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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- CRS = >=12 weeks of symptoms plus objective inflammation on nasal endoscopy or CT
- Core symptoms: nasal obstruction, nasal drainage, facial pressure, and reduced smell; at least 2 are typically required
- Differentiate CRS with nasal polyps from CRS without nasal polyps; asthma and aspirin-exacerbated respiratory disease are key associations
- First-line long-term management: saline irrigation and intranasal corticosteroids
- CT is used to confirm disease and guide surgery, but symptoms alone are insufficient for diagnosis
Overview
Chronic rhinosinusitis is a chronic inflammatory condition of the nasal cavity and paranasal sinuses lasting at least 12 weeks. Unlike acute sinusitis, CRS is usually inflammatory rather than a persistent bacterial infection. Diagnosis requires both compatible symptoms and objective evidence of mucosal inflammation on nasal endoscopy or CT. Phenotypes include CRS with nasal polyps and CRS without nasal polyps; allergic fungal rhinosinusitis, aspirin-exacerbated respiratory disease, immunodeficiency, and cystic fibrosis are important special contexts.
Epidemiology
CRS affects a substantial proportion of adults and contributes to impaired sleep, smell, work productivity, and quality of life. It is associated with asthma, allergic rhinitis, atopy, smoking, dental disease, immune dysfunction, and anatomic obstruction. Nasal polyposis is more common in patients with asthma and aspirin-exacerbated respiratory disease. Unilateral persistent symptoms, epistaxis, cranial neuropathy, or a visible unilateral mass should not be attributed to routine CRS without malignancy evaluation.
Clinical Features
Symptoms
Nasal obstruction or congestion lasting >=12 weeks
Anterior rhinorrhea or posterior nasal drainage
Facial pressure or fullness; pain alone is less specific
Hyposmia or anosmia, especially with nasal polyps
Cough, sleep disturbance, fatigue, or ear pressure
Unilateral obstruction, recurrent epistaxis, facial numbness, diplopia, or weight loss
Signs
Edematous nasal mucosa, mucopurulent drainage, or polyps on anterior rhinoscopy/endoscopy
Nasal polyps: pale, translucent, mobile masses; must distinguish from unilateral tumor
Mouth breathing, hyponasal voice, or allergic shiners may coexist
Cranial neuropathy, orbital signs, or hard palate changes are red flags
Dental disease or oroantral fistula may suggest odontogenic sinusitis
Investigations
First-line
History and nasal examinationSymptoms must last >=12 weeks; identify asthma, NSAID sensitivity, allergy, immune risk, dental symptoms, and unilateral red flags
Objective confirmationNasal endoscopy showing polyps, edema, or mucopurulence OR CT showing sinus mucosal disease is required
Second-line
CT sinuses without contrastConfirms extent of disease and anatomy; obtain if diagnosis uncertain, recurrent/complicated disease, or before surgery
Allergy evaluationConsider when symptoms are seasonal/perennial, refractory, or linked to allergen exposure
Immune workupQuantitative immunoglobulins and vaccine response testing if recurrent sinopulmonary infections
Specialist
ENT referralFailure of appropriate medical therapy, nasal polyps, unilateral disease, recurrent acute exacerbations, or surgical consideration
BiopsyUnilateral mass, bone destruction, epistaxis, cranial neuropathy, or suspicious lesions
Culture-directed therapyEndoscopic culture for acute exacerbations or refractory purulent disease
Management
AAO-HNS 2025 Adult Sinusitis Update1
Foundational therapy
- High-volume saline irrigation daily; improves symptoms and mucus clearance
- Intranasal corticosteroid spray or irrigations, especially in CRS with nasal polyps
- Treat coexisting allergic rhinitis with allergen avoidance, intranasal steroids, antihistamines, or immunotherapy when appropriate
2
Antibiotics and oral steroids
- Antibiotics are not routine long-term CRS therapy; use for acute bacterial exacerbation with purulence or culture guidance
- Short-course oral corticosteroids can improve symptoms in CRS with nasal polyps, but recurrence and adverse effects limit repeated use
- Avoid chronic systemic steroids unless specialist-directed
3
Nasal polyps and advanced therapy
- Assess asthma and aspirin sensitivity; aspirin-exacerbated respiratory disease requires coordinated care
- Biologics such as dupilumab, omalizumab, or mepolizumab may be considered for severe recurrent CRS with nasal polyps under specialist care
4
Surgery
- Functional endoscopic sinus surgery if persistent symptoms and objective disease despite maximal medical therapy
- Surgery improves drainage and topical medication delivery; ongoing medical therapy remains necessary after surgery
Complications
- Reduced smell and taste: Particularly with nasal polyps; may persist despite treatment
- Recurrent acute exacerbations: Episodes of bacterial infection superimposed on chronic inflammation
- Asthma worsening: Upper and lower airway inflammation often track together
- Orbital/intracranial complications: Rare in CRS but possible during acute exacerbations
- Missed malignancy: Unilateral symptoms or epistaxis require careful evaluation
USMLE Step 2 CK Exam Tips
- 1CRS diagnosis requires BOTH symptoms >=12 weeks AND objective evidence on endoscopy or CT
- 2Do not treat chronic sinus symptoms with repeated empiric antibiotics unless acute bacterial exacerbation is present
- 3First-line chronic treatment: saline irrigation + intranasal corticosteroids
- 4Nasal polyps + asthma + aspirin/NSAID sensitivity = aspirin-exacerbated respiratory disease
- 5Unilateral nasal obstruction with epistaxis or cranial neuropathy = think tumor, not routine CRS
- 6CT sinuses is the imaging test used to confirm CRS and plan surgery
- 7Functional endoscopic sinus surgery is for refractory objective disease after medical therapy
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