A 28-year-old man presents with severe sore throat, dysphagia, fever (39.5°C), and trismus for 3 days. Intraoral examination reveals unilateral bulging of the soft palate with deviation of the uvula to the opposite side. The tonsil appears enlarged and erythematous. Which investigation is most appropriate to confirm the diagnosis of peritonsillar abscess and guide drainage?

Explanation

## Diagnosis of Peritonsillar Abscess **Key Point:** Peritonsillar abscess (PTA) is a localized collection of pus between the tonsillar capsule and the superior pharyngeal constrictor muscle. While clinical diagnosis is often sufficient, imaging confirmation is essential before drainage. ### Role of Imaging in PTA **High-Yield:** Contrast-enhanced CT (CECT) of the neck is the gold standard for confirming peritonsillar abscess and differentiating it from severe tonsillitis. It provides: - Precise anatomical localization of the abscess - Assessment of abscess size and extent - Evaluation for complications (airway compromise, mediastinitis) - Guidance for drainage procedure (needle aspiration vs. incision and drainage) ### Clinical Presentation vs. Imaging Confirmation | Feature | Severe Tonsillitis | Peritonsillar Abscess | |---------|-------------------|----------------------| | Unilateral bulging | Absent | Present | | Uvula deviation | Absent/mild | Marked, away from lesion | | Trismus | Mild/absent | Marked | | Imaging finding | Edema only | Localized fluid collection | | Treatment | Antibiotics | Drainage + antibiotics | **Clinical Pearl:** The classic triad of PTA is: 1. **"Hot potato" voice** (muffled speech) 2. **Unilateral soft palate bulging** 3. **Uvula deviation to opposite side** These clinical signs strongly suggest PTA, but CECT confirms the diagnosis and rules out other complications (retropharyngeal abscess, epiglottitis). ### Why CECT is Superior to Other Imaging ```mermaid flowchart TD A[Clinical suspicion of PTA]:::outcome --> B{Imaging modality?}:::decision B -->|Ultrasound| C[Limited field of view<br/>Operator-dependent<br/>Poor for deep spaces]:::urgent B -->|CECT| D[Excellent soft tissue contrast<br/>Defines abscess boundaries<br/>Assesses complications<br/>Guides drainage]:::action B -->|Plain X-ray| E[No soft tissue detail<br/>Not useful]:::urgent D --> F[Proceed to drainage]:::action ``` **Tip:** In a resource-limited setting, clinical diagnosis + needle aspiration (showing pus) may suffice, but CECT is the standard of care in well-equipped centers. ### Intraoral Ultrasound While intraoral ultrasound can detect fluid collections, it has limited field of view and is operator-dependent. It is not the investigation of choice for initial diagnosis or pre-drainage assessment. [cite:Scott-Brown's Otolaryngology 8e Ch Pharyngitis and Tonsillitis]