Peritonsillar Abscess in Emergency Medicine

Peritonsillar abscesses (PTAs) are common infections of the head and neck region; they comprise approximately 30% of soft tissue head and neck abscesses.[2] With an incidence of about 1 in 10,000, it is the most common deep space infection of the head and neck that presents to the emergency department.[3]

A study by Johnson using the 2012 Nationwide Emergency Department Sample, the 2012 National (Nationwide) Inpatient Sample, and the 2013 Nationwide Readmissions Database estimated the number of emergency department visits in the United States for peritonsillar abscess to be 62,787, with the estimated number of inpatient admissions and readmissions for the condition being 15,095 and 267, respectively. Eighty percent of the emergency department patients were discharged home after receiving nonoperative therapy, while 50% of the patients admitted to the hospital were treated surgically.[1]

Physicians must be aware of the typical clinical presentation of and diagnostic strategies for peritonsillar abscess, in order to quickly diagnose and appropriately treat patients with the condition. In this way, complications and further propagation of the infectious process can be prevented.

A peritonsillar abscess is shown in the image below.

Right peritonsillar abscess. The soft palate, which is erythematous and edematous, is displaced anteriorly. The patient has a "hot potato–sounding" voice.

The two palatine tonsils are on the lateral walls of the oropharynx, within the depression between the anterior and posterior tonsillar pillars. Each pillar is composed primarily of the glossopalatine and the pharyngopalatine muscles.

During embryonic development, the tonsils arise from the second pharyngeal pouch as buds of endodermal cells.[4] The tonsils then grow irregularly and reach their ultimate size and shape at approximately age 6-7 years.

Each tonsil is surrounded by a capsule, a specialized portion of the intrapharyngeal aponeurosis that covers the medial portion of the tonsils and provides a path for blood vessels and nerves.[4] It is within this potential space, between the tonsil and capsule, that peritonsillar abscesses form.[5] Note that the peritonsillar space is anatomically contiguous with several deeper spaces, and infections can potentially involve the parapharyngeal and retropharyngeal spaces.[6]

Peritonsillar abscesses usually progress from tonsillitis to cellulitis and ultimately to abscess formation. Weber glands are thought to also play a key role in the etiology of the infection. These mucous salivary glands are located superior to the tonsil in the soft palate and clear the tonsillar area of debris. If these glands become inflamed, local cellulitis develops. As the infection progresses, inflammation worsens and results in tissue necrosis and pus formation, most commonly just above the superior pole of the tonsil where the glands are located.[5]

Klug et al, citing evidence for peritonsillar abscess as a complication of acute tonsillitis and as a consequence of Weber gland infection, hypothesized that peritonsillar abscesses develop when bacteria infect the tonsillar mucosa and then, using the salivary duct system, spread to the peritonsillar space.[7]

A multi-center, prospective, observational case-control study by Lepelletier et al suggested that self-medication with systemic anti-inflammatory drugs may increase the risk of peritonsillar abscess. Male gender and smoking were also linked to the condition. The study compared 120 cases of peritonsillar abscess with 143 cases of sore throat without peritonsillar abscess.[8]

United States

In the United States, the incidence of peritonsillar abscess has been estimated at 30 cases per 100,000 persons per year, accounting for approximately 45,000 cases annually.It has also been estimated to result in at least $150 million a year in health care expenditures.[9] Most infections occur during November to December and April to May, which coincide with the highest incidence rates of streptococcal pharyngitis and exudative tonsillitis.[5]

International

A higher rate is reported internationally due to recurrence and antibiotic resistance.

Mortality of peritonsillar abscess is unknown. Morbidity of peritonsillar abscess is due mostly to pain, cost of treatment, lost time from work and school, and complications.

Using data from the National (Nationwide) Inpatient Sample, a study by Qureshi et al found evidence that retropharyngeal abscess is occurring at an increasing rate among adult inpatients with peritonsillar abscess. According to the investigators, between 2003 and 2010 the annual rate at which retropharyngeal abscess occurred concurrently with peritonsillar abscess rose from 0.5% to 1.4% among inpatients aged 18 years or older. The study also indicated that patient age affects concurrence of the two conditions, with the likelihood that retropharyngeal abscess will complicate peritonsillar abscess increasing in patients aged 40 years or older.[10]

A literature review by Klug et al found descending mediastinitis to be the most frequently reported complication in peritonsillar abscess, followed by parapharyngeal and retropharyngeal abscess, necrotizing fasciitis, and Lemierre syndrome. Overall, 17 different complications were found in the studies examined, with the overall mortality rate being 10%. The investigators also reported that male gender and age over 40 years appeared to be complication risk factors.[11]

Race

No racial predilection of peritonsillar abscess is noted.

Sex

The male-to-female ratio for peritonsillar abscess is considered to be equal, although the previously mentioned study by Lepelletier did suggest that male gender is a risk factor.[8]

Age

Peritonsillar abscess can occur in anyone aged 10-60 years according to one source, although peritonsillar abscess is most commonly seen in those aged 20-40 years.[12] The younger children who get peritonsillar abscess are often immunocompromised.

Symptoms of peritonsillar abscess usually begin 3-5 days prior to evaluation.

