Fungal Sinusitis: Comprehensive Management Guide
Classification and Clinical Recognition
Fungal sinusitis presents in three distinct forms requiring fundamentally different treatment approaches: allergic fungal sinusitis (non-invasive), fungal ball/mycetoma (non-invasive), and invasive fungal sinusitis (acute, chronic, or granulomatous). 1, 2
The classification determines survival, with invasive forms carrying 50-80% mortality rates even with treatment, making rapid differentiation critical 1
Key Clinical Patterns to Recognize:
Non-Invasive Forms:
- Allergic fungal sinusitis: Caused by Bipolaris, Curvularia, Aspergillus, and Dreschlera species; presents with thick eosinophilic mucin and nasal polyposis 1, 2
- Fungal ball: Typically unilateral maxillary or sphenoid sinus involvement with dense fungal concretions 2, 3
Invasive Forms:
- Acute invasive fungal sinusitis: Rapid progression <4 weeks in immunocompromised patients (neutropenia, hematologic malignancies, poorly controlled diabetes, AIDS, transplant recipients, those on steroids/chemotherapy) 1, 4
- Presenting symptoms: fever, rhinorrhea, diplopia, facial pain, headache—often nonspecific 1, 4
- Critical endoscopic finding: Pale mucosa progressing to ulceration and necrosis 1
Diagnostic Approach
Imaging Strategy:
CT without contrast is the initial imaging modality of choice for all suspected fungal sinusitis. 1, 3
CT findings by type:
- Fungal ball: Hyperattenuation within involved sinus (though nonspecific) 1
- Invasive disease: Bone erosion, periantral fat infiltration, pterygopalatine fossa involvement, septal ulceration, orbital extension 1
- A 7-variable CT model (infiltration of periantral fat, pterygopalatine fossa, nasolacrimal duct/lacrimal sac, bone dehiscence, septal ulceration, orbital involvement) with any 2 positive findings demonstrates 88% sensitivity for invasive disease 1
MRI with and without IV contrast is superior for:
- Detecting orbital and intracranial complications (thrombosis, cavernous sinus involvement, infarction, hemorrhage) 1, 3
- Evaluating vascular complications (pseudoaneurysm, arterial thrombosis/dissection) from angioinvasive fungi 1
Definitive Diagnosis:
Biopsy with histopathological examination remains the gold standard, demonstrating invasive fungi in sinonasal mucosa, vessels, and bone for invasive forms. 1, 3
Treatment by Type
Fungal Ball (Mycetoma):
Surgical removal via simple antrostomy is the definitive treatment; antifungal medications are NOT indicated. 2, 3
- More extensive procedures (antrostomy combined with inferior meatal window) may be needed in select cases and result in better outcomes with no residual inflammation 2
- Recurrence rate: 3-4% with longer follow-up, necessitating surveillance 2, 3
Allergic Fungal Sinusitis:
Complete surgical exenteration with mucosal preservation is the primary treatment, followed by mandatory postoperative steroid therapy. 2
Surgical approach:
- Endoscopic sinus surgery to remove all allergic mucin and fungal debris 2, 5
- Preserve mucosa to allow normal function to resume 2
Medical management (essential postoperatively):
- Oral and nasal corticosteroids are mandatory to control the inflammatory process 2, 5
- Postoperative antifungal therapy role remains unproven, though anecdotal reports suggest potential benefit as adjunct 2
- Consider immunotherapy and antimicrobial agents for bacterial superinfection 5
Critical pitfall: Unilateral polypoid disease may mimic tumors (inverted papilloma); always biopsy 2
Invasive Fungal Sinusitis:
Invasive fungal sinusitis requires aggressive combined therapy: immediate surgical debridement PLUS systemic antifungal therapy PLUS reversal of immunosuppression. 2, 3, 4
Surgical Management:
Aggressive debridement of ALL necrotic sinonasal tissue is essential and non-negotiable. 2, 4
- Endoscopic approaches demonstrate superior survival (64%) compared to open procedures (54%) 2
- Complete removal of infected and necrotic tissue is critical 2
- Goals: diagnostic sampling and debridement 4
- Repeat debridement often necessary based on clinical response 4
Medical Management:
Systemic antifungal therapy is mandatory and must be initiated immediately. 2, 3, 4
First-line antifungal therapy:
- Liposomal amphotericin B is the recommended first-line empiric therapy 2, 4
- Voriconazole may be superior for Aspergillus species 2, 3, 6
- Newer azoles offer better bioavailability and less toxicity 2
- Continue treatment for at least 6 weeks after surgical intervention 3
Voriconazole dosing (for invasive aspergillosis): 6
- Loading dose: IV formulation on Day 1
- Maintenance: 200 mg oral every 12 hours (achieves exposure similar to 3 mg/kg IV)
- Continue IV for at least 7 days before switching to oral
- Administer at least 1 hour before or after meals 6
Reversal of Immunosuppression:
Equally or more important than surgery and antifungals is reversal of underlying immune suppression. 4
- Discontinue or reduce immunosuppressive medications when possible 4
- Optimize diabetic control 4
- Consider immune-stimulating therapies (though require additional study) 4
Critical Pitfall:
AVOID oral corticosteroids in invasive fungal disease due to additive immunosuppressive effects, EXCEPT when needed to reduce edema with orbital or cerebral involvement. 2
Prognostic Factors in Invasive Disease
Patient-specific mortality predictors: 2
- Best survival: Diabetic patients (50% survival) 2
- Worst survival: Aplastic anemia (20%), renal/hepatic failure (24%), neutropenia (29%) 2
- Hematologic malignancies: Hazard ratio 3.7 for mortality 2
- Recent chemotherapy: HR 2.3 2
- Bone marrow transplant: HR 2.5 2
Follow-up and Surveillance
Regular endoscopic examination is mandatory to detect early recurrence, particularly in invasive forms. 2, 3
- CT imaging for surveillance of extent and recurrence 3
- Histopathological examination essential for classification 3
- Continued smoking after surgery is associated with significantly worse long-term outcomes 2
Treatment Algorithm Summary
- Suspect fungal sinusitis in immunocompromised patients with sinusitis symptoms, unilateral disease, or treatment-refractory chronic sinusitis
- Obtain CT without contrast immediately
- Perform nasal endoscopy looking for pale/necrotic mucosa (invasive) vs. thick mucin (allergic)
- Biopsy for definitive diagnosis and fungal culture
- If invasive disease suspected: Start liposomal amphotericin B immediately, arrange urgent surgical debridement, reverse immunosuppression
- If fungal ball: Schedule surgical removal via antrostomy; no antifungals needed
- If allergic fungal sinusitis: Complete surgical exenteration followed by mandatory corticosteroid therapy