Overview
Quinsy (Peritonsillar Abscess)
1. Clinical Overview
Summary
Quinsy, also known as Peritonsillar Abscess (PTA), is a Collection of Pus in the Peritonsillar Space, located between the tonsillar capsule and the superior pharyngeal constrictor muscle. It is the Most Common Deep Neck Space Infection and typically represents a complication of Acute Tonsillitis. Quinsy predominantly affects Adolescents and Young Adults and is characterised by Severe Unilateral Sore Throat, Trismus (Difficulty opening mouth), Uvular Deviation away from the affected side, "Hot Potato" Voice, and Odynophagia. The most common causative organisms are Group A Streptococcus (GAS) and Oral Anaerobes (Fusobacterium). Diagnosis is primarily clinical. Treatment involves Drainage (Needle Aspiration or Incision and Drainage) and Antibiotics. Airway compromise is a rare but serious complication requiring urgent management. [1,2,3]
Clinical Pearls
"Trismus + Unilateral Sore Throat + Uvular Deviation = Quinsy": Classic triad.
"Hot Potato Voice": Muffled, Thick voice due to oropharyngeal swelling.
"Drain the Pus": Needle aspiration or I&D is therapeutic. Antibiotics alone are often insufficient.
"Watch the Airway": Rare but potentially life-threatening. Admit if concerns.
2. Epidemiology
Demographics
| Factor | Notes |
|---|---|
| Incidence | ~30 per 100,000 per year. |
| Age | Peak 15-35 years. |
| Sex | Slight male predominance or equal. |
| Season | More common in winter/Spring (Correlates with tonsillitis season). |
Risk Factors
| Risk Factor | Notes |
|---|---|
| Acute Tonsillitis | Preceding or concurrent. |
| Recurrent Tonsillitis | |
| Dental Infection | Periodontal disease. |
| Smoking | |
| Immunocompromise | Diabetes. |
Microbiology
| Organism | Notes |
|---|---|
| Group A Streptococcus (Streptococcus pyogenes) | Most common single organism. |
| Fusobacterium necrophorum | Anaerobe. Associated with Lemierre's Syndrome. |
| Other Anaerobes | Prevotella, Peptostreptococcus. |
| Polymicrobial | Common. Mix of aerobes and anaerobes. |
| Staphylococcus aureus | Less common. |
3. Pathophysiology
Mechanism
- Acute Tonsillitis: Bacterial infection of tonsil.
- Spread Beyond Tonsil: Infection penetrates tonsillar capsule or spreads via Weber's glands (Minor salivary glands in supratonsillar fossa).
- Peritonsillar Cellulitis: Inflammation in peritonsillar space.
- Abscess Formation: Pus collection (Typically 3-5 days after onset of tonsillitis).
- Location: Usually at Superior Pole of tonsil, Between capsule and superior constrictor.
Anatomy
| Structure | Relevance |
|---|---|
| Peritonsillar Space | Potential space between tonsil capsule and pharyngeal constrictor. |
| Internal Carotid Artery | Lies 2-2.5 cm posterolateral to tonsil. Risk with deep incision. |
| Parapharyngeal Space | Contiguous. Infection can spread → Parapharyngeal abscess, Retropharyngeal abscess, Mediastinitis. |
4. Clinical Presentation
Symptoms
| Symptom | Notes |
|---|---|
| Severe Sore Throat | Unilateral (Or significantly worse on one side). |
| Odynophagia | Severe pain on swallowing. May refuse to swallow saliva (Drooling). |
| Trismus | Difficulty opening mouth. Due to pterygoid muscle spasm. |
| Fever | Often high. Rigors. |
| "Hot Potato" Voice | Muffled, Thick voice. |
| Referred Otalgia | Ear pain on affected side (IX/X nerve). |
| Dysphagia / Drooling | Unable to swallow. |
| Neck Pain / Stiffness | |
| Halitosis |
Examination Findings
| Finding | Notes |
|---|---|
| Trismus | Limited mouth opening. |
| Uvular Deviation | Deviated AWAY from affected side (Pushed by swelling). |
| Unilateral Tonsillar Swelling | Bulging soft palate and anterior pillar. |
| Tonsillar Exudate | May or may not be present. |
| Cervical Lymphadenopathy | Tender, Enlarged jugulodigastric nodes. |
| Drooling | In severe cases. |
| Febrile, Unwell | Toxic looking. |
Red Flags
| Red Flag | Concern |
|---|---|
| Stridor / Respiratory Distress | Airway compromise. |
| Rapidly Spreading Swelling | Parapharyngeal/Retropharyngeal spread. |
| Sepsis | |
| Neck Swelling / Induration | Deep space infection. |
| Neurological Signs | Internal carotid involvement (Rare). |
5. Investigations
Diagnosis is Primarily Clinical
- Based on history and examination.
