Fungal sinusitis is a lot more common than it was once thought to be. While the symptoms of fungal sinusitis may mimic those of chronic sinusitis or allergic sinusitis, the treatment of fungal infections differs entirely. Also, invasive fungal sinusitis can result in serious complications if not diagnosed early and treated adequately.
Fungal Sinusitis – Opportunistic Infection
Fungi are plant-like organisms that thrive in warm and humid climates, which is why they easily colonize the sinuses which are dark, moist cavities in the skull bones. Fungal infections are usually opportunistic, meaning they occur when there is immunosuppression in the body or the defense mechanism of the body is lowered. This happens with diabetes, AIDS, overuse of antibiotics, use of immunosuppressive drugs to prevent graft rejection and some chronic diseases.
However, it is now known that fungal sinusitis can also affect the immunocompetent or healthy individual. Fungal infections occurring in people without any immune deficiency are usually benign and non-invasive while those affecting the immunosuppressed may be invasive. The most common organisms causing fungal sinusitis are Aspergillus and Mucor.
Types of Fungal Sinusitis
There are 4 types of fungal sinusitis:
- Allergic fungal sinusitis
- Fungal ball or mycetoma
- Acute fulminant fungal sinusitis
- Chronic invasive fungal sinusitis
The first two types occur in immunocompetent individuals. Allergic fungal sinusitis is an allergic or hypersensitivity reaction to fungal elements in the environment. The affected individual has nasal block and discharge and may develop nasal polyps, sometimes extensive.
Fungal ball or mycetoma is a condition where fungal colonies grow in the cavities of the sinuses and sometimes occupy them completely. They commonly grow in the maxillary or the sphenoid sinuses. These patients may experience nasal stuffiness and have other features of sinusitis like nasal blockage and discharge, usually one-sided. It may sometimes be an incidental finding in a CT scan.
The other two varieties are invasive and can spread to neighbouring structures like the eye and brain. While they usually occur in the immunocompromised, they have been reported even in immunocompetent individuals.
Acute fulminant fungal sinusitis is a rapidly spreading infection. The patient may experience fever, severe headache, facial pain, nasal obstruction and nasal discharge which may be blackish or blood stained. Endoscopy may show the nasal tissues turning black and necrotic. This condition can be rapidly fatal if not treated immediately. The infection may spread to the eye causing blindness and the brain resulting in meningitis.
Chronic invasive fungal sinusitis is similar but spreads more slowly giving rise to all the features of long standing chronic sinusitis with no response to antibiotic treatment. This infection may also spread to the eye but the acute and toxic symptoms of the acute fulminant variety are absent.
Diagnosis and Treatment of Fungal Sinusitis
Headache, facial pain, nasal obstruction and nasal discharge are the usual features of any type of sinusitis. Fungal sinusitis is suspected when the facial pain is severe and the discharge dark colored. It is also considered when the symptoms fail to respond to repeated doses of the usual antibiotic treatment aimed at bacteria.
The diagnosis is by CT scan, which has characteristic findings of opacification due to concretions, and microscopic and culture studies of the discharge.
For the noninvasive conditions, antifungal drugs play almost no role. The treatment consists of surgically removing the fungal ball, debris and polyps. Corticosteroid nasal sprays are effective in the treatment of allergic fungal sinusitis.
The invasive varieties require surgical debridement of the necrotic tissue along with intravenous or oral antifungal drugs and treatment of the underlying immune deficiency. Long term follow up may be necessary.
Sources:
Gleeson, Michael J. "Scott-Brown's Otorhinolaryngology: Head and Neck Surgery" (Oxford University Press; 7 edition, 2008)
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