symptoms are:
Sinus and respiratory: Sinus, oral cavity and nasal involvement with extension to the eye is the commonest type of presentation.
Skin Infections: Due to cut, scratches or burnt skin, there is an exposure of the inner tissue to the black fungus. It may result in symptoms, such as ulcers, redness, swelling, tenderness, blisters, and blackened skin tissue.
Brain Infection: Disseminated black fungus infection in the brain may result in coma or altered mental status.
Ocular infection: Infection of black fungus in the eyes may result in eye pain, redness, swelling, blurred vision, and blindness. In some cases, there is a need to remove the eyes to prevent the progression of infection.
Gastrointestinal Infection: Black fungus infection in the gastrointestinal tract may result in Nausea and vomiting, abdominal pain, and gastrointestinal bleeding.
There are various methods to diagnose black fungal disease. Some of them are:
Clinical diagnosis: Headache is the most common presenting feature. Tissue necrosis is the evident clinical sign and looking out for eschar (black scab) in the oral or nasal cavity helps in diagnosing the same. Redness and protrusion of the eye with swelling along with the loss of vision, severe facial pain and focal numbness should raise the suspicion of the disease
Imaging Techniques: CT Scan of paranasal sinuses and brain helps in picking up the rhino- orbital disease. CT lungs can help in looking for pulmonary nodule and effusion helps in diagnosing pulmonary disease.
Histopathological and microbiological examination: Identifying the fungus on the microscopic examination of the tissue and looking for uptake of special attains to identify the fungus is the most important step in diagnoses
Molecular assays: Molecular assays, such as restriction fragment length polymorphism analyses (RFLP), conventional polymerase chain reaction (PCR), melt curve analysis of PCR products, and DNA sequencing of defined gene regions, helps in determining the presence of Mucorales (pathogen responsible for black fungus disease). These tests are not commonly carried out as usually microscopic examination suffices
Management of black fungus disease requires a comprehensive approach. It includes managing the underlying predisposing factors, removing the necrotic tissues, initiating antifungal treatment, and adjunctive therapy. Following are the methods to manage black fungus disease:
Antifungal medications: The doctor may prescribe various antifungal medications. Some of them are liposomal amphotericin B, isavuconazole, and posaconazole.
Surgical debridement: Several infection specialists believe that surgical debridement of the infected part is required to save the patient's life. It helps in preventing the progression of the disease. After the successful outcome of treatment, the patient may undergo plastic surgery.
This disease usually has prolonged treatment duration and the drugs used are toxic, expensive and requires a long-term hospital stay. Apart from this, procurement of these lifesaving drugs has become problematic due to a sudden spike in the demand.
It can lead to severe comorbidities such as vision loss, focal deficits and even death at times particularly when the disease is not adequately treated at the early stages.
Having a high index of suspicion helps!!
If diagnosed early it can be treated better with improved outcomes.
Taking care of diabetes and having well-controlled sugars are the most important factor to prevent the invasion. Staying in touch with your endocrinologist and the ID physician post-COVID is also critical.
Following hygienic measures and frequent hand wash with minimizing the exposure of the fungal spores to the mucosal surface is also important.
You must take good care of yourself if you have compromised immunity. You should bandage all your wounds and use a mask while working in the yard. One must understand that steroid can be a lifesaving drug while managing COVID and shouldn’t shy away from its optimal use.
Frequently Asked Questions
Mucormycosis is a rare fungal disease caused by a group of molds called mucormycetes. It mainly affects people who are on medication for health problems and are immuno-compressed. Usually, people with a healthy immune system does not pose threat to mucormycetes.
The excessive use of steroids and antibiotics and the contamination through the pipes and prongs used for the mechanical supply of oxygen to patients are the main reason for rising in black fungus. Mucormycosis is not contagious which means it does not spread from one person to another. The fungal infection can also occur if clean masks are not worn and the rooms are not ventilated properly.
The black fungus disease symptoms depend on the part of the body it has infected.
Symptoms of sinus and brain (rhinocerebral mucormycosis) include:
One-sided facial swelling
Nasal or sinus congestion
Black lesions on the nasal bridge
Symptoms of pulmonary (lung) mucormycosis include:
Shortness of breath
Symptoms of Cutaneous (skin) mucormycosis include:
Blisters or ulcers
Excessive redness, or swelling around a wound
Symptoms of gastrointestinal mucormycosis include:
Nausea and vomiting
Where is mucormycosis found?
Mucormycetes are particularly found in soil and in leaves, compost piles, and animal dung. They are more common in soil than in the air.
Mucor is a microbial genus usually found in soil, organic decaying matter and old, damp carpets where moisture levels are high enough. They are white or greyish in color and grow rapidly.
First intravenous (IV) antifungal medications (amphotericin B, posaconazole, or isavuconazole) are given to the patient and then surgery is performed to cut away the infected tissue.
One may catch mucormycosis when the fungus enters the skin through a cut, burn or any other types of skin problems. The black fungus sticks to a body part and travels inwards through the nose, sinus or lungs.
If the fungus goes through the sinus, it can affect the eyes and the brain which can lead to a fatal situation.
In Covid-19 patients, their airway mucosa and blood vessels are damaged and serum iron is increased which results in a favourable environment for the black fungus to grow. Steroids are given to covid-19 patients which increases the sugar levels and the long term ventilation reduces the immunity of the patients. These all factors create a favourable environment for the fungus to grow and infect the patient.
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