Mucormycosis, also known as black fungus,
/ref> that comes under fulminant fungal sinusitis,[ It is curable only when diagnosed early.][ It most commonly infects the Human nose, paranasal sinus, Human eye and Human brain resulting in a rhinorrhoea, one-sided facial swelling and pain, headache, fever, diplopia, bulging or displacement of the eye (proptosis), and necrosis.]
It is spread by spores of mucoromycotina of the order Mucorales, most often through inhalation, contaminated food, or contamination of open wounds.[ Risk factors include diabetes with persistently high blood sugar levels or diabetic ketoacidosis, neutropenia, cancer, organ transplant, iron overload, renal failure, long-term corticosteroid or use of immunosuppressants, and to a lesser extent in HIV/AIDS.][
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Diagnosis is by tissue biopsy and culture, with medical imaging to help determine the extent of disease.[ Treatment is generally with amphotericin B and debridement.]
Mucormycosis is usually rare,[ but is now ~80 times more common in India.][ The first known case of mucormycosis was possibly the one described by Friedrich Küchenmeister in 1855.][ The disease has been reported in , including the 2004 Indian Ocean tsunami and the 2011 Joplin tornado.][ A rise in cases was particularly noted in India.]
Classification
Generally, mucormycosis is classified into five main types according to the part of the body affected.[ or miscellaneous, i.e., mucormycosis at other sites, although less commonly affected.]
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Paranasal sinus and brain (rhinocerebral); most common in people with poorly controlled diabetes and in people who have had a kidney transplant.
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Lungs (pulmonary); the most common type of mucormycosis in people with cancer and in people who have had an organ transplant or a stem cell transplant.
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Stomach and intestine (gastrointestinal); more common among young, premature, and low birth weight infants, who have had antibiotics, surgery, or medications that lower the body's ability to fight infection.
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Skin (cutaneous); after a burn, or another skin injury, in people with leukaemia, poorly-controlled diabetes, graft-versus-host disease, HIV and Drug injection.
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Widespread (disseminated); when the infection spreads to other organs via the blood.
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Signs and symptoms
Signs and symptoms of mucormycosis depend on the location in the body of the infection.[ Infection usually begins in the mouth or nose and enters the central nervous system via the eyes.][
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If the fungal infection begins in the nose or sinus and extends to the brain, symptoms and signs may include one-sided eye pain or headache and may be accompanied by pain in the face, numbness, fever, hyposmia, a nasal congestion or coryza. The person may appear to have sinusitis.
Fever, cough, chest pain, and dyspnea, or hemoptysis, can occur when the lungs are involved.[ A Abdominal pain, nausea, vomiting, and bleeding can occur when the gastrointestinal tract is involved.]
Invasion of the Blood vessel can result in thrombosis and subsequent necrosis due to a ischemia.[ Widespread (disseminated) mucormycosis typically occurs in people who are already sick from other medical conditions, so it can be difficult to know which symptoms are related to mucormycosis. People with disseminated infection in the brain can develop changes in mental status or lapse into a coma.]
Cause
Mucormycosis is a Mycosis caused by Fungus in the order Mucorales.[ In most cases it is due to an invasion of the genus Rhizopus and Mucor, common bread molds.]
The fungal spores are present in the environment, can be found on items such as moldy bread and fruit, and are breathed in frequently, but cause disease only in some people.[ In addition to being breathed in and deposited in the nose, sinuses, and lungs, the spores can also enter the skin via blood or directly through a cut or open wound, and can also grow in the intestine if eaten.][ Once deposited, the fungus grows hyphae which invade , causing thrombosis and surrounding necrosis.][ Other reported causes include contaminated wound dressings.][ Mucormycosis has been reported following the use of elastoplast and the use of for holding in place intravenous catheters.][ Outbreaks have also been linked to hospital bed sheets, negative-pressure rooms, water leaks, poor ventilation, contaminated medical equipment, and building works.]
Risk factors
Predisposing factors for mucormycosis include immunodeficiency, a neutropenia, and metabolic acidosis.[ Risk factors include poorly controlled diabetes mellitus (particularly DKA), organ transplant, iron overload, such as , kidney failure, cirrhosis, severe malnutrition, and long term corticosteroid and immunosuppressive therapy.][ Other risk factors include tuberculosis (TB),][ deferoxamine][ Cases of mucormycosis in fit and healthy people are less common.][
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Corticosteroids are commonly used in the treatment of COVID-19 and reduce damage caused by the body's immune response to the virus. They suppress the immune system and increase blood sugar levels in both diabetic and non-diabetic patients. These effects may increase a person's vulnerability to developing a case of mucormycosis.
Mechanism
Most people are frequently exposed to Mucorales without developing the disease.[ Mucormycosis is generally spread by inhalation, eating food contaminated by, or getting spores of molds of the Mucorales type in an open wound.][ It is not transmitted between people.][
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The precise mechanism by which diabetics become susceptible is unclear. In vivo, a high sugar level alone does not permit the growth of the fungus, but acidosis alone does.[ People with high sugar levels frequently have high iron levels, also known to be a risk factor for developing mucormycosis.][ In people taking deferoxamine, the iron removed is captured by on Rhizopus species, which then use the iron to grow.][
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Diagnosis
No blood test can confirm the diagnosis.[ Because the causative fungi occur all around and may therefore contaminate cultures underway, a culture alone is not decisive.][ Tests may also include culture and direct detection of the fungus in lung fluid, blood, serum, plasma, and urine.][ Blood tests include a complete blood count to look specifically for neutropenia.]
