Invasive fungal is an infection that occurs in the sinuses after certain types of fungus are inhaled.
There are two primary types of invasive fungal sinus infections, acute and chronic.
The acute version of fungal sinusitis is more serious and primarily occurs in people whose immune systems have been compromised. Fungi usually feed on dead organic matter, but weakened immune defenses can allow fungi to begin eating tissue that is still alive.
As the fungus reproduces, it spreads rapidly into the blood vessels, eye area, and central nervous system with devastating results. Acute invasive fungal sinusitis is a rare condition with a high mortality rate.
Fungal infection of the sinuses can occur when fungal organisms are inhaled and deposited in the nasal passageways and paranasal sinuses, causing inflammation. The dark, moist environment of the sinuses is ideal for fungi, which can reproduce without light or food.
Most fungal infections of the sinuses are noninvasive, meaning they won’t spread to surrounding tissue.
Invasive Fungal Sinusitis
Invasive fungal sinusitis is rare and includes both rhinocerebral mucormycosis (Mucor, Absidia, and Rhizopus sp.) and other invasive fungal infections, such as Aspergillus. The fungus spreads rapidly through vascular channels and may be lethal if not detected early.
Patients with mucormycosis almost invariably have some degree of immunocompromise, such as diabetes mellitus, long-term corticosteroid therapy, or end-stage renal disease, and particularly profound immunocompromise such as for the treatment of hematologic malignancies. Occasional cases have been reported in patients with AIDS, though Aspergillus sp. is more common in this setting.
Signs and Symptoms
The initial symptoms may be similar to those of acute bacterial rhinosinusitis, although facial pain is often more severe. Nasal drainage is typically clear or straw-colored, rather than purulent, and visual symptoms may be noted at presentation in the absence of significant nasal findings. On examination, the classic finding of mucormycosis is a black eschar on the middle turbinate, but this finding is not universal and may not be apparent if the infection is deep or high within the nasal bones. Often the mucosa appears normal or simply pale and dry.
- Change in mental status
- Changes in vision
- Congestion and nasal discharge
- Facial pain, numbness and/or swelling
Symptoms of chronic invasive fungal sinusitis include:
- Congestion, drainage
- Facial pain and pressure, much like that of a long-standing sinus infection
Early diagnosis requires suspicion of the disease and nasal biopsy with silver stains, revealing broad nonseptate hyphae within tissues and necrosis with vascular occlusion.
Because CT or MRI may initially show only soft tissue changes, biopsy and ultimate debridement should be based on the clinical setting rather than radiographic demonstration of bony destruction or intracranial changes
Invasive fungal sinusitis represents a medical and surgical emergency. Once recognized, amphotericin B by intravenous infusion and prompt wide surgical debridement are indicated for patients with reversible immune deficiency (eg, poorly controlled hyperglycemia in diabetes).
Lipidbased amphotericin B (Ambisome) may be used in patients who have kidney disease or who develop it secondary to nephrotoxicity of nonlipid amphotericin.
Other antifungals, including voriconazole and caspofungin, may be appropriate therapy depending on the fungus. Surgical management, while necessary for any possibility of cure, often results in tremendous disfigurement and functional deficits (eg, often resulting in the loss of at least one eye). Even with early diagnosis and immediate appropriate intervention, the prognosis is guarded. In persons with diabetes, the mortality rate is about 20%.
If kidney disease is present or develops, mortality is over 50%; in the setting of AIDS or hematologic malignancy with neutropenia, mortality approaches 100%.
Whether to undertake aggressive surgical management should be considered carefully because many patients are gravely ill at the time of diagnosis, and overall disease-specific survival is only about 57%.