USMLE Prep - Medical Reference Library

Peritonsillar Abscess — Drainage, Antibiotics, and Airway Precautions

System: Otolaryngology • Reviewed: Sep 1, 2025 • Step 1Step 2Step 3

Synopsis:

Severe unilateral sore throat with trismus, muffled ‘hot potato’ voice, and uvular deviation. Secure airway if threatened, drain (needle aspiration/incision and drainage), and start antibiotics covering streptococci and oral anaerobes; steroids can reduce pain/edema.

Key Points

  • Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
  • Set objective targets and reassess frequently.
  • Plan definitive source control or disease‑specific therapy when indicated; document follow‑up and patient education.

Algorithm

  1. Assess airway; consult ENT if difficult airway or spread suspected.
  2. Perform needle aspiration or I&D with suction and local anesthesia; send culture if needed.
  3. Start IV antibiotics; transition to PO for 10–14 days when improved; arrange follow‑up.
  4. Educate on recurrence and tonsillectomy indications in recurrent cases.

Clinical Synopsis & Reasoning

Severe unilateral sore throat with trismus, muffled ‘hot potato’ voice, and uvular deviation. Secure airway if threatened, drain (needle aspiration/incision and drainage), and start antibiotics covering streptococci and oral anaerobes; steroids can reduce pain/edema.


Treatment Strategy & Disposition

Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced/procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.


Epidemiology / Risk Factors

  • Risk varies by comorbidity and precipitants; see citations for condition‑specific data.

Investigations

TestRole / RationaleTypical FindingsNotes
Clinical exam ± intraoral ultrasoundDiagnosisPeritonsillar collectionUltrasound aids localization
CT neck with contrast (selected)ExtentDeep neck spreadUse if uncertain/complications
Culture of aspirate (optional)Pathogen IDStrep pyogenes, anaerobesTailor therapy

Pharmacology

Medication/InterventionMechanismOnsetRole in TherapyLimitations
Ampicillin‑sulbactam 3 g IV q6h or Clindamycin 600–900 mg IV q8hAntibioticsHoursFirst‑linePO step‑down amox‑clav or clinda
Dexamethasone 10 mg IV/PO (single dose)Anti‑inflammatoryHoursSymptom reliefAdjunct
Analgesia and hydrationSupportiveImmediatePain control

Prognosis / Complications

  • Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.

Patient Education / Counseling

  • Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.

References

  1. AAO‑HNS guidance and ENT reviews on peritonsillar abscess — Link