Imaging
Radiology is often performed, such as CT scan of lungs and sinuses.[ Currently, MRI with gadolinium contrast is the investigation of choice in rhinoorbito-cerebral mucormycosis.
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Culture and biopsy
To confirm the diagnosis, biopsy samples can be cultured.
File:Zygomycosis, mucormycosis 2.jpg|Ribbon-like hyphae which branch at 90°
File:Zygomycosis Mucormycosis (13430751363).jpg|Hyphae in blood vessel
File:Mature sporangium of a Mucor sp. fungus.jpg|Mature sporangium of a Mucor
Other
Matrix-assisted laser desorption/ionization may be used to identify the species.
Differential diagnosis
Other filamentous fungi may however look similar.
Prevention
Preventive measures include wearing a face mask in dusty areas, washing hands, avoiding direct contact with water-damaged buildings, and protecting skin, feet, and hands where there is exposure to soil or manure, such as gardening or certain outdoor work.[ In high-risk groups, such as organ transplant patients, may be given as a preventative.][
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Treatment
Treatment involves a combination of antifungal drugs, Debridement and correcting underlying medical problems, such as diabetic ketoacidosis.[
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Medication
Once mucormycosis is suspected, amphotericin B at an initial dose of 1 mg is initially given slowly over 10–15 minutes into a vein, then given as a once daily dose according to body weight for the next 14 days.
Surgery
Surgery can be very drastic, and, in some cases of disease involving the nasal cavity and the brain, removal of infected brain tissue may be required. Removal of the palate, nasal cavity, or eye structures can be very disfiguring.[
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Other considerations
The disease must be monitored carefully for any signs of re-emergence.[ Hyperbaric oxygen may be considered as an adjunctive therapy because higher oxygen pressure increases the ability of neutrophils to kill the fungus.][ The efficacy of this therapy is uncertain.]
Prognosis
It tends to progress rapidly and is fatal in about half of sinus cases, two-thirds of lung cases, and almost all cases of the widespread type.[ Skin involvement carries the lowest mortality rate of around 15%.][ Possible complications of mucormycosis include the partial loss of neurological function, blindness, and thrombosis of blood vessels in the stroke or lung.]
As treatment usually requires extensive and often disfiguring facial surgery, the morbidity after surviving, particularly sinus and brain involvement, is significant.[
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Epidemiology
The true incidence and prevalence of mucormycosis may be higher than appears.[ and where its incidence has been rising.][ It is the third most common serious human fungal infection, after aspergillosis and candidiasis.]
Diabetes is the main underlying disease in low and middle-income countries, whereas blood cancers and organ transplantation are the more common underlying problems in developed countries.[ As new immunomodulating drugs and diagnostic tests are developed, the statistics for mucormycosis have been changing.][ In addition, the figures change as new genera and species are identified, and new risk factors are reported, such as tuberculosis and kidney problems.][
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COVID-19–associated mucormycosis
[[File:Map of COVID-associated Mucormycosis (Black fungus) cases.png|thumb|
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During the COVID-19 pandemic in India, the Indian government reported that more than 11,700 people were receiving care for mucormycosis as of 25 May 2021. Many Indian media outlets called it "black fungus" because of the black discoloration of dead and dying tissue the fungus causes. Even before the COVID-19 pandemic, rates of mucormycosis in India were estimated to be about 70 times higher than in the rest of the world.
Recurrence of mucormycosis during COVID-19 second wave in India
Pre-COVID mucormycosis was a very rare infection, even in India. It is so rare that an ENT (ear, nose, throat) doctor would often not witness a case during their education. So, the documentation available on the treatment of mucormycosis is limited. There used to be a few mucormycosis expert ENT surgeons for millions of people before the pandemic. The sudden rise in mucormycosis cases has left a majority of ENT doctors with no option but to accept mucormycosis cases, as the expert doctors were very much occupied, and the patient would die if left untreated. The majority of the ENT doctors had to manage with minimal or no experience on mucormycosis, which has led to the recurrence of mucormycosis in the patients they treated. When a highly experienced doctor in mucormycosis treats a patient even if he cannot guarantee that the individual is completely cured and will not have a relapse of mucormycosis; an inexperienced ENT surgeon will have a high number of patients with recurrence due to which there were many recurrent cases of mucormycosis although it did not get the limelight of media or the Indian Government.
History
The first case of mucormycosis was possibly one described by Friedrich Küchenmeister in 1855.
In 1953, Saksenaea vasiformis, found to cause several cases, was isolated from Indian forest soil, and in 1979, P. C. Misra examined soil from an Indian mango orchard, from where they isolated Apophysomyces, later found to be a major cause of mucormycosis.
Naming
Arnold Paltauf coined the term " Mycosis Mucorina" in 1885, after describing a case with systemic symptoms involving the sinus, brain, and gastrointestinal tract, following which the term "mucormycosis" became popular.[ (several authors)]
COVID-19–associated mucormycosis
COVID-19-associated mucormycosis cases were reported during the first and second(delta) waves, with the maximum number of cases in the delta wave.
Other countries affected included Pakistan,
Society and culture
The disease has been reported in natural disasters and catastrophes; 2004 Indian Ocean tsunami and the 2011 Missouri tornado.[Williams, Timothy (June 10, 2011) Rare Infection Strikes Victims of a Tornado in Missouri. New York Times.]
In 2014, details of a lethal mucormycosis outbreak that occurred in 2008 emerged after television and newspaper reports responded to an article in a pediatric medical journal.
Other animals
Mucormycosis in other animals is similar, in terms of frequency and types, to that in people.
Further reading
External links
