A 35-year-old man from Delhi presents with a 3-week history of purulent nasal discharge, facial pain over the cheeks, and fever. Nasal endoscopy shows pus in the middle meatus. CT PNS reveals opacification of the maxillary sinuses bilaterally with intact bony walls. He has already received 2 weeks of oral amoxicillin-clavulanate without improvement. What is the most appropriate next step in management?

Explanation

## Clinical Assessment This patient has **acute bacterial rhinosinusitis (ABRS)** with bilateral maxillary sinus involvement that has **failed first-line oral antibiotic therapy** (amoxicillin-clavulanate × 2 weeks). The CT shows opacification with **intact bony walls**, ruling out complications such as osteitis or orbital/intracranial extension. There is no mention of immunocompromise or severe systemic illness. ## Why Switching to a Fluoroquinolone Is the Correct Next Step **Key Point:** In uncomplicated ABRS that fails first-line beta-lactam therapy, the standard next step per ENT and infectious disease guidelines (AAO-HNS, IDSA) is to **switch to a second-line oral antibiotic with broader coverage** — typically a respiratory fluoroquinolone (levofloxacin or moxifloxacin) — before escalating to IV therapy or surgery. **High-Yield Rationale:** 1. **Amoxicillin-clavulanate failure** most commonly reflects beta-lactamase–producing *H. influenzae* or *M. catarrhalis*, or penicillin-resistant *S. pneumoniae* — organisms well covered by fluoroquinolones. 2. **Fluoroquinolones** (levofloxacin, moxifloxacin) achieve excellent sinus tissue penetration and cover the full spectrum of ABRS pathogens, including atypicals. 3. **FESS is not indicated** for uncomplicated ABRS failing one antibiotic course; surgery is reserved for recurrent/chronic sinusitis, complications, or failure of multiple medical regimens. 4. **IV antibiotics** are reserved for severe disease, orbital/intracranial complications, or immunocompromised patients — none of which apply here. 5. **Topical corticosteroids + saline** alone are adjuncts, not definitive therapy for active bacterial infection with purulent discharge. ## Management Algorithm for Failed ABRS | Scenario | Management | |----------|------------| | ABRS, first presentation | Oral amoxicillin-clavulanate × 10–14 days | | Failed first-line oral antibiotics (uncomplicated) | Switch to fluoroquinolone (levofloxacin/moxifloxacin) × 10–14 days | | Failed second-line oral antibiotics | Consider endoscopic culture ± IV antibiotics | | Complications (orbital, intracranial) or immunocompromised | IV antibiotics ± FESS | | Recurrent/chronic sinusitis refractory to medical therapy | FESS | **Clinical Pearl (KD Tripathi / Scott-Brown):** Respiratory fluoroquinolones are the preferred second-line agents for ABRS failing beta-lactam therapy due to their broad-spectrum activity, excellent bioavailability, and high sinus tissue concentrations. IV antibiotics and surgical intervention are reserved for complicated or refractory cases beyond second-line oral therapy. **High-Yield:** The intact bony walls on CT and absence of systemic complications make this an uncomplicated case — step-up to oral fluoroquinolone is appropriate before considering invasive options.