A 28-year-old man presents to the ENT clinic with a 5-day history of severe sore throat, dysphagia, and fever (39.2°C). On examination, the right tonsil is enlarged, erythematous, and covered with yellowish exudate. The uvula is deviated to the left. Intraoral palpation reveals a bulge in the soft palate above the tonsil. The patient has trismus (mouth opening ~2 cm). What is the most likely diagnosis?

## Clinical Diagnosis: Peritonsillar Abscess ### Key Diagnostic Features **Key Point:** A peritonsillar abscess (PTA) is a collection of pus in the space between the tonsillar capsule and the pharyngeal constrictor muscle, typically occurring as a complication of acute tonsillitis. ### Distinguishing Clinical Signs | Feature | Acute Tonsillitis | Peritonsillar Abscess | |---------|-------------------|----------------------| | **Onset** | Acute (1–3 days) | Progressive (4–7 days after tonsillitis) | | **Dysphagia** | Mild to moderate | Severe; may refuse liquids | | **Trismus** | Absent or mild | Marked (often <2 cm mouth opening) | | **Uvula deviation** | Midline or minimal | Deviated away from affected side | | **Soft palate bulge** | Absent | Present (bulge above tonsil) | | **Palpation** | Firm tonsil | Fluctuant bulge in soft palate | | **Fever** | Present | Present, often persistent | | **Response to antibiotics** | Improves within 48–72 hrs | No improvement; requires drainage | **High-Yield:** The **uvula deviation away from the affected side** and **intraoral bulge in the soft palate** are pathognomonic for PTA. Trismus is a hallmark sign due to involvement of the medial pterygoid muscle. ### Pathophysiology 1. Acute bacterial tonsillitis (usually Group A Streptococcus) 2. Spread to peritonsillar space (between tonsillar capsule and pharyngeal constrictor) 3. Localized suppuration and abscess formation 4. Mechanical effects: uvula deviation, soft palate bulge, trismus ### Clinical Pearl **Clinical Pearl:** The "hot potato voice" (thick, muffled voice) and severe dysphagia with drooling are classic presentations of PTA. Patients often cannot tolerate oral intake and appear toxic. ### Management Approach ```mermaid flowchart TD A[Suspected Peritonsillar Abscess]:::outcome --> B{Clinical diagnosis clear?}:::decision B -->|Yes| C[Intraoral drainage under LA]:::action B -->|No| D[Imaging: CT or Ultrasound]:::action D --> E{Abscess confirmed?}:::decision E -->|Yes| C E -->|No| F[Treat as acute tonsillitis]:::action C --> G[Send pus for culture]:::action G --> H[IV antibiotics: Amoxicillin-clavulanate or Cephalosporin]:::action H --> I[Supportive care + analgesia]:::action I --> J[Consider tonsillectomy after resolution]:::outcome ``` **Key Point:** Needle aspiration or incision and drainage under local anesthesia is the definitive treatment. Antibiotics alone are insufficient. [cite:Dhingra 7e Ch 9]