- Imaging not routinely needed if typical presentation.
Investigations (When Indicated)
| Investigation | Notes |
|---|---|
| Bloods | FBC (Leucocytosis), CRP (Elevated), U&Es (Dehydration). |
| Blood Cultures | If septic. |
| Throat Swab / Pus Culture | From aspirate. Guides antibiotics. |
| CT Neck with Contrast | If diagnostic uncertainty, Concern for deeper space infection (Parapharyngeal, Retropharyngeal), Or poor response to treatment. Shows rim-enhancing collection. |
| Lateral Soft Tissue X-Ray Neck | Rarely used. May show widened prevertebral soft tissue (Retropharyngeal abscess). |
| Intraoral Ultrasound | Can differentiate abscess from cellulitis. Not widely available. |
6. Management
Management Algorithm
SUSPECTED QUINSY
(Unilateral sore throat, Trismus, Uvular deviation)
↓
ASSESS AIRWAY
- Is there stridor? Respiratory distress?
┌────────────────┴────────────────┐
AIRWAY COMPROMISED AIRWAY SAFE
(Rare)
↓ ↓
**URGENT ENT / ANAESTHETICS** ASSESS FOR ABSCESS
- Humidified oxygen - Is there fluctuant swelling?
- IV Steroids - Marked bulging of palate?
- Prepare for emergency
drainage / Intubation /
Tracheostomy
↓
ABSCESS PRESENT?
┌────────────────┴────────────────┐
ABSCESS (PTA) PERITONSILLAR CELLULITIS
(Bulging palate, Fluctuance, (Early, No pus collection)
Pus on aspiration)
↓ ↓
**DRAINAGE + ANTIBIOTICS** **ANTIBIOTICS + OBSERVATION**
(ENT procedure) (May progress to abscess)
↓
DRAINAGE OPTIONS
┌──────────────────────────────────────────────────────────┐
│ **NEEDLE ASPIRATION** (Most Common First-Line) │
│ - Topical local anaesthetic spray + Local infiltration │
│ - 18-20G needle on syringe │
│ - Aspirate at point of maximal swelling (Usually supra- │
│ tonsillar) │
│ - Pus confirms abscess. Send for culture. │
│ - May need repeat aspiration (10-15% recollect) │
│ │
│ **INCISION AND DRAINAGE (I&D)** │
│ - Scalpel incision over abscess │
│ - Blunt dissection to open loculations │
│ - Larger drainage. Lower re-collection rate. │
│ - More painful. Bleeding risk. │
│ │
│ **QUINSY TONSILLECTOMY (Abscess Tonsillectomy)** │
│ - Drainage + Tonsillectomy at same time │
│ - Definitive. Prevents recurrence. │
│ - More complex surgery. Higher bleeding risk. │
│ - Consider if: Recurrent quinsy, Recurrent tonsillitis │
│ history, Concern for malignancy. │
└──────────────────────────────────────────────────────────┘
↓
ANTIBIOTIC THERAPY
┌──────────────────────────────────────────────────────────┐
│ **IV ANTIBIOTICS (If Admitted / Severe)** │
│ - Benzylpenicillin 1.2g QDS + Metronidazole 500mg TDS │
│ - OR Co-Amoxiclav 1.2g TDS │
│ │
│ **ORAL ANTIBIOTICS (If Less Severe / Discharge)** │
│ - Phenoxymethylpenicillin 500mg QDS + Metronidazole │
│ 400mg TDS │
│ - OR Co-Amoxiclav 625mg TDS │
│ │
│ **Penicillin Allergy**: Clindamycin 300-450mg TDS │
│ │
│ **Duration**: 7-10 days. │
└──────────────────────────────────────────────────────────┘
↓
SUPPORTIVE CARE
- IV Fluids (Dehydration from poor oral intake)
- Analgesia (Paracetamol, NSAIDs, ± Weak opioid)
- Corticosteroids (Dexamethasone 8mg IV single dose –
Reduces swelling, Pain, Return to oral intake)
↓
FOLLOW-UP
- Consider Interval Tonsillectomy (6-8 weeks later)
if: Recurrent tonsillitis, Recurrent quinsy
- Recurrence rate ~10-15% without tonsillectomy
7. Complications
