Peritonsillar Abscess
I. The "On-Call" Snapshot
Clinical Significance in Malaysia: This is the most common deep neck infection you will encounter in the ED and on the ENT ward. Mismanaging it can lead to airway obstruction and sepsis, so it's a "can't miss" diagnosis.
High-Yield Definition: A paratonsillar abscess (PTA) or "quinsy" is a collection of pus that forms in the potential space between the tonsillar capsule and the superior constrictor muscle of the pharynx.
Clinical One-Liner: Basically, it's a complication of tonsillitis where the infection has spread behind the tonsil, forming a painful, pus-filled pocket that pushes everything to the other side.
II. Etiology & Risk Factors
Etiology: It's a polymicrobial infection. Think of a mix of aerobes and anaerobes. The most common players are Group A Streptococcus (Streptococcus pyogenes), but also Staphylococcus aureus, Haemophilus influenzae, and anaerobes like Fusobacterium necrophorum. It usually starts as an acute tonsillitis that progresses to cellulitis and then suppuration.
Risk Factors:
Modifiable:
Smoking (very common association)
Poor dental hygiene
Inadequately treated tonsillitis
Non-Modifiable:
Age (most common in young adults, 20-40 years old)
Chronic tonsillitis
III. Quick Pathophysiology
Simple terms: an infection in the tonsil gets bad enough to break through its capsule. It then spreads into the loose connective tissue of the peritonsillar space. An inflammatory response causes cellulitis (a phlegmon), and eventually, the body walls this off with a fibrous capsule, creating a pus-filled abscess. This abscess creates a mass effect, pushing the tonsil and soft palate medially and causing the classic clinical signs.
IV. Clinical Assessment
Red Flags & Immediate Actions:
Stridor or Respiratory Distress: Suspect airway compromise. Action: Alert your senior/ENT registrar immediately, keep the patient sitting up, apply high-flow oxygen, get the difficult airway trolley, and prepare for potential intubation in the OT.
Neck Stiffness or Torticollis: Suggests spread to the parapharyngeal or retropharyngeal space. Action: Alert senior, keep neck immobilised if there's concern, and anticipate urgent imaging (CT neck).
Sepsis (Hypotension, Tachycardia, Altered Mental Status): Action: Alert senior, secure two large-bore IV cannulas, take blood cultures, start fluid resuscitation, and commence IV antibiotics as per guideline.
History:
Common (>50%): Severe, unilateral sore throat; fever; odynophagia (pain on swallowing) leading to drooling; malaise.
Less Common (10-50%): Muffled "hot potato" voice; trismus (difficulty opening the mouth due to pterygoid muscle spasm); ipsilateral otalgia (referred pain to the ear).
Pertinent Negatives: Ask about previous episodes of tonsillitis, smoking history, and recent antibiotic use. The absence of trismus or uvular deviation doesn't rule it out, it might just be early-stage cellulitis.
Physical Examination:
General: Patient looks unwell, febrile, and dehydrated. May be drooling and speaking with a muffled voice.
Oropharynx: This is key. Look for a unilateral swelling of the soft palate and anterior tonsillar pillar. The tonsil on the affected side is pushed medially and inferiorly. The uvula will be deviated to the contralateral (unaffected) side. There might be tonsillar exudates.
Neck: Check for tender cervical lymphadenopathy, especially at the jugulodigastric node (level II).
Clinical Pearl: Don't just rely on looking. If the patient can tolerate it, gentle palpation of the swollen soft palate can reveal fluctuance, which strongly suggests an abscess over cellulitis. But be gentle, it's very painful.
V. Diagnostic Workflow
Differential Diagnosis:
Peritonsillar Cellulitis (Phlegmon):
Points For: Similar presentation (sore throat, fever, swelling) but often less severe trismus.
Points Against: No pus collection.
How to Differentiate: Needle aspiration is both diagnostic and therapeutic. If you aspirate and get no pus, it's cellulitis. You can treat this with IV antibiotics alone.
Infectious Mononucleosis (EBV):
Points For: Severe exudative tonsillitis, fever, malaise, cervical lymphadenopathy.
Points Against: Usually bilateral tonsillar swelling, posterior cervical nodes more prominent, may have splenomegaly.
How to Differentiate: Monospot test or EBV serology. Be aware, EBV can be complicated by a secondary bacterial PTA.
Dental Abscess:
Points For: Trismus, facial swelling, neck pain.
Points Against: Usually a clear odontogenic source on examination (e.g., a decayed molar). The swelling is often centered lower down in the buccal or submandibular space.
How to Differentiate: Dental examination and a dental panoramic radiograph (OPG).
Retropharyngeal/Parapharyngeal Abscess:
Points For: Severe throat pain, fever, neck stiffness.
Points Against: Swelling may be visible on the posterior pharyngeal wall, or present as a diffuse neck swelling rather than a focal palatal bulge.
How to Differentiate: A contrast-enhanced CT (CECT) of the neck is the investigation of choice.
Investigations Plan:
Bedside / Initial (First 15 Mins): The diagnosis is primarily clinical.
First-Line Labs:
FBC: To look for leukocytosis.
Urea & Electrolytes (U&E): Crucial to assess for dehydration from poor oral intake.
C-Reactive Protein (CRP): Will be elevated, useful as a baseline to monitor response to treatment.
Blood C&S: If the patient is septic.
Confirmatory / Gold Standard:
Needle Aspiration: This is the gold standard. Use a large gauge needle (18G or 20G) on a 10ml syringe. Aspirate at the point of maximal fluctuance, usually in the superior pole of the tonsil. Send any aspirated pus for culture and sensitivity (C&S).
