Peritonsillar Abscess Drainage Procedures

The peritonsillar abscess (PTA) remains a common clinical entity in the emergency department and in an otolaryngology practice. The exact incidence has been estimated at 30 cases per 100,000 people per year.

PTA is rare in infants and children younger than 12 years. The mean age for this disease is 20-30 years; males and females are affected equally. PTA usually occurs near the superior pole of the palatine tonsil, in the space outside of the tonsillar capsule between the superior constrictor and the palatopharyngeus muscle. ^[1]

An untreated PTA can lead to numerous complications, including the following:

• Erosion of the carotid artery

• The development of sepsis

• The development of other localized serious bacterial infections, including mediastinitis and deep neck space infections, which arise from tracking of the infection from the tonsillar fossas to the deep fascial planes of the neck with extension into the chest

The most common treatments for PTAs include the following: ^{[2, 3]}

• Needle aspiration: Needle aspiration can be therapeutic in itself; in some studies, up to 85% of patients were effectively treated with outpatient needle aspiration and oral antibiotics. ^{[4, 5]} Aspiration can also be used to confirm the diagnosis and localize the PTA for incision and drainage.

• Incision and drainage: Success rates of the incision and drainage technique are reported in the literature as similar to or slightly higher than reported success rates of the needle aspiration technique.

• Quinsy tonsillectomy: Quinsy is an obsolete term for PTA. The quinsy tonsillectomy, then, is a tonsillectomy performed in the presence of a PTA. The different techniques of tonsillectomy are not discussed in this article. For information, see Otolaryngology article Tonsillectomy.

In one study, 60% of otolaryngologists in the United Kingdom used needle aspiration as the primary means of treating a peritonsillar abscess. If needle aspiration failed, 52% would then perform an incision and drainage. ^[6]

In another study of 20,546 weighted cases of PTA from 2000 to 2009 in children aged younger than 18 years, researchers found a significant increase in the rates of incison and drainage from 26.4% to 33.7% and a significant decrease in the rate of tonsillectomy from 13.0% to 7.8%. ^[7]

Microbiology of the peritonsillar abscess

See the list below:

• Several studies have looked at the bacteriology of PTA aspirates. A mixture of aerobic and anaerobic bacteria is commonly isolated. ^{[8, 9]} The most common aerobic bacteria are Streptococcus group A (GAS), beta-hemolytic streptococci group C and G, and Staphylococcus aureus.

• The most common anaerobic bacteria isolated from PTA aspirates is Fusobacterium necrophorum (FN). FN is a gram-negative, obligate anaerobic, pleomorphic rod. It is also the pathogen most commonly associated with Lemierre syndrome. ^{[10, 8]}

• In one study from Denmark, Fusobacterium was the most commonly isolated bacterium (23%), followed by group a streptococci (17%), and groups C and G streptococci (5% total for both groups). ^[10]

• Some controversy surrounds the need to obtain cultures after management of a PTA. ^[11] Gavriel et al did find that patients with anaerobic bacteria growth correlated with higher rates of recurrent PTAs, suggesting that the presence of anaerobic bacteria be a relative indication for tonsillectomy. ^[9]

Relevant Anatomy

The tonsils begin developing early in the third month of fetal life. They arise from the endoderm lining, the second pharyngeal pouch, and the mesoderm of the second pharyngeal membrane and adjacent regions of the first and second arches. The epithelium of the second pouch proliferates to form solid endodermal buds, growing into the underlying mesoderm; these buds give rise to tonsillar stroma. Central cells of the buds later die and slough, converting the solid buds into hollow tonsillar crypts, which are infiltrated by lymphoid tissue.

Both right and left tonsils form part of the circumpharyngeal lymphoid ring. The size of the tonsil varies according to the age, individuality, and pathologic status. At the fifth or sixth year of life, the tonsils rapidly increase in size, reaching their maximum size at puberty. At puberty, the tonsils measure 20-25 mm in vertical and 10-15 mm in transverse diameters.

For more information about the relevant anatomy, see Tonsil and Adenoid Anatomy.

Incision and drainage is indicated in cases of suspected peritonsillar abscess.

Absolute contraindications to the procedure include malignancy and vascular malformations. The procedure may also be contraindicated in a pediatric patient or a difficult or uncooperative patient.

Anesthesia is indicated (topical, local, or both). Such anesthesia can include combinations of the following:

• Cetacaine spray

• Viscous lidocaine

• Local injection of anesthesia ^[12]

For more information on topical anesthetics, see Topical Anesthesia. For more information on local anesthetics, see Infiltrative Administration of Local Anesthetic Agents.

Technique for anesthesia

See the list below:

• Spray the tonsil and ipsilateral soft palate with benzocaine (eg, Cetacaine) topical spray.

• Using an 18-gauge (ga) needle on a 10-mL syringe, draw up approximately 6-10 mL of lidocaine 1% with epinephrine.

• Change to a 27-ga needle (preferably a long needle).

• Inject the mucosa overlying the fluctuant area with local anesthetic.

  Injection of local anesthetic.

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Equipment necessary to perform the procedure includes the following:

• Anesthesia (benzocaine spray, lidocaine 1% with 1:100,000 epinephrine)

• Syringe, 10 mL

• Needles, 18 and 27 ga

• Scalpel (Blade should be only partially uncovered/uncapped to expose only the tip of the scalpel; this avoids a deep incision.)

• Tongue retractor (sweetheart retractor pictured below) or tongue depressor

• Long curved Kelly clamp (for blunt dissection after incision with scalpel)

• Gloves

• Oral suction

• Culture swabs, if indicated

• The image below depicts some of the equipment used for the incision and drainage of a PTA.

