Mucormycosis, also known as the black fungus, a rare coronavirus linked fungal infection that affects the sinuses, brain and lungs. It is life-threatening in diabetic patients, cancer patients and immune-suppressed patients. Recently they have found many cases of black fungus associated with post covid patients. Therefore, if the progression of this fungus not checked, it may even lead to mortality in 50-80% of the cases. Hence, this article highlights the black fungus, its different types, various cases reported, and its management and prevention.
WHAT IS MUCORMYCOSIS?
Mucormycosis is an infection caused by mucormycetes belonging to the order Mucorales. However, it is worldwide in distribution and the organism occurs in soil, manure, fruits, and decaying matter. And also these organisms are present in the nasal passages and oral cavities of normal persons.
It is more common in diabetic patients. More than 75% of the cases have been reported in diabetic ketoacidosis (DKA). Recently they have found that unbound iron in serum plays an important role in predisposing patients with DKA to mucormycosis.
WHY IT’S COMMON IN DIABETIC PATIENTS?
In the presence of increased blood sugar level(hyperglycemia) and low pH, found in patients with diabetic ketoacidosis (DKA), phagocytes (macrophages) have defective intracellular killing by both oxidative and non-oxidative mechanisms.
When the macrophages cannot kill the microorganism entering the body, its oxidative mechanism becomes defective. Hence, invasion of this fungus is even easier in diabetic patients.
COMMON ORGANISM ASSOCIATED:
Rhizopus oryzae, the most common organism isolated from patients with mucormycosis and responsible for 70% of cases.
- Uncontrolled diabetes mellitus
- Treatment with corticosteroids
- Organ or bone marrow transplantation.
- Neutropenia (that is reduction in neutrophil count)
- Trauma (injury )and burns
- Malignant hematologic disorders
This opportunistic infection associated with debilitation and more frequently associated as the second occurrence in covid patients. Covid patients have to take corticosteroids for their treatment, Consequently, this suppresses the immunity and acts as a predisposing factor in transmitting this fungus.
PATHOGENESIS OF MUCORMYCOSIS:
Mucormycosis infections characterized by extensive angioinvasion. To clarify, the black fungus invades the blood vessel and causes vessel thrombosis and subsequent tissue necrosis (that is leading to the death of the tissue).
This ischemic necrosis of the infected tissue can prevent the delivery of leukocytes and anti-fungal agents to the foci of infection( that is infected area where transmission of infection occurs termed as foci of infection).
Moreover, the ability of inhaled sporangiospores to germinate and form hyphae in the host is very critical for establishing infection.
TYPES OF MUCORMYCOSIS:
There are five types of mucormycosis they are :
- Rhino cerebral
This type of mucormycosis is more common in diabetic patients. It occurs due to the inhalation of the sporangiospores into the sinuses.
The fungus invades the cranium through the orbital apex or the cribriform plate of the ethmoid bone. Consequently, there will be rapid spread to the adjacent structures and ultimately leads to the death of the host.
The initial symptoms include sinusitis and periorbital cellulitis. Further, it includes facial numbness, pain followed by blurred vision. The mortality rate of rhino cerebral type is 30-70%.
This type of mucormycosis seen in immune-suppressed patients, cancer patients, patients receiving chemotherapy, etc.
The patients present with a prolonged high-grade fever that is unresponsive to broad-spectrum antibiotics. The patient experiences a dry cough.
Recently, they have found that pulmonary type, rhino cerebral type of mucormycosis has been reported in post covid recovered patients. The mortality rate is 50-70%.
This occurs due to direct inoculation of fungus into the skin leading to this type of mucormycosis.
When the fungus involves only the skin and subcutaneous tissue is termed as local invasion. Similarly, when it invades muscle, tendons, bones it is termed as a deep invasion.
This type usually slow and progressive, moreover fulminant spread leads to gangrene (localized death of tissue leading to severe infection) and hematogenous spread to the tissues.
This type is rare. Most commonly the stomach is affected.
The fungus can invade the bowel walls, blood vessels hence resulting in bowel peritonitis, sepsis, and massive gastrointestinal haemorrhage ultimately leading to death. The mortality rate is 85%
Pulmonary variants are common in this type. It is the most fatal type. Moreover, patients with iron overload, immune-suppressed, decreased production of neutrophils and leukaemia have disseminated variant.
A metastasised skin lesion is the most important hallmark for this type and also a sign for early diagnosis. The mortality rate is 90%.
SIGNS AND SYMPTOMS:
Pain and redness around eye or nose
- Dry cough
- Shortness of breath
- Bloody vomits
- Altered mental status.
- Facial swelling
- Paresthesia (numbness)
- Discoloration of the skin (turns black)
- Sinus tract opening near the orbit. (the narrow elongated opening that extends from the wound filled with fluids)
- Foul-smelling nasal discharge
- Nasal congestion
- Halitosis (bad breath or oral malodour)
- Intra oral pus discharge
- Exposed palatal bone
- Loosening of tooth, toothache.
