Fungal sinusitis refers to any inflammation or infection of the sinuses caused by fungi. Fungi are commonly found in our environment and in most instances, do not cause serious infections. Very few of the thousands of fungi have been found to cause infections in humans. There are 4 types of fungal sinusitis:
- Fungal Ball (Mycetoma)
- Chronic Invasive Sinusitis
- Acute Invasive Sinusitis
- Allergic Fungal Sinusitis
A fungal ball or mycetoma is an isolated fungal infection typically occurring in a single sinus cavity. Fungal balls are routinely found in the maxillary or sphenoid sinus. Patients present with recurrent infections, pain and chronic postnasal drip. Aspergillus is the most commonly found fungus. CT scans show characteristic findings of the fungal ball and little damage to surrounding bone. Treatment consists of endoscopic removal of the fungal ball.
[caption id="attachment_113" align="alignnone" width="221" caption="Electron micrograph of Aspergillus."]
Acute and Chronic Invasive Fungal Sinusitis
Fungal invasive sinusitis is a very serious sinus infection most commonly seen in poorly controlled diabetics and severely immunocompromised patients. Immunocompromised patients includes those patients in the advanced stages of AIDS and bone marrow transplant patients. Acute invasive fungal sinusitis is an aggressive infection that invades the nose, sinuses and surrounding tissues. The tissue dies and the infection spreads quickly. The mortality rate is high and approaches 100% if not treated early and aggressively. Fungi responsible for these severe infections include Rhizopus, Aspergillus and Mucor. Old terminology used the term Mucormycosis to describe these infections. Fortunately, these infections are rare.
Chronic invasive fungal sinusitis is similar to acute invasive fungal sinusitis except it is a much slower infection.
CT scans will show blockage of the sinuses, destruction of bone and possibly invasion into surrounding soft tissues, eye and possibly the brain. Patients require immediate surgery and anti-fungal medicines for the best chance of survival.
Allergic Fungal Sinusitis
Allergic Fungal Sinusitis is the most common type of chronic fungal sinus infection. This disorder was named by Dr. Frederick A. Kuhn in the 1990s. The fungi involved in the Dematiaceous family; Bipolaris, Curvularia and Alternaria. Other species are found in different parts of the country depending on patient exposure.
Patients present with nasal polyps (swelling of the nasal lining), allergies, and recurrent infections. Functional endoscopic sinus surgery is indicated to remove fungal irritants and open up the natural sinus drainage pathways. Recurrence rates are extremely high and patients often require long-term follow-up.
The treatment is somewhat controversial depending on which expert is involved, however we treat patients with surgery, allergy shots, anti-fungal medicines, irrigations, steroids and culture-directed antibiotics for recurrent infections. Immunotherapy (allergy shots) should be provided by a doctor trained in allergy treatment. We do not provide allergy treatment in our office but will refer you to allergists who are experts in the area.
The most current thinking is that allergic fungal sinusitis is an allergic response to fungi in the environment with formation of nasal polyps and recurrent infections. Dr. Kuhn describes the response as a genetic switch that has been activated when exposed to a specific fungus. Research is currently underway to understand the genetic response in this disease.
[caption id="attachment_115" align="alignnone" width="300" caption="This coronal CT scan demonstrates an isolated fungal ball in the right sphenoid sinus. The patient present with severe headaches at the back of the head and underwent endoscopic sinus surgery for complete removal and cure."]