  Some equipment used for the incision and drainage of a PTA.

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The patient should be sitting upright in one of the following locations:

• At the edge of a gurney

• In an ENT examination chair

Preparation

See the list below:

• Explain the procedure, benefits, risks, and complications to the patient and/or the patient's representative and obtain a signed informed consent.

• Ask the patient and/or the patient's representative if they would like others to be present for the procedure.

• Ensure that adequate lighting is available.

• Ask the patient to assume the preferred upright seated position.

• An oral suction system should be available to prevent aspiration of abscess contents into the patient's airway. Turn the suction system on and test for adequate suction strength.

• Using direct visualization at all times, anesthetize the suspected area of the peritonsillar abscess. The anesthetics most commonly used are local anesthetics with or without benzocaine spray. (Benzocaine spray is sometimes used alone during the needle aspiration technique.)

Incision and drainage technique

With a guarded scalpel (only part of the blade is exposed, to prevent a deep incision from being made), make a small incision above the tonsil, in the soft palate. Medial and superior incisions are safer from the standpoint of potential injury to the carotid artery.

Using a curved Kelly clamp, enter the incision and perform gentle blunt dissection inferiorly, posteriorly, and slightly laterally. Gentle dissection in the area of fluctuance is usually sufficient to enter the abscess cavity. Once the abscess cavity is found, continue gentle dissection with the curved Kelly clamp to break up any loculations.

Needle aspiration technique

See the list below:

• Insert an 18-ga needle on a 10-mL syringe into the area of suspected PTA.

• Aspirate with the syringe while inserting it.

• If no abscess is found, slowly withdraw the needle and reinsert.

Postdrainage

See the list below:

• The aspirate or abscess contents can be sent to microbiology for gram stain and culture.

• Administer a single high dose of steroid, unless contraindicated. ^[13] One option is a single dose of Dexamethasone IV (Decadron). See Pearls for more information.

• Place the patient on oral antibiotics for 5-7 days. Selected recommended antibiotics include amoxicillin plus clavulanate (Augmentin) or clindamycin.

Airway protection should be considered for large abscesses. If the airway is in doubt, consider intubation and drainage under general anesthesia. ^[14] Tracheostomy is rarely necessary.

The carotid artery lies lateral and posterior to the tonsil. Take care that the incision and dissection procedure is not performed too deep or in a lateral position. Be aware of anatomic variants of the internal carotid artery (aka aberrant carotid artery). In some patients, the carotid can be much more midline and can be in danger of iatrogenic injury during needle aspiration or incision and drainage.

The incision is made superior to the tonsil in the area of the soft palate. An incision in the tonsil itself causes excessive bleeding and may miss the abscess, which is located in the peritonsillar soft tissues of the soft palate.

Although physical examination is sufficient in most cases to make the diagnosis of a PTA, consider a contrast-enhanced CT scan of the neck or an intraoral ultrasound ^[3] to aid in the diagnosis or to evaluate for associated complications such as deep space neck abscess, especially if the patient has an ipsilateral neck mass or fluctuance.

In some cases, simply injecting local anesthetic into the area of maximal fluctuance can localize the abscess cavity to make the incision and drainage very simple.

Patients with a PTA usually report pain in this area of the neck

Group A streptococci ^[15] and anaerobic ^[16] bacteria are the 2 most common bacteria isolated from PTA cultures. ^[17] Antibiotics used for the treatment of PTA should cover gram-positive and anaerobic bacteria. ^{[18, 19]}

A single high dose of steroid prior to antibiotic therapy can be useful in improving symptoms of patients with PTAs postdrainage. ^[13]

Complications may include the following:

• Severe bleeding

• Aspiration of abscess contents into the patient's airway

• Pain from inadequate anesthesia

Steroids as adjuvant treatment

Prior to 2003, no studies on the use of steroids in peritonsillar abscess (PTA) were published. In a study for severe, acute pharyngitis, adjuvant steroids demonstrated benefit. The authors randomized 58 patients to receive either 1 dose of intramuscular dexamethasone (10 mg) or placebo. Subjects receiving steroids reported faster improvement in throat pain than control subjects. ^[20]

In 2004, a group in Turkey examined the use of a single high-dose steroid. Sixty-two patients treated with needle aspiration were assigned to receive either intravenous antibiotic treatment plus placebo OR intravenous antibiotic treatment plus a dose of steroid. Clinical outcomes revealed a statistically significant difference between the groups when evaluating throat pain, fever, trismus, and hours hospitalized. ^[13]

A 2014 study found that 10 mg IV dexamethasone combined with drainage and IV antibiotics resulted in less pain at 24 hours when compared to placebo. However, the effect is short-lived; differences disappeared by 48 hours and 7 days. ^[21]

Outpatient vs inpatient management in children

In a study out of the Eastern Virginia Medical School looking at 83 consecutive children with PTA, 56% were discharged the same day as treatment; the remaining 44% required admission for intravenous fluids and postoperative airway observation. The decision to hospitalize for intravenous hydration, pain control, and airway monitoring was individualized and based on the child's age, comorbidities, family resources, and the patient or family's ability to obtain and administer antibiotics, pain medications, and fluids on an outpatient basis. The overall mean stay was 0.9 days. ^[22]

Bilateral peritonsillar abscesses

Sudies have found the incidence of bilateral PTAs to be between 3.9%-6.5%. ^{[23, 24]} In one study, younger age, absence of a deviated uvula, and a higher C-reactive protein value were the clinical features associated with bilateral PTAs in multivariate analysis. ^[23] Bilateral PTAs can present as a diagnostic challange as the uvula might not be deviated, which is a common physical exam finding for typical PTAs.