Fungal sinusitis - causes, symptoms, and treatment
Updated: 3 days ago
How sinus infection is caused?
Sinusitis mostly happens when there is a stagnation of fluids in the sinuses. This can happen in two scenarios and can be classified into two types accordingly - allergic and bacterial sinusitis.
Whenever there is a stagnation of fluid in the sinus, bacteria will start growing in it, causing sinusitis. It is one way of resulting in sinusitis.
The other way is that a virement bacteria (strong bacteria) enters the nose and cause sinusitis without stagnated secretions.
Usually, it is rhinosinusitis, where the infection is in the nose and the sinuses causing inflammation of the sinus and nasal walls.
What causes fungal sinusitis?
One of the theories postulated was that when fluids stagnate in sinuses, bacteria grow in them. Our immune system will produce WBCs to kill these bacteria. These WBCs creep into the sinus secretions present in the infected sinuses. WBCs can successfully kill the bacteria, but they cannot go back into the blood, so they ideally have to be drained through the natural drainage process. But, due to the inflammation in the sinuses caused by sinusitis, the drainage has already been blocked, so the fluid containing a lot of dead bacteria and WBCs might find it difficult to escape the sinus. These fluids will turn into puss and become food for the fungus. Any organism to live requires food and water, making such sinuses an ideal hub for fungi growth. So the fungus which enters our body will thrive in these sinuses, causing fungal sinusitis.
Dead bacteria and WBCs in stagnated fluids of sinuses act as food for fungal growth and cause fungal sinusitis.
Types based on the nature of the infection
Fungal sinus infections can be broadly classified into 3 types based on the behavior of the disease but not on the type of fungi.
Non-invasive fungal sinusitis or localized fungal sinusitis
What is noninvasive fungal sinusitis?
The most common and least dangerous among the three types.
In noninvasive fungal sinusitis, the fungus is within the sinus cavity but doesn't enter the sinus wall or tissue.
To kill the fungus, we require killer cells in the body, which are in limited proposition. For example, one side of the army has 100 soldiers in a war, and the other has one lakh soldiers. Ultimately, the one lakh soldiers will win because there are phenomenally outnumbered. As the fungus multiplies fast and our body cannot produce enough killer cells at similar rates to tackle the fungus. So instead our body will continuously check to prevent the fungus from getting into the blood or tissue by creating a barrier around the sinuses. This process will continue for a very long time.
But whenever the body's immunity comes down for any reason, like, if there is a viral infection, the entire immune system will fight the viral infection. In such scenarios, the fungus doesn't have any obstacles to its progress. So it will multiply and enter tissues turning into an invasive fungal sinus infection. It is invasive fungal sinusitis if our immunity can curtail the situation. If our immunity cannot curtail the invasive fungal infection too, it turns into fulminant fungal sinusitis.
This is what exactly happened during covid. When the covid virus entered our bodies, it knocked off the immune system, which helped the fungus to escape our immune system's attention. By the time it tackled covid, it couldn't attack the multiplied fungus, which resulted in numerous mucormycosis cases. Mucormycosis is a fulminant type of fungal infection.
Types of non-invasive fungal sinusitis
The non-invasive fungal sinusitis can be of two types:
Allergic fungal rhinosinusitis
In allergic fungal rhinosinusitis, most problems are due to allergies. The fungus is very limited in number, but the body overreacts to the fungus. Usually, in allergic fungal rhinosinusitis, there will be a strong allergic reaction from the body to minimal fungus. If there is no reaction, then the fungus will increase.
Fungal ball in sinuses
In a fungal ball, there will be a massive amount of fungal material, and the body will not respond. The body responds to an outside organism in two ways one is an allergic type, and another is killing one. If the allergic type is more, they will develop allergic fungal rhinosinusitis. If the response for the body is very negligible, then it grows into a fungal ball.
The Symptoms of Non-invasive Fungal Sinus infection
In the initial stages of non-invasive fungal sinusitis, the symptoms are similar to a bacterial sinus infection or regular sinus infection.
Phlegm oozes from the nose to the back of the throat, thus a need to clear the throat.
Frequent attacks of cough
These symptoms are very mild or even absent, so it is hard to identify non-invasive fungal sinusitis. Even if we have symptoms, they are because of bacterial sinusitis, not because of the fungus, which lives silently in the sinuses.
Sometimes the fungus starts to flare up whenever the immunity is compressed, and at that point, the sinus wall will give way to the fungus. That could be the wall between the eye & sinus or the sinus & brain. The fungus will spread to adjacent places and start pressuring the important structures of the eye or brain, but it will not spread to them. Due to the pressure on the eye and brain, there will be symptoms related to the eye or brain. In this case, we can identify it using endoscopy and CT scans.
There are many cases where patients get CT scans for other purposes and find fungal sinusitis. Because when there is no secondary infection, the symptoms are always less or even absent. So we don't even know we have a fungal infection unless we get a CT scan.
Diagnosis for non-invasive fungal sinusitis
As mentioned in the symptoms section of this article, it is not possible to identify non-invasive fungal sinusitis based on the symptoms. Even if the symptoms are shown they are mostly allergic reactions or symptoms of bacterial sinusitis that coexist with the fungal sinus infection.
Endoscopy and CT scan
We diagnose the non-invasive fungal sinusitis by performing an endoscopy and CT scan. Suppose after doing an endoscopy if we find any fungal material coming from the sinus into the nose. In that case, we send it for culture and examination under a microscope to identify if there is a fungal infection. Also, by doing different mycological studies, we can identify the type of fungus.
