What is Fungal Sinusitis?
Fungal sinusitis, an infection in the sinus, comes in various types, depending on how much the sinus is invaded by the fungus. There are two main categories: non-invasive and invasive sinusitis caused by fungus.
The non-invasive type has three subtypes: Fungal Ball (FB), Saprophytic Fungal Sinusitis (SFS), and Allergic Fungal Rhinosinusitis (AFRS). The invasive type also has three subtypes: Acute Invasive Rhinosinusitis (AIRS), Chronic Invasive Rhinosinusitis (CIRS), and Granulomatous Invasive Sinusitis (GIFS). For a doctor to correctly identify these types, they have to consider many factors. These include the patient’s medical history and symptoms, imaging results, biopsies observed with a process known as histopathology, and lab tests.
For simplification, we group the infections into four types: Allergic Fungal Sinusitis, Fungal Ball, Invasive Fungal Sinusitis, and Granulomatous Sinusitis.
Another way to categorise these types is based on a patient’s immune system status. It’s generally understood that those with weakened immune systems are main targets of fungal sinusitis. Non-invasive types usually occur in patients with healthy immune systems, while invasive types mostly occur in those with weakened immune systems. Invasive types can become life-threatening if the infection spreads into the cranial space, leading to increased mortality and illness. Therefore, patients with weakened immune systems should take extra precautions and seek prompt treatment if fungal sinusitis is suspected.
What Causes Fungal Sinusitis?
The reasons behind fungal sinusitis aren’t completely clear, but we’re seeing more and more cases of it recently. This could be because people are using more immune-suppressing drugs and antibiotics, or it could be due to the rise in chronic diseases that weaken the immune system. Mucormycosis is one example – it’s a serious but rare disease that we mostly see in people with diabetes.
There are two main types of fungi that cause disease in humans: molds and yeasts. Fungal sinusitis is usually caused by molds. Molds are multicellular and have a structure called hyphae, while yeast is made up of single cells.
Humans are always around different types of fungi in the air, but usually, these fungi don’t harm our sinuses or cause other health problems. It’s also not uncommon for fungi to live in the sinuses without causing infection. Whether or not these airborne fungi end up causing sinus problems usually depends on the individual’s immune health. Things like diabetes, chemotherapy, the use of steroids, and generally weak immune systems can make people more prone to fungal sinus infections.
The fungi called Aspergillus is often the cause of allergic fungal sinusitis (AFS) and invasive fungal sinusitis (IFS). Other common causes of fungal sinusitis are the fungi Mucor and Rhizopus, which cause mucormycosis.
The most common type of fungal sinusitis is allergic fungal rhinosinusitis.
Risk Factors and Frequency for Fungal Sinusitis
The occurrence of fungal sinusitis, a type of sinus infection, varies depending on where in the world you live. For instance, granulomatous invasive sinusitis, which is typically a severe form of chronic fungal sinusitis, is most frequently seen in places like India, Sudan, and Pakistan. Different factors can contribute to the development of these infections as well. A study showed that physical injury was the main trigger for a specific type of fungal sinusitis known as mucormycosis in Asian countries, whereas in developed countries, having a weakened immune system was the prime cause.
Signs and Symptoms of Fungal Sinusitis
Invasive fungal sinusitis is a condition that medical professionals should be on alert for, especially in patients showing certain symptoms. These symptoms include congestion, headaches, dizziness, swelling of the eyes, skin infection around the eyes, balance disturbances, changes in personality or behavior, and repetitive vomiting. Certain patients may also experience deviation or bulging of the eyes. Most people with this condition have a fever and increased heart rate during the early stages of infection. Headaches are often the most common symptom in sphenoidal fungal sinusitis, making its diagnosis tricky due to its vague symptoms.
Pain is usually felt when pressure is applied to the facial sinuses, which include the maxillary, ethmoidal, sphenoid, and frontal sinuses. The maxillary sinus, in particular, is almost always affected in cases of fungal balls, making up about 94% of these cases. Due to the overlapping symptoms, this condition can often be mistaken for disorders related to ear, nose, and throat, neurological issues, or gut-related diseases, all of which warrant further investigation.