- Blurred vision, therefore leading to vision loss.
- Peri orbital cellulitis
- Proptosis (protrusion of eye or forward projection of eye)
- Ophthalmoplegia (Paralysis of eye muscle restricting eye movement)
INVESTIGATIONS FOR MUCORMYCOSIS:
CBC (Complete blood count):
Monitor blood glucose levels after covid infection are very important to detect the black fungus. Hence a complete blood count test is the best to detect any sort of infection in the body.
Haemoglobin A1C is the measure of glycated haemoglobin. It is an important test for diabetic patients. This gives an indication of how controlled their diabetes is. This is a 6-month indication of blood sugar level in the body. Therefore post covid, diabetic patients are advised to take this test to know their blood glucose level.
ESR(Erythrocyte sedimentation rate):
Erythrocytes in the blood is an indication of infection. This blood test detects how quickly the erythrocytes settle at the bottom of the test tube. This gives an idea of any active infection in the body.
FBS(Fasting blood sugar test):
8 hours of fasting is mandatory before drawing blood for fasting blood sugar.
LFT(liver function test):
This test also known as the hepatic panel test , is group of blood test which provides information about the state of liver and its functions.
RFT (Renal function test ):
This test assess the renal functioning. Also known as the kidney function test or KFT.
CT AND MRI:
These imaging modalities are very important to detect the nodal involvement and nodal infiltration.
GOLDEN STANDARD FOR DIAGNOSIS:
A biopsy is the removal of tissue from the part of the body for microscopic examination and diagnosis purposes. Hence biopsy is considered the golden standard procedure. We can find the organism microscopically and arrive at the diagnosis.
The smear collected from the black fungus affected area is examined in potassium hydroxide. Other stains like eosin and haematoxylin, Grocott silver methenamine are also used for hyphae detection.
The fungus appears as large, non septate hyphae with branching at obtuse angels with round or ovoid sporangia.
MANAGEMENT OF MUCORMYCOSIS:
Injectable amphotericin B is used to treat mucormycosis. Liposomal antifungals have better renal tolerance. Further, anti-fungal drugs as per the doctor’s prescription are indicated.
Surgical management is needed if involvement is severe .
GUIDELINES TO PREVENT THE BLACK FUNGUS:
Firstly, monitor the blood glucose level, post covid discharge. Similarly in cases where increased blood sugar level is seen consult your doctor immediately.
USE STEROIDS JUDICIOUSLY:
Use steroids very carefully, follow the correct timings, correct dose, and duration with proper guidance of your doctor since it increases your blood sugar level and also suppreses your immunity.
AVOID VISITING DUSTY/ MOISTY AREAS:
Use masks if you are visiting your gardens, wear shoes, long trousers, long sleeve shirts while handling soil, since the black fungus distributed in the soil. Further, this climate is very favourable for fungus growth.
USE STERILE WATER FOR HUMIDIFIER DURING OXYGEN THERAPY:
Oxygen through a humidifier that uses water from the tap may contain many types of organism. This may lead to the formation of the fungus. Therefore, people must use sterile water in humidifiers and change the water twice in 24 hours. It is also important to keep the humidifiers clean.
DO NOT IGNORE THE SIGNS AND SYMPTOMS:
In case you have any symptoms of mucormycosis immediately consult your doctor. Do not ignore the signs and symptoms.
MAINTAIN PERSONAL AND ENVIRONMENTAL HYGIENE:
Ensure personal hygiene by bathing and scrubing the body thoroughly , particularly after returning home from work, after work outs , visiting neighbours, relatives and friends.
Wear face masks, face shields when going through a polluted environment like a construction site. Make sure to wear fully covered clothing with full sleeves, gloves, shoes, when coming in contact with the garden areas, soil, etc.
CONSUME DIET WHICH BOOSTS UP YOUR IMMUNITY:
Every day consume diet that boosts up immune level. In addition turmeric, garlic, ginger, and lots of proteins to your diet increase your immune level. Hence, stay hydrated consume lots of water, consume carbohydrates in a minimal amount.
RECENTLY REPORTED CASES:
Mucormycosis cases have been reported across India. 12 cases have been reported in Madurai, 14 cases have been reported in Pondycherry in a private eye hospital with symptoms of blurred vision and increased blood sugar level. In the last two weeks, Bengaluru has nearly 75 cases of black fungus, Pune records the highest of 270 cases reported.
Delhi, Gujarat, Uttar Pradesh, Rajasthan have also detected its cases. Recently mucormycosis was reported in 22 old young men who were affected with pneumonia and severely immune suppressed. The availability of Amphotericin B drug has spiked in recent days.
To conclude, taking care of personal hygiene post covid is very important to prevent this deadly black fungus. Further, monitoring blood glucose level is very essential to boost your immune level by consuming an energy-rich protein diet. Hence, follow the guidelines will definitely prevent the deadly black fungus. Stay safe and healthy.