Peritonsillar abscess must be distinguished from peritonsillar cellulitis (see Peritonsillar Abscess and Cellulitis Peritonsillar Abscess and Cellulitis Peritonsillar abscess and cellulitis are acute pharyngeal infections most common among adolescents and young adults. Symptoms are severe sore throat, trismus, "hot potato" voice, and uvular... read more ) and from Parapharyngeal Abscess Parapharyngeal Abscess A parapharyngeal abscess is a deep neck abscess. Symptoms include fever, sore throat, odynophagia, and swelling in the neck down to the hyoid bone. Diagnosis is by CT. Treatment is antibiotics... read more , a deep neck abscess. Cellulitis does not require drainage and a parapharyngeal abscess should be drained as an operative procedure.
Clinically apparent peritonsillar abscess: Incision and drainage or needle aspiration
Possible peritonsillar abscess: Needle aspiration for diagnosis and treatment
Poor patient cooperation
Uncertain diagnosis (for incision and drainage)
If the diagnosis is uncertain, needle aspiration can be done to confirm the presence of an abscess. Alternatives include CT scan or, for mildly ill patients, discharge on antibiotics with close follow-up.
Aspiration of blood
Puncture of the carotid artery
Incomplete drainage of the abscess
Drugs for IV analgesia and sedation
Local anesthetic (eg, 1% lidocaine with epinephrine), 25- and 20- to 22-gauge needles, and 5-mL syringe
Topical anesthetic spray (eg, 4% lidocaine)
Light source, preferably a head lamp
Frazier-tip or Yankauer suction catheter attached to wall suction
For aspiration, a 10-mL syringe with 18- or 20-gauge needle
For incision and drainage, a scalpel with a No. 11 or 15 blade
For incision and drainage, a tonsil clamp
Needle aspiration may miss the abscess cavity and result in misdiagnosis as peritonsillar cellulitis. Thus, if an abscess is still suspected (eg, based on clinical or imaging findings), some clinicians treat patients with IV antibiotics, corticosteroids, and close observation—sometimes in hospital—even if needle aspiration yields no pus.
The tonsils are located between the anterior and posterior pillars of the throat. The lateral wall of the tonsil is adjacent to the superior pharyngeal constrictor muscle.
A peritonsillar abscess is located between the tonsil capsule, the superior pharyngeal constrictor muscle, and the palatopharyngeus muscle. The abscess is not within the tonsil.
The internal carotid artery lies about 2.5 cm posterolateral to the tonsil.
Patient should sit upright with a support behind the head to prevent sudden backward movement.
Step-by-Step Description of Procedure
Consider whether IV analgesia is necessary (usually not if adequate explanation and local anesthesia are given). If needed, may give fentanyl 1 to 3 mcg/kg, titrated if necessary, a few minutes before the procedure.
Spray the topical anesthetic and wait several minutes for it to take effect.
Have an assistant retract the cheek laterally to improve visibility.
Push the tongue out of the way using a tongue depressor or finger.
Identify the most prominent part of the abscess.
Inject 2 to 3 mL of anesthetic (1% lidocaine with epinephrine) into the mucosa using a 25-gauge needle attached to the 5-mL syringe.
Some clinicians give a dose of IV corticosteroids (eg, dexamethasone 10 mg, methylprednisolone 60 mg) to decrease symptoms.
For needle aspiration
Use the 10-mL syringe with an 18- or 20-gauge needle
Apply continuous suction and direct the needle in the sagittal plane (anterior to posterior) and not to the side (laterally). This is important to avoid the carotid artery.
Aspirate the most prominent area first; it is usually the superior pole. If no pus is aspirated, aspirate the middle, then inferior pole. Do not aspirate the tonsil itself.
Typically 2 to 6 mL of pus is obtained. Send a sample for culture.
For incision and drainage
Warn the patient that pus will flow and must be spit out.
Use a scalpel with a No. 15 blade or a No. 11 with tape covering all but 0.5 to 1.0 cm of the blade.
Make an 0.5 cm incision in the anterior-to-posterior direction over the most prominent area, or the location where needle aspiration (if done) identified pus.
Use a suction catheter to remove pus and blood. Some bleeding is expected after incision.
Place a closed tonsil clamp into the incised opening and gently open it to break up any loculations.
Have the patient rinse and gargle with a saline or a dilute peroxide-saline solution.
Observe the patient for 1 hour for complications such as bleeding, and to ensure that the patient can tolerate fluids.
Discharge on oral antibiotics and warm saline rinses to follow up in 24 hours
Patients with excessive bleeding, aspiration, or who are unable to take oral antibiotics require prolonged observation or hospitalization.
Patients who have had multiple abscesses should usually have elective tonsillectomy after 4 to 6 weeks to prevent abscess recurrence.
Antibiotics should be continued for 10 days. Examples of appropriate empiric drugs are penicillin, 1st-generation cephalosporins, and clindamycin. Preferably, culture-directed antibiotics are then prescribed. If methicillin-resistant Staphylococcus aureus (MRSA) is a possibility, empiric antibiotics should be broadened to cover this.
Warnings and Common Errors
Oversedating the patient and risking aspiration
Injecting anesthetic directly into the abscess cavity (because this is painful)
Inserting the needle or scalpel blade too deeply (because this risks penetrating the carotid artery); if pus is not obtained at 1-cm depth, do not go deeper.
For needle aspiration, not ensuring that the needle is inserted in the sagittal plane (anterior to posterior). Do not insert the needle to the side (laterally) in the direction of the carotid artery.
Tips and Tricks
A head mirror provides light precisely on the visual axis but takes practice to master.
When anesthetic is injected at the correct depth, the mucosa should blanch due to epinephrine-induced vasoconstriction.
For needle aspiration, to limit depth of penetration, some clinicians cut off the distal 1 cm of the plastic needle sheath and replace it over the needle, thus leaving only 1 cm of needle protruding. Tape the sheath onto the syringe so it does not fall off and become aspirated.
Similarly for incision and drainage, some clinicians apply tape to all but the distal 0.5 to 1 cm of the scalpel blade as a depth guide.
If pus continues to drain from the needle puncture site, repeat aspiration or incision and drainage may be indicated.