Evaluation of Chronic Sinusitis
Patients with chronic sinusitis (symptoms ≥8 weeks) require coronal sinus CT with extra cuts through the ostiomeatal complex as the primary diagnostic imaging study, combined with systematic evaluation for underlying inflammation, allergy, immunodeficiency, and anatomic abnormalities 1.
Diagnostic Criteria
Chronic rhinosinusitis is defined as symptoms persisting 8 weeks or longer, including nasal congestion, purulent discharge, facial pain/pressure, and reduced sense of smell 1. The diagnosis requires both clinical symptoms AND radiographic confirmation on CT or MRI 1.
Essential Evaluation Components
1. Imaging Studies
- Coronal sinus CT scan is the gold standard and mandatory for diagnosis 1
- Must include extra cuts through the ostiomeatal complex to clarify disease extent and specific locations
- CT provides the anatomic roadmap necessary if surgery becomes indicated
- Lund-McKay scoring system quantifies disease severity (scores 0-24) 2
- Do not use plain radiography - it lacks sufficient detail for chronic disease evaluation 3
2. Nasal Endoscopy (Optional but Valuable)
- Direct visualization of nasal cavity and sinus drainage pathways 1, 4
- Identifies polyps, anatomic variations, purulent discharge, and mucosal inflammation
- Sensitivity of 87.1% with 93.1% positive predictive value 5
- Lund-Kennedy endoscopic scoring documents polyps, edema, discharge, scarring, and crusting 2
3. Allergy Evaluation
Evaluate for IgE sensitization to inhalant allergens in all patients with suspected allergic rhinitis contributing to chronic sinusitis 1. This directly impacts treatment strategy with environmental control, pharmacotherapy, and potential immunotherapy 1.
4. Immunodeficiency Assessment
Refer to allergist-immunologist when chronic sinusitis occurs with 1:
- Recurrent otitis media, bronchitis, bronchiectasis, or pneumonia
- Persistent symptoms despite prior surgical procedures
- Unusually severe or refractory disease
Laboratory evaluation includes:
- Quantitative serum IgG, IgA, and IgM levels
- Specific antibody responses to protein antigens (tetanus toxoid)
- Specific antibody responses to polysaccharide antigens (pneumococcal vaccine)
5. Specialized Testing When Indicated
Consider nasal-sinus biopsy for suspected 1:
- Neoplasia
- Fungal disease (especially allergic fungal sinusitis)
- Granulomatous disease
- Ciliary dyskinesia (tracheal biopsy for ciliary structure/function evaluation)
Critical Distinction: Infectious vs. Non-Infectious Disease
Recognize chronic hyperplastic eosinophilic rhinosinusitis - a non-infectious form marked by eosinophils and mononuclear cells with few neutrophils 1. This does NOT respond to antibiotics and may require systemic corticosteroids instead.
Anatomic Abnormalities to Identify
Evaluate for structural problems requiring otolaryngology consultation 1:
- Nasal septal deviation compressing middle turbinate into ostiomeatal complex
- Middle turbinate deformity obstructing sinus outflow
- Accessory structures blocking sinus drainage
- Obstructing nasal polyps (after appropriate medical trial including oral corticosteroids)
Comorbidity Assessment
Identify conditions that modify management 6, 4:
- Asthma
- Cystic fibrosis
- Aspirin-exacerbated respiratory disease (AERD)
- Immunocompromised state
- Ciliary dyskinesia
Common Pitfalls to Avoid
Do not diagnose chronic sinusitis on symptoms alone - radiographic confirmation is mandatory 1, 7. Most symptoms (except dysosmia and polyps) do not reliably distinguish between normal and diseased patients.
Do not order CT scans for acute sinusitis unless complications or alternative diagnoses are suspected 4. Reserve CT for chronic or recurrent disease.
Do not assume all chronic sinusitis is infectious - consider eosinophilic disease that requires corticosteroids rather than antibiotics 1.
Do not proceed to surgery without maximizing medical treatment for underlying rhinitis first 1.
Specialist Referral Indications
Allergist-immunologist consultation for 1:
- Underlying allergic factors requiring management
- Evaluation of unusual pathogens
- Immunodeficiency assessment
- Complex pharmacologic management needs
Otolaryngologist consultation for 1:
- Structural abnormalities identified on imaging
- Persistent symptoms with radiographic ostiomeatal obstruction despite aggressive medical management
- Obstructing nasal polyps after failed medical therapy
- Consideration for functional endoscopic sinus surgery
The evaluation is algorithmic: establish diagnosis with symptoms plus CT confirmation → identify underlying causes (allergy, immunodeficiency, anatomic) → distinguish infectious from eosinophilic disease → maximize medical therapy → consider surgery only for refractory cases with documented anatomic obstruction.