What is the evaluation and treatment approach for chronic sinusitis?

Evaluation of Chronic Sinusitis

Chronic sinusitis requires confirmation with both clinical criteria (symptoms ≥8-12 weeks) and objective imaging, followed by systematic evaluation for underlying causes including allergy, immunodeficiency, and anatomic abnormalities. 1

Diagnostic Criteria

Clinical diagnosis requires at least 2 of 4 cardinal symptoms persisting ≥12 weeks: facial pain/pressure, hyposmia/anosmia, nasal drainage, and nasal obstruction. 2

Objective Confirmation Required

• Coronal CT scan with cuts through the ostiomeatal complex is the imaging gold standard for chronic sinusitis, showing extent and specific locations of disease. 1
• Perform CT imaging >4 weeks after acute bacterial sinusitis and after medical management to accurately assess chronic disease. 1
• Anterior rhinoscopy or nasal endoscopy should visualize the ostiomeatal complex for hyperemic/edematous turbinates and purulent discharge from the middle meatus. 1
• Standard sinus radiographs have limited utility; CT is far superior for evaluating the ostiomeatal complex and posterior sinuses. 1

Common pitfall: Imaging during or immediately after acute infection will overestimate disease extent. 1

Systematic Evaluation for Underlying Causes

Allergic Evaluation

• Test for IgE sensitization to inhalant allergens in all patients with chronic/recurrent sinusitis, as allergic rhinitis is a major predisposing factor. 1
• Nasal cytology demonstrates cellular inflammation patterns (eosinophils suggest allergic or non-allergic eosinophilic rhinitis; neutrophils suggest infection). 1
• Differentiate allergic rhinitis from vasomotor rhinitis, NARES (nonallergic rhinitis-eosinophilia syndrome), and rhinitis medicamentosa, as each requires different management. 1

Immunodeficiency Screening

Refer to allergist-immunologist for immunologic evaluation when chronic sinusitis is associated with: 1

• Recurrent otitis media, bronchitis, bronchiectasis, or pneumonia
• Failure of prior surgical procedures
• Unusually severe or refractory disease

Laboratory evaluation should include: 1

• Quantitative immunoglobulins (IgG, IgA, IgM)
• Specific antibody responses to tetanus toxoid and pneumococcal polysaccharide vaccine
• 3-10% of patients with therapy-refractory chronic sinusitis have humoral immunodeficiency (common variable immunodeficiency or selective IgA deficiency). 1

Anatomic Assessment

Evaluate for structural abnormalities that obstruct sinus drainage: 1

• Nasal septal deviation compressing the middle turbinate into the ostiomeatal complex
• Middle turbinate deformity or accessory structures blocking sinus outflow
• Obstructing nasal polyps (presence indicates need for otolaryngology referral after trial of oral corticosteroids)
• CT with extra cuts through the ostiomeatal complex clarifies anatomic obstruction. 1

Special Diagnostic Considerations

Consider nasal-sinus biopsy when suspecting: 1

• Neoplasia (especially with unilateral polypoid disease)
• Fungal disease (fungus balls, allergic fungal sinusitis)
• Granulomatous disease
• Ciliary dysfunction (tracheal biopsy for ultrastructural analysis)

Consider cystic fibrosis testing in young patients with chronic sinusitis or children with nasal polyps, as virtually all CF patients develop sinusitis. 1

Microbiologic Evaluation

Direct sinus aspiration or endoscopic culture is the only reliable method for determining microbial etiology; nasal vestibule or nasopharyngeal cultures are unreliable due to contamination. 1

• Maxillary sinus access: intranasal puncture below inferior turbinate
• Quantitative cultures ≥10³ cfu/mL distinguish true infection from colonization. 1
• In chronic sinusitis, culture diseased mucosa obtained during endoscopic sinoscopy or surgery, correlating with histopathology. 1

Important distinction: Chronic hyperplastic eosinophilic rhinosinusitis shows predominant eosinophils and mononuclear cells with few neutrophils—this does NOT respond to antibiotics and may require systemic corticosteroids. 1

Advanced Imaging Indications

MRI with contrast (request coronal views) is indicated for: 1

• Skull base dehiscence with opacification
• Unilateral sinonasal opacification on CT
• Sinonasal process with cranial extension
• Expansile sinonasal mass with bony erosion
• Sinonasal mass with orbital extension
• Suspected fungal sinusitis (very low T2 signal with fungal concretions)

CT with contrast is indicated for: 1

• Complications of sinusitis (periorbital edema, subperiosteal abscess)
• Suspected sinonasal tumor

Mandatory Specialist Referral Criteria

Refer to allergist-immunologist when: 1

• Condition persists several months or recurs 2-3 times/year despite primary care treatment
• Complications present (otitis, asthma, bronchiectasis, nasal polyps, bronchitis)
• Need to assess allergic/immunologic basis or immunocompetence
• Quality of life significantly affected with chronic school/work loss

Refer to otolaryngologist when: 1

• Anatomic abnormalities obstruct drainage
• Nasal polyps persist after appropriate medical therapy including oral corticosteroids
• Radiographic evidence of ostiomeatal obstruction despite aggressive medical management
• Consideration for functional endoscopic sinus surgery

Common pitfall: Premature surgical referral before maximizing medical treatment for underlying rhinitis. 1