| Complication | Notes |
|---|---|
| Recurrent Quinsy | ~10-15%. Consider tonsillectomy. |
| Parapharyngeal Abscess | Spread to parapharyngeal space. More serious. |
| Retropharyngeal Abscess | Rare. Airway risk. |
| Lemierre's Syndrome | Septic thrombophlebitis of Internal Jugular Vein. Fusobacterium. Septic emboli to lungs. Rare but serious. |
| Airway Obstruction | Rare but life-threatening. |
| Mediastinitis | Spread to mediastinum via retropharyngeal space. High mortality. |
| Aspiration | From spontaneous rupture. Aspiration pneumonia. |
| Haemorrhage | From drainage procedure. |
8. Prognosis and Outcomes
| Factor | Notes |
|---|---|
| Response to Drainage | Excellent. Immediate pain relief. |
| Recurrence | ~10-15% without interval tonsillectomy. |
| Mortality | Very low with treatment. Higher if complications (Mediastinitis). |
9. Evidence and Guidelines
Key Guidelines
| Guideline | Notes |
|---|---|
| SIGN / NICE | Antibiotics covering streptococcus and anaerobes. Drainage. Consider tonsillectomy for recurrence. |
10. Patient and Layperson Explanation
What is Quinsy?
Quinsy (Also called Peritonsillar Abscess) is a collection of pus (Abscess) next to the tonsil. It usually develops as a complication of tonsillitis.
What are the symptoms?
- Severe sore throat, Usually worse on one side.
- Difficulty opening your mouth (Trismus).
- Muffled, Thick voice.
- Difficulty swallowing.
- High fever.
- Drooling.
How is it treated?
- Draining the Pus: A doctor will numb the area and use a needle or small cut to drain the abscess. This usually gives immediate relief.
- Antibiotics: To clear the infection.
- Pain Relief and Fluids: You may need a drip if you can't swallow.
Will I need my tonsils out?
You may be offered a tonsillectomy a few weeks later, Especially if you have had tonsillitis or quinsy before.
When should I seek help urgently?
- Difficulty breathing.
- Worsening swelling in throat or neck.
- Unable to swallow at all.
- Feeling very unwell.
11. References
Primary Sources
- 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: 27095051.
- Johnson RF, et al. The contemporary approach to diagnosis and management of peritonsillar abscess. Curr Opin Otolaryngol Head Neck Surg. 2005;13(3):157-160. PMID: 15908813.
- SIGN / NICE. Management of sore throat and indications for tonsillectomy. 2010.
12. Examination Focus
Common Exam Questions
- Classic Triad: "What are the classic findings of quinsy?"
- Answer: Unilateral Sore Throat + Trismus + Uvular Deviation (Away from affected side).
- Voice Change: "What term describes the voice in quinsy?"
- Answer: "Hot Potato" Voice (Muffled, Thick).
- Treatment: "What is the first-line treatment for quinsy?"
- Answer: Drainage (Needle Aspiration or Incision and Drainage) + Antibiotics.
- Serious Complication: "What is Lemierre's Syndrome?"
- Answer: Septic Thrombophlebitis of Internal Jugular Vein (Often Fusobacterium necrophorum). Septic emboli to lungs.
Viva Points
- Uvula Deviates Away from Abscess: Pushed by swelling.
- Trismus = Pterygoid Spasm: Inflammation near pterygoid muscles.
- Interval Tonsillectomy: 6-8 weeks later if recurrent.
- Internal Carotid ~2.5 cm Posterolateral: Be aware during I&D.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.