Mucormycosis - The black fungus
- Q. What is mucormycosis?
- Mucormycosis is a family of fungus that produces a disease in human beings
- It is popular on general and social media as the "black fungus"
- Q. Why is this black fungus making news these days?
- Right after the first wave of the COVID-19 infection, it was noticed that there was a sudden spurt in cases of mucormycosis in patients who had recovered from the COVID-19 infection.
- Q. What is the link between this black fungus and diabetes?
- Mucormycosis is generally a rare fungal disease
- Before 2020, most cases of mucormycosis were seen in people who had poorly controlled diabetes and developed diabetic ketoacidosis (a severe form of diabetes)
- Mucormycosis infection in people who do not have high sugars was considered rare.
- Q. Apart from diabetes, what is the second most common underlying risk factor?
- People having blood cancers
- Q. Do all patients with COVID-19 infection develop mucormycosis?
- Mucormycosis develops in those people with COVID-19 infection who develop high sugars
- This includes the following people:
- People already having poorly controlled diabetes and developing COVID-19 infection
- Those who did not have diabetes earlier, but developed high sugars after starting steroids in diabetes
- Those who had diabetes earlier, but was not diagnosed and developed COVID-19 infection
- Those who did not have diabetes earlier and did not receive steroids, yet developed high sugars after COVID-19 infection
- Q. What produces high sugars in COVID-19 infection in people who did not have diabetes earlier?
- COVID-19 infection itself is very well known to produce diabetes
- The virus is known to gain entry into the beta-cells of the pancreas which produces insulin
- Insulin helps to maintain normal sugars levels
- Since the cells which produce insulin are damaged- there is an increase of sugars due to the virus itself, especially those people having a serious infection
- Not all people develop diabetes after COVID-19 infection, some people who have a poor reserve of these beta-cells are more vulnerable to develop high sugars
- Patient given steroids
- Dexamethasone and Methylprednisolone are common steroids used in patients with COVID-19 infection
- These are life-saving drugs and hence NEED to be given to selected patients
- Steroids produce high sugars
- To know more about steroids follow this link: [[Basics about Steroids]]
- A combination of above
- In most patients who are hospitalized, the high sugar is a combination of both the above
- COVID-19 infection as well as the use of steroids
- This produces extreme sugar values
- Q. How do you differentiate between a person who already had diabetes before the COVID-19 infection and did not know about it versus those who developed high sugars secondary to the steroids and COVID-19 infection?
- This is done using a simple blood test called HbA1c
- This is a simple and easily available test - it is available in most labs in India
- If the HbA1c is more than 6.5% - it suggests that the person already had diabetes but did or did not know about it
- If the HbA1c is less than 6.5% it suggests that the patient did not have diabetes earlier but developed high sugars secondary to COVID-19 infection with or without steroid use.
- Q. Where does the fungus specifically grow in patients having COVID-19 infection with high sugars?
- The fungus tends to grow in the nasal cavity and the surrounding sinuses
- These can then spread to nearby areas including the orbit of the eye and even to the brain
- Q. Where are these fungi found in nature?
- They are ubiquitous (meaning widely spread)
- They are often found in decaying vegetation and the soil
- Q. Q. Do people with an intact immune system develop mucormycosis?
- Only people with compromised immunity develop mucormycosis
- High sugars produce this situation of compromised immunity
- Mucormycosis is also known. to occur in people who have certain blood cancers
- Q. Why is mucormycosis called the "black fungus"?
- This fungus is "angioinvasive" which means it gains entry into the blood vessels of the body and then lives happily there
- The blood flow in the smaller blood vessels is interrupted and hence the area which is supplies does not get adequate blood supply
- This lead to the tissue becoming gangrenous and black
- Typically the nose and the nasal mucosa show a characteristic black discoloration
- Q. Q. Broadly what are the risk factors for Mucormycosis?
- Diabetes mellitus with Ketoacidosis
- Use of Deferoxamine (an iron-chelating agent)
- Increased iron stores
- Treatment with steroids
- COVID-19 infection with high sugars with or without steroid use
- Use of injectable narcotics
- Poor nutrition
- Blood cancers
- Q. Do all patients with Mucormycosis have pre-existing diabetes?
