Peritonsillar abscesses (PTAs) are the most common deep infection of the neck in both children and adults. PTAs often preceded by tonsilitis, pharyngitis, or cellulitis, but can occur without preceding infection.

• Diagnosis by history and physical exam alone, though needle aspiration or imaging.
• The majority of peritonsillar abscesses resolve completely with treatment, though life-threatening complications can occur if no intervention occurs.

History

• Systemic.
  • Fever.
  • Fatigue, malaise.
• Local.
  • Severe sore throat and otalgia (usually unilateral and preceded by tonsilitis or pharyngitis).
  • Decreased oral intake.
  • Voice muffling or “hot potato” voice.
• Risk factors.
  • Smoking.
  • Oropharyngeal infection or periodontal disease.
  • For spontaneous PTA – Weber gland obstruction.

Physical

• Trismus (reflexive spasm of the muscles of mastication) may prevent proper exam.
• Common findings.
  • Swollen and fluctuant tonsil, causing contralateral deviation of the uvula.
  • Fever.
  • Saliva pooling or drooling.
  • Cervical lymphadenopathy.
  • Swelling may extend into the soft palate, pharynx.

Investigations

Diagnosis can usually be made clinically, and investigations are only necessary if a physical exam is inconclusive.

• Laboratory
  • CBC and differential – elevated WBCs with predominance of PMNs.
  • Serum electrolytes if decreased nutritional or fluid intake.
  • Throat culture for group A streptococcus.
• Needle Aspiration
  • Confirmation of diagnosis if pus drained.
  • Therapeutic as all abscesses need drainage (I&D or aspiration).
  • Gram staining, culturing, and susceptibility testing of abscess fluid may be performed to optimize therapy, or in cases of recurrent infection.
• Imaging
• • Intra-oral or submandibular US preferred; may be used to differentiate between PTA and cellulitis.
  • Contrast-enhanced CT or MRI may be used to determine involvement of surrounding structures (i.e. retropharyngeal abscess).

Confirm patent airway. If intubation is necessary consult ENT and anesthesia; cricothyroidotomy may be considered

Antimicrobial Therapy

• Surgical management for majority of patients.
• If small abscess with no airway compromise, sepsis, trismus, or other complications present, patients may be admitted for a 24-hour trial of IV antimicrobial and supportive therapy.
• Empiric drug therapy should cover group A streptococcus, Staphyloccocus aureus, and respiratory anaerobes.

• •  Examples:
    • Penicillin G (10 million units q 6 hours) with metronidazole (500 mg q 6 hours).
    • Ceftriaxone (1 g q 12 hours) with metronidazole (500 mg q 6 hours).
    • IV ampicillin-sulbactam.
      • Children – 50mg/kg every 6 hours (max of 3 g per dose).
      • Adults – 3 g every 6 hours.
    • IV clindamycin.
      • Children – 13 mg/kg every 8 hours (max of 900 mg per dose).
      • Adults – 600 mg every 6-8 hours.
    • If no response to treatment, moderate to severe disease present, or high MRSA risk, add vancomycin (1 g q 12 hours – refer to local vancomycin guidelines).
    • Adjust therapy as required based upon culture and susceptibility testing.

• Transition to oral antimicrobial therapy can be made once clinical improvement and afebrile status are achieved (target total antibiotic course of 14 days).
  •  Examples:
    • Amoxicillin-clavulanate.
      • Children – 45 mg/kg per dose every 12 hours (maximum 875 mg per dose).
      • Adults – 875 mg every 12 hours.
    • Clindamycin.
      • Children – 10 mg/kg per dose every 8 hours (maximum 600 mg per dose).
      • Adults – 300-350 mg every 6 hours.
    • Linezolid (if MRSA suspected – see below for dosing) with metronidazole (500 mg q 6 hours).
      • Children (<12 years) – 30 mg/kg TID.
      • Children (≥12 years) – 20 mg/kg BID.
      • Adults – 600 mg BID.

Surgical Drainage

• Indications.
  • Complications from PTA (i.e. airway compromise, sepsis, trismus).
  • No response to antimicrobial therapy within 24 hours, if trialed.
• Surgical drainage by an otolaryngologist or experienced clinician.
  • Needle aspiration (see video).
  • Incision and drainage.
  • Tonsillectomy (only if recurrent or failure of other drainage techniques).
• Antimicrobial therapy post-surgery is recommended to clear remaining or disseminated infection.

Adjunctive Therapy

• IV fluid resuscitation if fluid depleted.
• Analgesia PRN.
• Corticosteroid options include:
  • Methylprednisolone 2-3 mg/kg IV or IM.
  • Dexamethasone 10 mg IV or IM or PO.

• Failure of outpatient management.
• Inability to take oral medications before or after surgical intervention.
• Severe sepsis.
• Dehydration.
• Airway compromise.
• Immunocompromised.
• Diabetes mellitus.

• Successful treatment is determined by symptomatic improvement within 24 hours of treatment.
• Ability to tolerate oral antibiotics, analgesics, and fluids.
• Advise patients to seek urgent re-evaluation if worsening symptoms, signs of systemic infection, hemorrhaging, or dyspnea.
• Monitoring with primary care physician should occur within 24-36 hours for outpatients, and within a week if admitted to hospital.

1. Peritonsillar Abscess.
   Hanna B, Qassem A, Ehrlich A. Nov 2, 2020. May 5, 2021.
   – DynaMed.

   
   

2. Peritonsillar Abscess.
   Galioto NJ.  2017;95(8):501-506.
   – American Family Physician Journal

   
   

3. Peritonsillar cellulitis and abscess.
   Wald ER.  Aug 12, 2019. May 5, 2021.
   – UpToDate.

   
   

4. Video: Ultrasound for Peritonsillar Abscess
   Technique and tonsil identification 4:42-8:05
   Drainage 8:06-10:26
   – YouTube