CECT Neck: Not needed for uncomplicated PTA. Reserve it for when you suspect complications or deep neck space extension, or if the diagnosis is uncertain.
VI. Staging & Severity Assessment
There's no formal staging system like in oncology. We assess severity based on clinical features:
Uncomplicated PTA: Classic presentation with trismus, uvular deviation, but patient is stable, hydrated, and has a patent airway. Can often be managed as an outpatient after drainage.
Complicated PTA: Presence of any red flags:
Airway compromise (stridor)
Sepsis or systemic toxicity
Severe dehydration requiring IV rehydration
Suspicion of spread to adjacent deep neck spaces
Impact on Management: Complicated PTA requires immediate hospital admission, urgent ENT review, IV antibiotics, and likely drainage in a more controlled setting like the operating theatre.
VII. Management Plan
Immediate Stabilisation (The ABCDE Plan):
Airway: Is it patent? If any doubt, call for senior help immediately.
Breathing: Administer high-flow oxygen if hypoxic or in distress.
Circulation: Secure IV access, give a fluid bolus (e.g., 500ml Normal Saline) if tachycardic or hypotensive.
Drugs:
Analgesia: This is critical. Start with IV Paracetamol 1g. Add in an NSAID like IV Ketorolac 30mg if no contraindications. Opioids may be needed but use with caution due to risk of respiratory depression.
Antibiotics: Give the first dose immediately. Refer to the National Antimicrobial Guideline.
Steroids: A single dose of IV Dexamethasone (e.g., 8-10mg) can significantly reduce swelling and pain. It is widely practised.
Expose/Examine: Full head and neck examination.
Definitive Treatment (The Ward Round Plan):
Drainage: The mainstay of treatment is to drain the pus.
Needle Aspiration: Most common, can be done in the ED or treatment room.
Incision & Drainage (I&D): For larger abscesses or if aspiration fails. A scalpel is used to make a small incision to allow pus to drain.
Antibiotics:
First-Line (IV): As per the Malaysian National Antimicrobial Guideline, the preferred regimen is:
IV Benzylpenicillin 2MU q6h PLUS IV Metronidazole 500mg q8h
Alternatively: IV Amoxicillin/Clavulanate (Augmentin) 1.2g q8h
For Penicillin Allergy: IV Clindamycin 600-900mg q8h
Switch to Oral: Once the patient is afebrile and can swallow, switch to an oral agent to complete a 10-14 day course. Good options are Oral Amoxicillin/Clavulanate or Oral Clindamycin.
Supportive Care: IV hydration, adequate analgesia, and encouraging oral fluids once able.
Long-Term & Discharge Plan:
Ensure patient completes the full course of antibiotics.
Advise on smoking cessation and good oral hygiene.
Follow-up in the ENT clinic in 1-2 weeks.
Counsel the patient that recurrent PTA (around 10-15%) is an indication for elective tonsillectomy ("hot" or quinsy tonsillectomy is rarely done now).
VIII. Complications
Immediate (first 24 hours):
Airway Obstruction: Management: Urgent intubation or surgical airway.
Aspiration Pneumonitis: If the abscess ruptures spontaneously. Management: Supportive, antibiotics.
Hemorrhage: From injury to nearby vessels during drainage. Management: Apply pressure, alert senior/vascular team.
Short-Term (days to weeks):
Spread of Infection: To parapharyngeal or retropharyngeal spaces. Management: Urgent CT scan and likely surgical drainage in OT.
Sepsis: Management: Fluid resuscitation, broad-spectrum antibiotics, supportive care in ICU if needed.
Long-Term:
Recurrence of Abscess: Management: Re-drainage and schedule for elective tonsillectomy.
Lemierre's Syndrome: Septic thrombophlebitis of the internal jugular vein, usually caused by Fusobacterium. Rare but fatal. Management: Long-term high-dose antibiotics, consider anticoagulation.
IX. Prognosis
Excellent if diagnosed and treated promptly. Most patients recover fully within a week. The main prognostic factors are the speed of diagnosis and drainage, the patient's immune status, and the presence of complications. Mortality is very rare and is almost always due to airway obstruction or septic complications from delayed treatment.
X. How to Present to Your Senior
Use the SBAR format. Be concise and direct.
"Dr., for review please. This is [Patient's Name] in ED Zone Merah, a [Age]-year-old [Gender] with no significant past medical history, presenting with a 3-day history of severe right-sided sore throat and fever.
On examination, he is febrile at 38.5°C, trismic, and has a muffled voice. There is a right-sided peritonsillar bulge with uvular deviation to the left.
My main differential is a right paratonsillar abscess.
I have secured IV access, sent off FBC and U&E, and given IV Paracetamol and a fluid bolus. I plan to give the first dose of IV Augmentin now. I would like your assistance/supervision for needle aspiration to confirm and drain."
XI. Summary & Further Reading
Top 3 Takeaways:
Suspect PTA in any patient with a severe unilateral sore throat, trismus, and a "hot potato" voice.
The diagnosis is clinical, but needle aspiration is both diagnostic (confirms pus) and therapeutic (drains it).
Management is threefold: Drain the pus, give antibiotics (covering aerobes and anaerobes), and provide supportive care (fluids and pain relief).
Key Resources:
Primary Malaysian Guideline: National Antimicrobial Guideline (2019, or latest edition available). Specifically, the section on Otorhinolaryngology Infections.
UpToDate: Search for "Peritonsillar abscess".
StatPearls: Search for "Peritonsillar Abscess".
