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Black Fungus (Mucormycosis) And COVID-19

Published on May 15, 2021 and last reviewed on Nov 08, 2021   -  4 min read


As the COVID pandemic and the newer variants of the pathogen are peaking globally, mucormycosis, a deadly fungal infection, is at a higher prevalence in COVID patients or those recovering from COVID. Read the article to know the causes, symptoms, prevention, and management of mucormycosis through proper oral hygiene and infection control.

Black Fungus (Mucormycosis) And COVID-19

What Is Mucormycosis?

Mucormycosis is a deep fungal infection that occurs primarily in two forms:

1) Acute.

2) Aggressive.

The majority of oral fungal infections arise mainly because of impaired host immune response and local pathological colonization. The infection, also known as "Black Fungus," is now a predominant risk factor for COVID-19 patients currently who either have uncontrolled diabetes mellitus or the cases where Intensive care unit/ICU stay is prolonged. This rare yet deadly fungal infection in COVID-19 cases especially affects the brain and lungs.

The cases of black fungus in COVID patients have been on the rise as the Government of India has issued an evidence-based advisory to the general public. The advisory mainly emphasizes that people who are on certain medications have a reduced ability to fight environmental pathogens.

How Does It Occur (Pathogenesis)?

The fungal spores primarily enter through the inhaled air, directly impacting the respiratory tract and lungs, open and cut wounds (when the spores enter through the skin), sinuses, or through lung infections. People suffering from immune disorders and people on immunosuppressant drugs are at a high risk of superficial to deep fungal infections in the oral tissues. Mucormycosis is caused by saprophytic fungi like Rhizopus, Mucor, Rhizomucor, Cunninghamella, Apophysomyces, Lichtheimia, or Saksenaea.

The fungal spores germinate within the host's immune system to generate hyphae by eventually invading the systemic tissues and creating clinical symptoms. Impaired immune functions in certain conditions like diabetic ketoacidosis can lead to accelerated growth of mucormycosis. Impaired phagocytic (cells for immune defense to fight bacteria and foreign organisms) functions, on the other hand, create more hyphae in the blood vessels leading to complications like ischemia, thrombosis, infarction, and tissue necrosis. There are mainly six well-recognized forms of mucormycosis:

  1. Pulmonary.
  2. Gastrointestinal.
  3. Central nervous system.
  4. Rhinocerebral.
  5. Cutaneous.
  6. Disseminated oral mucormycosis.

Disseminated oral mucormycosis is the manifestation currently in COVID-19 cases (blank fungus). It most often occurs in the nasal and paranasal sinuses of the face. Serious involvement of the paranasal sinuses of the face can thus result in palatal necrosis and ulceration, which is the most common oral diagnosis by the dental surgeon or oral and maxillofacial surgeons.

What Are the Symptoms and Risk Factors for Mucormycosis?

The major risk factors for mucormycosis in the current scenario of the peak wave of the pandemic is the following in a statement issued by the ICMR (Indian council of medical research):

  1. Prolonged ICU stay or prolonged duration of patients on ventilator support.
  2. Uncontrolled diabetes mellitus.
  3. Patients on immunosuppressants and steroid therapies.
  4. Malignancies and therapeutic agents or drugs used for it.
  5. Fungal infections of the oral cavity and Voriconazole therapy (an antifungal drug used as a therapeutic agent).

In COVID-19 patients with uncontrolled diabetes mellitus and immunosuppressed individuals, these symptoms are of particular importance to suspect a mucormycosis Infection:

  1. Sinusitis or inflammation of the nasal or paranasal sinuses.
  2. Nasal blockage and congestion.
  3. Unilateral or one-sided facial pain and numbness.
  4. Blackish discoloration of the bridge of the nose or on the palate of the mouth.
  5. Loosened teeth and painful tooth conditions.
  6. Chest pain that may be accompanied by worsening respiratory symptoms like breathlessness (increase in the number of breaths per minute, hypoxia or low oxygen saturation - PO2), wheezing, grunting, retractions, and color changes.
  7. Thrombosis (blood clots in different areas of the body that prevent normal blood flow).

Oral Hygiene Measures During and After Recovery From COVID:

According to the WHO, the SARS-COV-2 pathogen mainly spreads via tiny droplets that arise from an infected person's mouth when they cough, sneeze, talk, or laugh. Hence the oral cavity, which forms a major part of the immune defense against the novel Coronavirus, should be strictly maintained in hygiene. Doctors suggest the following measures as per the latest research, which indicates that the oral cavity can be a reservoir of microorganisms that maintain their viability for a significant period of time, ranging from 24 hours to 7 days. Microbial survival promotes the easy spread of fungal or viral pathogens into the oral cavity.

Brushing daily for a minimum of two minutes every day should not be ignored by COVID patients and those who have recovered from COVID.

  1. Toothbrushes should not be shared commonly nor be kept in a common holder as the virus has a tendency to replicate via infected surfaces.
  2. COVID-19 patients in a clinical setting are advised by physicians and dentists to rinse their mouth with Betadine gargle or regular antiseptic mouthwashes. In the absence of mouthwash, the patient can also rinse with warm saline water or warm salt water to ward off infection spread through the oral cavity.
  3. Disinfecting the toothbrush in an antiseptic solution while the patient is suffering from COVID also helps maintain infection control in a clinical setting or in-home quarantine.
  4. Post recovery from COVID, toothbrushes need to be disposed of and replaced by a new brush as the virus may have thrived on the bristles of the brush that can cause respiratory infections afresh.

Treatment Strategies for Mucormycosis:

Early detection and multidisciplinary treatment is the gold standard for physicians and maxillofacial surgeons to detect Mucormycosis. Controlling diabetes and modulating immunosuppressant drugs. Proper oral hygiene, diagnosis by the dentist, and relevant antifungal therapy to treat this fungal infection are useful in the further aggravation of the deadly fungus. As per government advisory, medical treatment once a COVID patient is infected with mucormycosis is mainly by insertion peripherally of a central catheter to maintain systemic hydration in the body. Infusion of normal saline and treatment with the drug Amphotericin B before infusion of the saline intravenously is also a mainline treatment.

The patient should be monitored thoroughly by the dentist and the physician in a COVID clinical setting while oral and physical examination. Radio imaging has also been useful in knowing the stage of disease progression of the fungus as it primarily impacts the brain and lungs though its manifestation is seen more in the oral cavity and the sinuses of the face. Hence self-medication by the COVID patients (or asymptomatic COVID patients who suspect a fungal infection for mucormycosis) is strictly not advisable. Without consulting a physician or maxillofacial or dental surgeon, the infection in the current scenario is indeed life-threatening.

Oral hygiene and standard is a major and crucial factor to recovery from this deadly fungal infection.

Last reviewed at:
08 Nov 2021  -  4 min read


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