Fungal smear, also known as a potassium hydroxide smear. In this, we take a drop of puss obtained in endoscopy and put it on a glass side along with potassium hydroxide. Potassium hydroxide can kill or dissolve the cell wall of bacteria or other organisms. So after waiting for some time, all the cell walls get dissolved. But, the fungus can withstand the potassium hydroxide solution, so these cells will remain, making it easy to identify or observe the fungus. Food, water, and proper temperature are provided to the fungus for two to 14 days. The fungus will grow from one spore to a full-grown plant making it easy to determine the type of fungus it is, depending on its character.
Treatment Options for Fungal Sinus Infection
Non-Invasive Fungal sinusitis treatment
Fungal ball non-invasive treatment
For fungal ball patients, we have to open the sinus wherever we have a fungal ball it must be opened to drain the fungus. We have to widen the natural ostium of the sinus so that in the future there is no scope for the stagnation of fluids. We already know that fungus will grow in the stagnated fluid. If we don't allow the fluid to stay in the sinus, the fungus cannot form, so we have to make a big opening so that the fluids can come out easily.
Allergic fungal rhinosinusitis
In allergic fungal sinusitis, most complaints are because of the allergic reaction. So there will be a lot of polyps, secretions coming into the nose, sneezing, itching in the nose, and phlegm or fluid going into the different parts of the nose causing complaints.
Initially, in this scenario, we give antiallergic medication, which brings down the symptoms. Sometimes, we prescribe steroids to reduce inflammation. And finally, we perform surgery to clear the sinus and remove the stagnated fluid. We have to widen the sinus opening so that there will be no stagnation of fluids in the future. If we don't allow the fluid to stay in the sinus, the fungus won't grow, which decreases allergic reactions.
Antifungal treatment for non-invasive fungal sinusitis
Suppose the fungal number is more in the fungal ball or even in the allergic fungal rhinosinusitis. In that case, we use antifungal medications to support the treatment. But it is not the primary treatment. For the fungal ball, we need to give the antifungal medicine and the surgery. In allergic fungal rhinosinusitis, the antifungal medication should go along with the antiallergic medications and surgery.
Invasive fungal sinusitis & Fulminant invasive fungal sinusitis
Although fulminant is an invasive type of fungal sinusitis when we say invasive fungal sinusitis we always refer to the non-fulminant type only.
Invasive fungal sinusitis
Unlike non-invasive, invasive, the fungus spreads into the tissues and doesn't remain confined to the sinus making it dangerous compared to non-invasive. Invasive is a rare type of fungal infection and occurs only when a person's immunity is down.
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Fulminant invasive fungal sinusitis
Although the fulminant fungal infection is a subtype of invasive sinusitis, when we say invasive, we usually refer to non-fulminant invasive fungal sinusitis. The immunity needs to go even lower in fulminant fungal infection. In these infections, the fungus just doesn't spread through tissues but also through blood vessels making it not just comparatively dangerous to non-invasive and invasive, but also life-threatening.
Mucormycosis is the most common type of fulminant fungal infection. It is commonly known as black fungus infection. Fulminant fungal infection can be caused by the below-listed fungi.
Candida (causes Candidiasis)
COVID-19 is one of the diseases that can trigger fulminant fungal sinusitis. They are famously known as post-COVID black fungus (mucormycosis caused by mucor) and post-COVID white fungus cases (fulminant sinusitis caused by candida or aspergillosis).
Pre-COVID, fulminant fungal sinusitis is even rarer than invasive fungal sinusitis.
Comparison of invasive and fulminant fungal sinusitis
In invasive fungal sinusitis, it takes more time to spread. Although most of the initial symptoms are the same, the difference between these two types is so evident, that an ENT doctor can differentiate by just looking at the timeline of the symptoms.
For fulminant invasive fungal sinusitis, major debridement surgeries are unavoidable, whereas for invasive, only a minor biopsy is done as a part of the diagnosis but not as treatment.
Although invasive fungal sinusitis is more dangerous than non-invasive fungal sinusitis, surgeries are not required to treat invasive sinusitis. We treat it with antifungal medication because, in invasive sinusitis, the fungus is in the tissue, where the antifungal medication can reach and kill the fungus. Whereas in allergic or non-invasive sinusitis, the fungus is in the sinus cavity where the antifungals cannot reach, so surgical removal of the fungus is required.
On the contrary, for fulminant, the fungal spread is so quick, and immunity is so low that powerful antifungals alone won't be sufficient to handle the fungus. An ENT doctor performs multiple debridements and gives a good dosage of antifungals to treat this disease. This process is clearly explained in our article dedicated to mucormycosis treatment.
Is fungal sinusitis an emergency?
Fulminant fungal sinusitis is a rapidly spreading condition, capable of reaching the brain and killing a person within weeks. Its rapid progression results in the doubling of fungal growth within hours. While this is a rare form of fungal sinusitis, it can be seen only in individuals with weakened immunity.
Invasive, which is also rare, is not an emergency due to a slow spread. Although it is life-threatening, it can take years to reach the brain.
Non-invasive can become an emergency only when it affects the eyes and brain.
What kills sinus fungus?
Antifungals or any medication cannot kill the fungus if it is constrained to the sinuses because the fungus is inaccessible to drugs.
Does fungal sinusitis require surgery?
Yes, if the fungal sinusitis is non-invasive or fulminant invasive types. For a typical invasive fungal sinusitis, only a small biopsy will be required for diagnostic purposes but not treatment.
Will a CT scan show fungal sinusitis?
CT scans can show fungal contents inside the sinuses and help in diagnosis.
We can see a gray shadow with white color shadows inside the sinuses. You can check out our diagnosis article for more details.
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