Everything You Need to Know About Mucormycosis - 'The Black Fungus'

Introduction:

Mucormycosis is a fungal infection caused by a group of molds called mucormycetes. It is also known as Zygomycosis. It is a serious but rare fungal infection and is also referred to as a black fungus. It usually affects the sinuses or the lungs after inhaling fungal spores from the air. It mainly affects people with comorbidities or those who have weakened immunity.

What Are Mucormycetes?

Mucormycetes are a group of fungi that cause fungal infections. It is usually present throughout the environment, especially in the soil, and in association with decaying organic matter such as leaves and animal dung. They are more commonly seen in soil than in the air and seen mostly during summer than in winter. These fungi are not harmful to most people.

What Are the Other Types of Fungi That Causes Mucormycosis?

There are many different types of fungi that belong to the scientific order Mucorales and cause mucormycosis. The most common types are:

• Rhizopus species.

• Mucor species.

The other types of fungi that cause mucormycosis are:

• Rhizomucor species.

• Syncephalastrum species.

• Cunninghamella Bertholletia.

• Apophysomyces.

• Lichtheimia.

Who Is More Prone to Mucormycosis?

People who are more likely to get Mucormycosis are the

• People with weak immune systems.

• Diabetes.

• Ketoacidosis.

• People with organ transplants.

• Long-term usage of corticosteroids.

• Neutropenia (low white blood cell -WBC) count.

• It can occur on the skin after an injury or cut or any burn.

• Hemochromatosis (an excessive amount of iron in the body).

• Premature birth and low birth weight (in case of neonatal gastrointestinal mucormycosis).

How Do People Get Mucormycosis?

Mucormycetes is present throughout the environment. When people come in contact with these mucormycetes, they inhale the fungal spores from the air. It mainly affects the lungs and sinuses. It can also cause a skin infection when fungus enters the skin through a cut or through any other type of skin injury.

Is Mucormycosis Contagious?

Mucormycosis usually does not spread from person to person. It also does not spread between people and animals.

What Are the Signs and Symptoms of Mucormycosis?

There are five clinical forms of mucormycosis in which; the two most common clinical forms are:

• Rhinocerebral mucormycosis.

• Pulmonary mucormycosis.

And the other clinical forms are:

• Gastrointestinal mucormycosis.

• Cutaneous mucormycosis.

• Disseminated mucormycosis.

1) Rhinocerebral Mucormycosis:

Rhinocerebral mucormycosis starts as an infection in the sinus and then leads to swelling of the nerves in the brain. It causes blood clots in the brain. It is a fungal infection that involves the sinus and the brain. It is commonly seen in patients with diabetes, neutropenic patients, and renal transplants.

The symptoms seen are-

• Unilateral facial swelling.

• Headaches.

• Nasal or sinus congestion.

• Nasal discharge.

• Fever.

2) Pulmonary Mucormycosis:

Pulmonary mucormycosis is a lung infection. The common symptoms of pulmonary mucormycosis are-

• Fever.

• Chest pain.

• Cough.

• Shortness of breath.

3) Gastrointestinal Mucormycosis:

Gastrointestinal mucormycosis is less common than the other types of mucormycosis. It occurs after the ingestion of the organism. It usually occurs in malnourished patients and premature children. The parts that are affected are-

• Stomach.

• Ileum.

• Colon.

The symptoms are-

• Nausea.

• Vomiting.

• Non-specific abdominal pain.

• Abdominal bleeding.

It is usually challenging to diagnose as it has similar clinical features as necrotizing enterocolitis (a disease that affects the newborn’s intestines).

4) Cutaneous (Skin) Mucormycosis:

Mucormycosis may appear as small blisters or ulcers. This infected region turns black in color. The symptoms seen are-

• Swelling in that infected area.

• Pain.

• Warmth.

• Redness around the wound.

5) Disseminated Mucormycosis:

Disseminated mucormycosis occurs in people who are already suffering from other medical illnesses as the symptoms become difficult to diagnose if it is related to mucormycosis or any other existing medical illnesses. There are chances of a coma state for patients with disseminated mucormycosis in the brain.

How Is Mucormycosis Usually Diagnosed?

The healthcare professionals consider the previous medical conditions and the clinical symptoms. A sample of fluid is collected from the lungs or sinuses and sent to the laboratory to detect the fungal species.

Doctors may also perform a tissue biopsy if needed.

Imaging tests like CT (computed tomography) scans of lungs and sinuses can be recommended depending on the area of mucormycosis.

What Is the Treatment for Mucormycosis?

Mucormycosis is treated with antifungal drugs. It can be given either intravenously or orally. The drugs that are given intravenously are:

• Amphotericin B.

• Isavuconazole.

• Posaconazole.

Isavuconazole and Posaconazole can also be given orally.

There are certain drugs that cannot treat mucormycosis. It includes:

• Fluconazole.

• Voriconazole.

• Echinocandins.

But the drugs should be taken only after the doctor’s consultation.

If necessary surgical debridement or resection can be recommended, particularly for rhinocerebral, cutaneous, and gastrointestinal mucormycosis.

How Is the Prognosis of Mucormycosis?

The prognosis of mucormycosis depends on the overall health condition of the patient and the body’s response to the treatment. Early diagnosis and treatment can give better outcomes, but if not treated or identified early, the overall mortality rate is 50 %.

How Can Mucormycosis Be Prevented?

As mucormycetes are present throughout the environment, it is difficult to avoid inhaling the fungal spores from the air. There is also no vaccine available to prevent mucormycosis. People with weakened immunity or other medical conditions or illnesses can follow these steps to lower the chances of mucormycosis.

• Avoid areas with a lot of dust. If a person cannot avoid them, then wear a mask when going to these areas.

• Avoid activities that involve contact with dust or soil. If this is not possible, then:

  • Try wearing gloves while handling.

  • Wear long-sleeved clothes.

  • Clean the injuries with soap and water. Keep it clean.

Why Is Mucormycosis Seen in COVID-19 Patients?

Studies show that mucormycosis is seen in a few COVID patients. COVID-19 is a severe disease caused by SARS-CoV-2 and commonly occurs in patients with weak immunity and also elderly patients. Elderly patients are more likely to have medical conditions like diabetes, hypertension, and other renal issues, which makes them more prone to opportunistic fungal infections like mucormycosis. It is because the fungal spores (Mucor species) grow well in an environment (host) with the following characteristics:

• Low-oxygen.

• Acidic medium.

• High glucose.

• Decreased immunity.

In addition, health experts consider steroids a life-saving treatment for severe and critically ill COVID-19 patients, whereas steroids suppress immunity and trigger mucormycosis, and the overall mortality rate of mucormycosis is 50 %. Therefore, the above-mentioned factors increase the risk of mucormycosis inCOVID patients.

Conclusion:

Mucormycosis is a rare but serious fungal infection. Early diagnosis, predisposing risk factors, and appropriate treatment, which includes prompt prescription and administration of antifungal medications, can have a better prognosis and outcomes. In addition, vaccination against COVID-19 should be encouraged with prompt management of diabetes, hypertension, and other renal abnormalities in patients to decrease the risk of mucormycosis.