A 28-year-old woman presents to the emergency department with severe sore throat, odynophagia, and fever (39.5°C) for 3 days. On examination, she has unilateral tonsillar enlargement with exudate, uvula deviation to the left, trismus, and a 'hot potato' voice. Intraoral palpation reveals a bulge in the soft palate above the tonsil. Her white cell count is 14,500/μL. What is the most likely diagnosis?

## Clinical Diagnosis: Peritonsillar Abscess ### Key Clinical Features **Key Point:** Peritonsillar abscess is a collection of pus in the peritonsillar space (between the tonsillar capsule and pharyngeal constrictor muscle), typically occurring as a complication of acute tonsillitis. ### Diagnostic Criteria Present in This Case | Feature | Finding | Significance | |---------|---------|---------------| | **Unilateral involvement** | Yes (left side) | Abscess is almost always unilateral | | **Uvula deviation** | Yes (to left, away from abscess) | Pathognomonic sign of lateral pharyngeal space involvement | | **Trismus** | Present | Indicates involvement of muscles of mastication | | **'Hot potato' voice** | Present | Characteristic muffled speech from intraoral swelling | | **Bulge in soft palate** | Palpable above tonsil | Direct evidence of fluctuant collection | | **Duration** | 3 days (post-tonsillitis) | Typical timeline: abscess develops after 3–5 days of untreated tonsillitis | ### Pathophysiology 1. Acute bacterial tonsillitis (usually Group A Streptococcus or anaerobes) 2. Infection spreads beyond tonsillar capsule into peritonsillar space 3. Localized pus collection with surrounding edema 4. Lateral displacement of tonsil and soft palate 5. Uvula pushed away from affected side ### Distinguishing Features from Acute Tonsillitis **High-Yield:** Acute tonsillitis is bilateral or symmetrical; peritonsillar abscess is **always unilateral**. Uvula deviation and trismus are red flags for abscess. ### Management Principles - **Imaging:** Intraoral ultrasound or CT neck (contrast-enhanced) to confirm diagnosis and rule out deeper space involvement - **Antibiotics:** Broad-spectrum (amoxicillin-clavulanate or clindamycin) covering anaerobes - **Drainage:** Needle aspiration or incision and drainage under local anesthesia - **Supportive care:** Analgesics, antipyretics, warm gargles - **Follow-up:** Interval tonsillectomy after acute infection resolves (to prevent recurrence) ### Clinical Pearl **Clinical Pearl:** The combination of uvula deviation + trismus + unilateral tonsillar bulge is virtually diagnostic of peritonsillar abscess. Do not delay drainage waiting for culture results. [cite:Scott-Brown's Otolaryngology 8e Ch 8]