A 48-year-old woman with a 12-week history of nasal obstruction, thick nasal discharge, postnasal drip, and facial pressure is diagnosed with chronic rhinosinusitis (CRS) without nasal polyps. Nasal endoscopy shows mucopurulent discharge from the middle meatus. She has failed 4 weeks of topical nasal corticosteroid spray. What is the drug of choice for medical management at this stage?

Explanation

## Medical Management of Chronic Rhinosinusitis — Second-Line Therapy **Key Point:** When topical nasal corticosteroids (first-line) fail after 4 weeks, macrolide antibiotics (especially azithromycin) are the preferred second-line agent for chronic rhinosinusitis without nasal polyps. ### Why Macrolides in CRS? **High-Yield:** Macrolides (particularly azithromycin) have dual mechanisms in CRS: 1. **Antimicrobial effect** — covers atypical organisms (*Chlamydia*, *Mycoplasma*) implicated in CRS 2. **Immunomodulatory effect** — reduces mucosal inflammation, decreases mucus secretion, and modulates Th1/Th2 balance The anti-inflammatory action often persists even at sub-antimicrobial doses and is independent of bacterial eradication. ### Azithromycin Dosing in CRS | Parameter | Details | |-----------|----------| | **Dose** | 250 mg once daily or 500 mg three times weekly | | **Duration** | 8–12 weeks minimum (longer than acute infection) | | **Mechanism** | Biofilm disruption + macrophage modulation | | **Response time** | 4–8 weeks before clinical improvement | ### Treatment Algorithm for CRS ```mermaid flowchart TD A[Chronic Rhinosinusitis diagnosed]:::outcome --> B[Topical nasal corticosteroid spray]:::action B --> C{Response after 4 weeks?}:::decision C -->|Yes| D[Continue + saline irrigation]:::action C -->|No| E[Add oral macrolide azithromycin]:::action E --> F{Response after 8-12 weeks?}:::decision F -->|Yes| G[Continue maintenance therapy]:::action F -->|No| H[Consider FESS]:::action H --> I[Endoscopic sinus surgery]:::action ``` **Clinical Pearl:** Topical nasal corticosteroids (mometasone, fluticasone) are ALWAYS first-line for CRS. Oral antibiotics are added only after documented failure of topical therapy for ≥4 weeks. **Mnemonic:** **MAC-CRS** — *Macrolides, Anti-inflammatory, Chronic Rhinosinusitis* — captures the dual role of macrolides as both antimicrobials and immunomodulators. ### Why Not Systemic Corticosteroids? Oral corticosteroids (prednisolone) are NOT routine in CRS management because: - Short-term benefit only; rebound inflammation on withdrawal - Risk of systemic side effects (hyperglycaemia, osteoporosis, immunosuppression) - Reserved for acute exacerbations or CRS with nasal polyps (where they may provide temporary relief) **Warning:** Do not confuse CRS without polyps (managed with topical steroids + macrolides) with CRS with polyps (where systemic corticosteroids may be considered as adjunct). [cite:Park 26e Ch 4; EPOS 2020 Guidelines]