Saprophytic fungal sinusitis often does not show symptoms and can be difficult to detect. Invasive fungal sinusitis is more serious as it bypasses the mucosal barrier and involves nerves, blood vessels, and bone. Therefore, the symptoms are more obvious. These symptoms can include loss of sensation, cranial nerve dysfunction, headache and facial pain, discharge from the nose, and nasal casts.
- Congestion
- Headaches
- Dizziness
- Swelling of the eyes
- Skin infection around the eyes
- Balance disturbances
- Changes in personality or behavior
- Repetitive vomiting
- Deviation or bulging of the eyes
- Fever
- Increased heart rate
- Pain when pressure is applied to the facial sinuses
- Possibility of being misdiagnosed due to overlapping symptoms
- Loss of sensation, cranial nerve dysfunction, headache and facial pain, discharge from the nose, and nasal casts in more serious cases
Testing for Fungal Sinusitis
To diagnose fungal sinus infections, or fungal rhinosinusitis, doctors often use a procedure called functional endoscopic sinus surgery. After this procedure, they examine a sample of tissue under a microscope, a process known as histopathological analysis. Most often, they take the sample from an affected area in the nasal septum. If there is no visible affected tissue on the septum, they take the sample from the middle turbinate, which is part of the nasal passageway.
The collected sample is then cultured and mixed with an agent called KOH, which makes it possible to detect the presence of fungus under a microscope. One telltale sign of a specific type of fungal infection known as a fungus ball is the presence of a “cheesy and claylike” mucus during the endoscopic procedure. However, further examination of the tissue is needed to confirm the diagnosis.
Another approach used in diagnosing fungal sinusitis is polymerase chain reaction (PCR). Research has shown PCR to be highly accurate, making it particularly useful for ruling out the disease.
In invasive fungal sinusitis, a technique called frozen sectioning is used. This involves freezing the tissue removed from the infected sinuses, cutting it into small pieces, and staining it with substances for microscope examination. This technique can provide a quick diagnosis and can help detect the infection earlier, reducing the risk of death from the disease. In cases where it’s difficult to spot affected tissues under frozen sectioning, a stain called Periodic Acid Schiff (PAS) is used to improve visualization.
Touch preparation (TP) is another method of diagnosing invasive sinusitis. This method involves taking samples of tissue, placing them on a glass slide, and staining them for examination under a microscope. This method is particularly useful when only a small sample of tissue is available or there’s a heavy workload in the lab.
In addition, a type of imaging scan known as a computed tomography (CT) scan can be used to detect changes in the sinuses caused by fungal growth, such as thickened walls and abnormal areas of dense tissue or damage to the bones.
There are various types of fungal sinusitis. Each type has its own unique characteristics and is diagnosed using a combination of clinical findings, lab tests, and imaging studies. Regardless of the type, early and accurate diagnosis is crucial to guide treatment and improve the chances for a full recovery.
Treatment Options for Fungal Sinusitis
Surgical debridement, which is the removal of damaged tissue, is the usual treatment for most cases of fungal sinusitis. This procedure is both diagnostic, meaning it helps to confirm the problem, and therapeutic – it helps to resolve the problem. In certain cases, where complications arise before and during surgical debridements, a craniotomy, or a surgical opening in the skull, might be preferred. This is especially true if infections spread to a structure in your brain called the cavernous sinus.
A specific type of procedure known as functional endoscopic sinus surgery allows doctors to look closely at the disease and structure of the sinuses, take samples of the lesions for testing, clean out the sinuses, and fix any underlying issues such as a hole (fistula), or foreign body. On some occasions, doctors might also need to perform a polypectomy, which is the removal of polyps, or abnormal tissue growths.