- Lets put it this way, all patients with diabetes do not develop mucormycosis, however, MOST patients with mucormycosis have high sugars (except for those having other reasons for poor immunity)
- 30-40% of patients have pre-existing diabetes and many of the others are diagnosed to have new onset of diabetes or high sugars
- In the era of COVID-19, the development of Mucormycosis has been rampant, especially in patients having steroid and COVID-19 induced diabetes
- Q. Why has the incidence of mucormycosis in diabetes reduced in many countries before the onset of the COVID-19 era?
- The incidence of mucormycosis in diabetes has reduced considerably before it has resurgence with COVID-19
- It is mainly due to better control of blood sugars
- However, one theory is that this is because of the widespread use of statins (popularly used cholesterol medications) in diabetes patients
- Statins have an inhibitory effect on the growth of these fungi
- *"Exposure of R. oryzae to statins at concentrations below their MICs decreased virulence both in vitro and in vivo. Further investigation is warranted into the use of statins as adjunctive therapy in mucormycosis"
- - Q. What are the common sources of Mucor in hospital settings?
- Oxygen supply lines
- Hospital linen
- Nearby construction sites
- Tongue depressors
- Adhesive tapes
- Q. Do patients who are home treated with COVID-19 also have the risk of mucormycosis?
- In fact, since the last few months, we have seen a large number of patients who developed mucormycosis when they were home treated
- Q. What are the symptoms of mucormycosis (how do you recognize mucormycosis)?
- The symptoms of mucormycosis resemble sinusitis
- Nasal discharge- often blackish
- Nasal congestion
- Sinus pain
- Q. What is the typical clinical tell-tale sign for Rhino-cerebral mucormycosis?
- These patients have a characteristic 'black eschar' in the nasal mucosa
- Q. Can it involve the eye?
- It typically produces
- Swelling near the eyes
- Popping out of the eyes (proptosis)
- Q. What is another frequent facial sign seen in these patients?
- These patients complain of numbness of the face
- This is because of the involvement of a nerve which passes through this area
- Q. Can it spread to the brain?
- This could be very dangerous and potentially lethal
- Q. How can we diagnose this fungus?
- It is mainly diagnosed with clinical examination and if required a CT scan or MRI of the sinus, eyes, and brain
- MRI is more useful if brain involvement is suspected
- Q. Broadly, what is the treatment of Mucormycosis?
- Three things are essential
- Surgical removal of the fungus
- Antifungal injections and medicines
- Good sugar control
- Q. Which antifungal injection is given to these patients?
- These people are given an injection called amphotericin B
- Q. How long is the injection continued?
- For several weeks or months till all signs of fungus subsides
- Q. I have heard, that the amphotericin injection is very expensive, is this true?
- There are broadly two preparations of this injection -
- AMPHOTERICIN B DEOXYCHOLATE
- LIPOSOMAL AMPHOTERICIN B
- The general injection of AMPHOTERICIN B DEOXYCHOLAT is relatively cheaper, but it can cause kidney damage and hence cannot be used for a prolonged period
- LIPOSOMAL AMPHOTERICIN B is 10 times more expensive but does not produce kidney damage
- Q. Is the kidney damage due to AMPHOTERICIN B DEOXYCHOLATE reversible?
- It is potentially reversible
- There is a transient increase in creatinine in almost all patient but it often reverses when the injection is stopped
- Q. What can be done to prevent more cases of mucormycosis secondary to COVID-19 infection? (Expert opinion) ?
- 1. Rhino-oculo-cerebral mucormycosis is diabetes defining illness. Mucormycosis without diabetes or hematological disorder is very rare. Many of the patients with mucormycosis have undiagnosed diabetes mellitus. It is imperative that all patients with COVID-19 and all patients with mucormycosis be checked for Diabetes mellitus
- 2. Patients given steroids for home care or in hospitals must be checked for diabetes BEFORE starting the steroids. If they do have diabetes, the glucose should be intensely controlled. Expert opinion may be sought if the management of high sugars poses serious challenges.
- 3. Statins (cholesterol-lowering agents) may have a role in the prevention of mucormycosis. Administration of statins in patients with diabetes mellitus should be considered a priority.
- Date: Tuesday, 11 May 2021!
- - #Real-life-cases
- Patient with Mucormycosis post-COVID-19. The interesting thing about this patient is that the patient had uncontrolled diabetes mellitus and COVID-19 and home treated, **but was NOT GIVEN STEROIDS. **
- Hyperglycemia seems to be the important parameter for Post-COVID-19 mucormycosis and NOT steroids themselves