Mucormycosis in COVID-19 Patients: Everything you should know

Black Fungus Infection Causes, Symptoms, Risk Factors and Treatment
18.May.2021

What is Mucormycosis?

Mucormycosis or Black Fungus disease is a life-threatening but rare fungal infection caused by mucormycetes. The mucormycetes are a group of molds belonging to the order Mucorales. The fungi that have been isolated from more than 70% of cases of mucormycosis is Rhizopusoryzae. Patients suffering from diabetic ketoacidosis, neutropenia, and organ transplantation have weakened immunity. They are susceptible to Mucormycosis. When the immunity is low, and the necessary defense mechanism to fight such fungal infection is absent, then even a cut on the skin, burn, or other types of skin injury gives the fungal spore a free way to enter inside the body. There are three ways humans can contract Mucormycosis:

  • By inhaling spores, or
  • By swallowing spores in food or medicines, or
  • When spores contaminate wounds

Out of the three ways, inhalation of spores is the most common way to get infected with this fungal disease.

Fungal spores, when gets deposited in the nasal cavity, lead to rhinocerebral disease. Similarly, spores attacking the lungs lead to pulmonary disease, or entering the intestine leads to GI disease. Finally, if they enter through cuts in the skin, they lead to cutaneous disease.

How Mucormycosis is Related to Covid-19?

The disease pattern of COVID-19 can range from mild to life-threatening pneumonia with associated bacterial and fungal coinfections. A human body may breathe in the spores of many known and unknown fungi on a typical day. Thanks to the healthy lungs and the immune system of humans, that prevents those spores from causing any infection.

A weakened immune system and an infected lung, as in the case of COVID-19, leads to the easy entry of fungal spores into the body to germinate and attack the tissues. Mucormycosis is most often spread across the nose and sinuses. It can then be applied to the eyes, causing blindness or the brain, causing headaches or seizures.

Pathogenesis of Mucormycosis

The human body has phagocytes (neutrophils) whose primary function is to protect the body against fungal attacks similar to Mucormycosis. It has been found scientifically that patients who lack phagocytes or have impaired phagocytic function are at higher risk of mucormycosis. In the absence of phagocytes, these mucoraceae spores begin to germinate when they enter the body. Upon germination, they form fungal hyphae that attack the blood vessels, producing tissue infarction, necrosis, and thrombosis. Similarly, when R. oryzae sporangiospores are inhaled into an immunocompromised patient's lungs, the pulmonary alveolar macrophages are unable to prevent sporangiospores germination.

In addition to this, there is another trait of R. oryzae that helps it cause the disease. It is the ability to acquire iron from the host. Fungi can obtain iron from the host by using high-affinity iron permeases or low-molecular-weight iron chelators (siderophores). Rhizopus is known to secrete rhizoferrin, a siderophore that supplies Rhizopus with iron through a receptor-mediated, energy-dependent process.

Risk Factors Associated with Mucormycosis

Mucormycosis does not affect every patient who has contracted COVID-19 or is on treatment or those who have recovered recently. Patients with the following risk factors are more prone to get this fungal disease that includes:

  • Diabetes mellitus and uncontrolled sugar intake in the diet.
  • People with comorbid disorders who have been taking immunosuppressive steroid drugs for a more extended period to treat pre-existing diseases, as well as COVID-19.
  • Being admitted to a hospital's Intensive Care Unit for an extended period.
  • Presence of comorbidities like the history of organ transplant operations or cancer treatment procedures that decreases the strength of the immune system.
  • Those patients who are already taking prescription antifungal drugs like Voriconazole to combat infections.

Warning Signs and Symptoms

Once the fungal spores are inhaled, they invade the sinuses or lungs of the patient. This leads to severe disease with the following warning signs and symptoms:

  • Pain and redness around eyes or nose
  • The bridge of the nose/palate turns blackish
  • Blurred vision with pain, fever, skin lesion, thrombosis, and necrosis
  • Headache
  • Coughing
  • Shortness of breath and chest pain
  • Bloody vomits
  • Altered Mental Status
  • One-sided facial pain, numbness, or swelling.

Prevention and Management

Mucormycosis can be prevented if people obey the COVID guidelines. Avoid crowded places, wear a mask, maintain social distancing, and take vaccination on time. The Telangana government has issued guidelines to prevent Mucormycosis in COVID-19 Patients. As per the guidelines, control of sugar intake in COVID-19 infected, treatment ongoing, and recovered patients should be monitored in their diet. Apart from that, physicians are advised to use steroids, antibiotics, or antifungals judiciously at the correct dose and correct duration. Finally, the government has stressed cleaning the humidifier with clean, sterile water and dry air during oxygen therapy. The ICMR has also given guidelines to manage Mucormycosis. The guidelines are almost similar to the guidelines by the Telangana government. Apart from that, ICMR advises doctors to discontinue Immunomodulatory drugs, stop antifungal prophylaxis, and infuse normal saline IV before Amphotericin B injection for treating Mucormycosis.">COVID guidelines. Avoid crowded places, wear a mask, maintain social distancing, and take vaccination on time. The Telangana government has issued guidelines to prevent Mucormycosis in COVID-19 Patients. As per the guidelines, control of sugar intake in COVID-19 infected, treatment ongoing, and recovered patients should be monitored in their diet. Apart from that, physicians are advised to use steroids, antibiotics, or antifungals judiciously at the correct dose and correct duration. Finally, the government has stressed cleaning the humidifier with clean, sterile water and dry air during oxygen therapy. The ICMR has also given guidelines to manage Mucormycosis. The guidelines are almost similar to the guidelines by the Telangana government. Apart from that, ICMR advises doctors to discontinue Immunomodulatory drugs, stop antifungal prophylaxis, and infuse normal saline IV before Amphotericin B injection for treating Mucormycosis.

References

  1. Evidence based advisory in the time of COVID-19. Accessed at https://www.icmr.gov.in/pdf/covid/techdoc/Mucormycosis_ADVISORY_FROM_ICMR_In_COVID19_time.pdf
  2. Mucormycosis. Accessed at https://www.cdc.gov/fungal/diseases/mucormycosis/index.html
  3. Mucormycosis: What to Know. Accessed at https://www.webmd.com/lung/mucormycosis-black-fungus-infection
  4. Ibrahim, A. S., Spellberg, B., Walsh, T. J., &Kontoyiannis, D. P. (2012). Pathogenesis of mucormycosis. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 54 Suppl 1(Suppl 1), S16–S22. https://doi.org/10.1093/cid/cir865
  5. Mucormycosis/Black Fungus: Why Are COVID-19 Patients At Risk? Accessed athttps://www.netmeds.com/health-library/post/mucormycosis-black-fungus-why-are-covid-19-patients-at-risk-here-are-icmr-guidelines-for-prevention
  6. Mucormycosis: An emerging challenge in Covid-19 management. Accessed at https://health.economictimes.indiatimes.com/news/industry/mucormycosis-an-emerging-challenge-in-covid-19-management/82507750
  7. Telangana government releases guidelines for control of Mucormycosis. Accessed athttps://www.thehindu.com/news/national/telangana/telangana-government-releases-guidelines-for-control-of-mucormycosis/article34566928.ece

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