Oral corticosteroids, a type of anti-inflammatory medicine, can help many acute and chronic fungal sinusitis symptoms by reducing inflammation and lowering the levels of a specific type of protein called Immunoglobulin E (IgE). However, using these drugs for a long time is not recommended. It is important to note that the plan for using corticosteroids should be personally tailored to each patient and based on their specific situation and needs. Nasal corticosteroids, which are applied directly into the nose, typically shouldn’t be used on their own, but can be helpful when used in combination with systemic steroids, which are taken orally. One study showed these drugs can help to reduce the chances of the disease returning after two years.
Systemic antifungals are medicines that work throughout your body to stop or slow the growth of the fungus. These drugs are not usually the best treatment option for AFS, but they can be used together with other treatments for invasive fungal sinusitis – a severe form of the disease. A drug called Amphotericin B might be the first choice to treat invasive disease, as it is effective against many different species of fungi, including Mucor and Aspergillus. Some other antifungal medications may also be beneficial. However, if these drugs are used, an infectious disease specialist should also be involved in patient management. Using antifungals locally, where they are applied directly into the nose, has only shown limited success and are generally not recommended.
Fungal immunotherapy, which helps the body build its immunity to fungal infections, is another possible treatment option for AFS. However, this treatment is expensive and has shown better short-term benefits than long-term benefits. One advantage is that it might reduce the need for corticosteroids and thus prevent the side effects of long-term use of these drugs.
Since most cases of invasive fungal sinusitis are caused by a weak immune system, it’s important to treat the cause of this immune deficiency in order to manage the disease effectively.
Another form of fungal sinusitis called Saprophytic fungal sinusitis doesn’t require surgery. This condition can be managed simply by cleaning the nasal sinuses, a process known as nasal douching, typically done with saline.
What else can Fungal Sinusitis be?
When diagnosing sinusitis, doctors consider various types that can cause the condition. These include:
- Bacterial sinusitis
- Viral sinusitis
- Allergic sinusitis
- Other kinds of sinusitis
What to expect with Fungal Sinusitis
The outlook for AFS (Allergic Fungal Sinusitis) is typically good, while it can be severe for IFS (Invasive Fungal Sinusitis), particularly if the patient’s immune system can’t be restored to normal function.
1) Allergic fungal sinusitis generally responds well to surgical treatment, and it’s possible to effectively manage any recurrence too. Follow-up is usually done with a functional endoscopy in a doctor’s office. Any additional needed treatments can be performed during this procedure. If cases aren’t treated, the disease can impact surrounding areas, but this is quite rare.
2) Invasive fungal sinusitis, on the other hand, is potentially life-threatening and has a poor outlook. This type of sinusitis can trigger complications such as a blood clot in the cavernous sinus (a large vein at the base of the brain) and infections in the central nervous system because it tends to spread. These complications are serious with around a 50% mortality rate, making immediate treatment crucial. Additionally, the disease can recur and often requires repeated treatments. Survivors may experience facial deformities, nerve damage, and chronic pain. The primary factor affecting the outlook for people with this disease is the condition of their immune system. A better outlook is possible if the immune system can be restored to normal function. However, if the immune system can’t be restored, the outlook is typically very bleak and can often be fatal.
3) Granulomatous sinusitis, inflammation of the sinuses due to granulomas (small areas of inflammation), can sometimes be a sign of systemic diseases like Wegener granulomatosis. The outlook for this kind of sinusitis mainly depends upon the treatment of the overarching disease.
Possible Complications When Diagnosed with Fungal Sinusitis
One serious but rare complication of severe sinus fungal infection is the spreading of the fungus to the cavernous sinus or the back part of the eye, known as the orbital apex. If the fungus spreads to both these areas, it’s referred to as cavernous sinus-orbital apex syndrome. Symptoms can include headaches, sudden loss of vision in one eye, or eye pain. These symptoms typically occur because of a blood clot in the cavernous sinus or a problem with the blood vessels connecting the cavernous sinus and the carotid artery (a major blood vessel in the neck). Though there have been many recent studies on sinus fungal infections, we still don’t understand it fully, making it difficult to diagnose and treat.
Common Symptoms:
- Headaches
- Sudden loss of vision in one eye
- Eye pain
Challenges:
- Understanding the disease
- Diagnosis
- Treatment