Overview
Peritonsillar Abscess (Quinsy)
Topic Overview
Summary
Peritonsillar abscess (PTA), also known as quinsy, is a collection of pus between the tonsillar capsule and the pharyngeal muscles. It is the most common deep neck infection and typically follows acute tonsillitis. Classic presentation is severe unilateral sore throat, trismus, "hot potato" voice, and uvula deviation. Treatment is needle aspiration or incision and drainage plus antibiotics. Untreated, it can cause airway obstruction and spread to deeper neck spaces.
Key Facts
- Location: Between tonsillar capsule and superior constrictor muscle
- Presentation: Unilateral sore throat, trismus, muffled voice, uvula deviation
- Examination: Asymmetric tonsillar bulge, deviation of uvula
- Treatment: Aspiration or I&D + IV antibiotics
- Complication: Airway obstruction, parapharyngeal spread
Clinical Pearls
Trismus in sore throat = think quinsy (abscess irritating pterygoid muscles)
"Hot potato" voice = muffled speech due to swelling
Uvula deviation AWAY from the affected side (pushed by swelling)
Why This Matters Clinically
PTA is common and treatable but can cause airway compromise and spread to deeper neck spaces if missed. Recognition and drainage are curative.
Visual Summary
Visual assets to be added:
- Peritonsillar anatomy diagram
- Clinical photo showing uvula deviation
- Needle aspiration technique
- PTA management algorithm
Epidemiology
Incidence
- 30 per 100,000/year
- Most common deep neck infection
- Peak age: 15-35 years
Demographics
- Young adults most common
- Rare in children under 5
- No significant sex difference
Risk Factors
| Factor | Notes |
|---|---|
| Acute tonsillitis | Usually follows tonsillar infection |
| Smoking | |
| Poor dental hygiene | |
| Immunocompromise | |
| Previous PTA | 10-15% recurrence |
Pathophysiology
Mechanism
- Acute tonsillitis → spread beyond tonsillar capsule
- Infection spreads to peritonsillar space
- Abscess forms between capsule and superior constrictor
- May spread to parapharyngeal, retropharyngeal spaces
Organisms
- Group A Streptococcus (most common)
- Staphylococcus aureus
- Anaerobes (Fusobacterium, Prevotella, Peptostreptococcus)
- Often polymicrobial
Weber's Glands
- Salivary glands in peritonsillar space
- May be primary site of infection (some cases occur without tonsillitis)
Clinical Presentation
Symptoms
Signs
Red Flags
| Finding | Significance |
|---|---|
| Stridor/respiratory distress | Airway compromise |
| Severe trismus | May indicate deep space spread |
| Bilateral swelling | Rare; consider other causes |
| Sepsis | Systemic spread |
Severe sore throat (usually unilateral)
Common presentation.
Difficulty swallowing (odynophagia)
Common presentation.
Difficulty opening mouth (trismus)
Common presentation.
Fever
Common presentation.
Ear pain (referred otalgia)
Common presentation.
Muffled "hot potato" voice
Common presentation.
Drooling
Common presentation.
Clinical Examination
General
- Unwell, febrile
- Drooling
- Cervical lymphadenopathy
Oral Examination
- Trismus (may limit view)
- Asymmetric tonsillar bulge
- Uvula deviation to contralateral side
- Erythema of soft palate
- Pus visible (sometimes)
Neck
- Tender lymphadenopathy
- Check for deep space infection signs
Investigations
Clinical Diagnosis
- Often clinical — examination is diagnostic
Blood Tests
| Test | Purpose |
|---|---|
| FBC | Raised WCC |
| CRP | Elevated |
| U&E | Dehydration |
Imaging
| Modality | Indication |
|---|---|
| CT neck with contrast | If diagnosis uncertain, deep space spread suspected, or abscess not draining |
| Ultrasound | Can confirm abscess (intra-oral) |
Microbiology
- Aspirate for culture (guides antibiotic therapy)
Classification & Staging
By Stage
- Peritonsillar cellulitis (no abscess yet)
- Peritonsillar abscess (pus collection)
By Severity
- Uncomplicated PTA
- Complicated (airway compromise, deep space spread)
Management
Immediate
- IV access
- Analgesia
- IV fluids (often dehydrated)
- IV antibiotics
Drainage — Essential
Needle Aspiration:
- First-line in many centres
- 18G needle, topical anaesthesia
- Aspirate pus from abscess
- May need repeat aspiration
Incision and Drainage:
- If aspiration fails or large abscess
- Done under local anaesthesia
- ENT procedure
Tonsillectomy ("Quinsy Tonsillectomy"):
- Hot (immediate) vs interval (6 weeks later)
- Consider if recurrent PTA
IV Antibiotics
| Regimen | Notes |
|---|---|
| Benzylpenicillin + metronidazole | Standard |
| Co-amoxiclav | Alternative |
| Clindamycin | If penicillin allergic |
Supportive Care
- IV fluids
- Analgesia (paracetamol, ibuprofen, opioids if needed)
- Steroids (may reduce inflammation — some evidence)
Discharge
- Once able to eat and drink
- Oral antibiotics to complete 7-10 days
- Follow-up for consideration of tonsillectomy
Complications
Local
- Airway obstruction
- Parapharyngeal abscess
- Retropharyngeal abscess
- Internal carotid artery erosion (rare)
- Aspiration of pus
Systemic
- Sepsis
- Lemierre syndrome (internal jugular vein thrombophlebitis)
- Mediastinitis
Recurrence
- 10-15% recurrence rate
- Tonsillectomy reduces recurrence
Prognosis & Outcomes
Prognosis
- Excellent with drainage and antibiotics
- Rare mortality (airway complications)
Recurrence
- 10-15% if tonsils retained
- Lower after tonsillectomy
Evidence & Guidelines
Key Guidelines
- ENT UK Clinical Guidelines
Key Evidence
- Needle aspiration is as effective as I&D for most cases
- Tonsillectomy reduces recurrence
Patient & Family Information
What is a Quinsy?
A quinsy (peritonsillar abscess) is a collection of pus next to the tonsil. It usually happens after a bad throat infection.
Symptoms
- Very sore throat on one side
- Difficulty swallowing
- Difficulty opening your mouth
- High temperature
- Muffled voice
Treatment
- Draining the pus (needle or small cut)
- Antibiotics
- Painkillers
What Happens Next?
- Most people recover fully
- You may be offered an operation to remove your tonsils to prevent it happening again
Resources
References
Key Studies
- Powell J, Wilson JA. An evidence-based review of peritonsillar abscess. Clin Otolaryngol. 2012;37(2):136-145. PMID: 22321140
Reviews
- Galioto NJ. Peritonsillar abscess. Am Fam Physician. 2017;95(8):501-506. PMID: 28409593
- Klug TE, et al. Peritonsillar abscess: complication of acute tonsillitis or Weber's glands infection? Otolaryngol Head Neck Surg. 2016;155(2):199-207. PMID: 27143715