• Fever

• Malaise

• Headache

• Neck pain

• Throat pain markedly more severe on the affected side and occasionally referred to the ipsilateral ear

• Dysphagia

• Change in voice

• Otalgia

• Odynophagia

Physical findings of peritonsillar abscess include the following:

• Mild/moderate distress

• Fever

• Tachycardia

• Dehydration

• Drooling, salivation, trouble handling oral secretions

• Trismus resulting from pain from inflammation and spasm of masticator muscles

• Hot potato/muffled voice

• Rancid or fetor breath

• Cervical lymphadenitis in the anterior chain

• Asymmetric tonsillar hypertrophy

• Localized fluctuance

• Inferior and medial displacement of the tonsil

• Contralateral deviation of the uvula

• Erythema of the tonsil

• Exudates on the tonsil

Peritonsillar abscesses are usually polymicrobial. A prospective study carried out to elucidate significant pathogens involved in peritonsillar abscesses demonstrated that the most prominent aerobic pathogen was Streptococcus pyogenes. Other aerobic pathogens isolated included Staphylococcus aureus,Neisseria species, and Corynebacterium species. In the same study, the most common anaerobic species found was Fusobacterium necrophorum, an obligate, anaerobic, Gram-negative rod. Other Fusobacterium species and Prevotella species were also isolated. A literature review demonstrated that the Streptococcus milleri group, a facultative anaerobic group of bacteria, is also commonly associated with peritonsillar infection. Though these studies are European publications, studies within the United States have demonstrated similar results.[5, 13, 4, 14, 15]

The aforementioned literature review by Klug et al reported that the most prevalent bacteria in peritonsillar abscess are viridans group streptococci (25%), beta-hemolytic streptococci (20%), Fusobacterium necrophorum (13%), Staphylococcus aureus (11%), Prevotella species (10%), and Bacteroides species (9%).[11]

No definitive studies are required to diagnose peritonsillar abscess. Physicians may consider basic laboratory tests (ie, CBC, electrolytes, C-reactive protein) if the patient has significant comorbidities.

Monospot test/heterophile antibody test can be performed to rule out infectious mononucleosis if the etiology is unclear. Infectious mononucleosis can coexist in 1.5-6% of patients with peritonsillar abscesses.[16]

Culture of the fluid from needle aspiration may be performed to guide antibiotic selection or changes. A recent literature review recommends obtaining aspirate culture in those at risk of infection with resistant organisms (ie, those with recurrent or persistent infection, diabetes, or immunocompromise).[16]

Blood cultures may be indicated if the clinical presentation is severe.

Lateral soft tissue neck radiographs may help rule out other causes. The anteroposterior (AP) view of the neck may demonstrate distortion of soft tissue.

A study by Huang et al indicated that ultrasonography is an accurate means of evaluating patients for peritonsillar abscess, finding that compared with patients diagnosed with peritonsillar abscess via traditional examination methods and/or CT scanning, those who were diagnosed with transcervical ultrasonography demonstrated significant reductions in surgical drainage and length of hospital stay.[17]

Intraoral ultrasonography (US) has a sensitivity of 95.2% and specificity of 78.5%. This method is cost-effective and fast, although it does require a cooperative patient. A study carried out at an academic level I emergency department included 43 patients who received intraoral US for suspected peritonsillar abscess. Thirty-five were diagnosed with an abscess on US, and these patients subsequently received needle aspiration using US guidance. There was one false positive, but no patients returned unexpectedly after drainage, and, on reexamination, there was no evidence of persistent or recurrent peritonsillar abscess or cellulitis. This study supports the use of US for both the diagnosis and treatment of peritonsillar abscesses.[18]

Another study demonstrated that intraoral US can reliably distinguish peritonsillar abscess from peritonsillar cellulitis; this not only helps direct treatment, but it also results in fewer CT scans of the neck and fewer ENT consultations.[19] Prior studies of US use have shown similar successful results.

Head and neck CT scanning with intravenous (IV) contrast is useful if incision and drainage fails, if the patient cannot open his or her mouth, or if the patient is young (age < 7 years) and uncooperative. A hypodense fluid collection with rim enhancement may be seen in the affected tonsil. Foreign bodies, such as fish or chicken bones, may also be found as an inciting factor.

Three options are available for acute surgical management of peritonsillar abscess: needle aspiration, incision and drainage, and quinsy tonsillectomy (eg, simultaneous tonsillectomy with open abscess drainage).

A systematic review by Johnson et al attempted to determine the best technique for acute surgical management. Forty-two articles were analyzed. Five level I clinical studies indicated that all 3 techniques were equally effective for initial management.[2]

Needle aspiration

The main advantages of needle aspiration are ease of the procedure, decreased pain for the patient, and cost-effectiveness.[9, 2]

The patient should be sitting upright.

Lidocaine with epinephrine should be used to anesthetize the area.

A 16- to 18-gauge needle with a 10-mL syringe should be used to aspirate from the area that is most fluctuant.

A needle guard may be used to prevent accidental carotid artery puncture due to the tip of the needle migrating too far posteriorly. Only 0.5 cm of the needle needs to be exposed. If a needle guard is unavailable, a curved clamp can be used to expose a small portion of the needle before inserting it into the area for aspiration.

Aspirate at the superior pole initially, as this is the most common place for abscess development. Aspiration of the middle one third and then the lower one third should then be attempted if pus is not returned from the superior pole. Also, see Drainage, Peritonsillar Abscess.

Pus is aspirated through a wide-bore needle from the right peritonsillar abscess. An additional incision will be made to drain any other pus pockets.

Abscess incision and drainage[20]

The patient should be sitting upright with a pan available to spit out any blood or pus.

A tongue depressor is used to retract the tongue.

After local infiltration with lidocaine with epinephrine, a No. 11 blade scalpel is used to make a small incision 0.5 cm long and no more than 1 cm deep. Be certain that the incision is not extended laterally as the carotid artery lies in that vicinity.

Use a small hemostat to probe the abscess and release the pus.

To prevent the risk of aspiration, allow the patient to hold the Yankauer catheter tip and to suction the pus.

Tonsillectomy

No clear evidence indicates that routine elective tonsillectomy is indicated to prevent future peritonsillar abscesses. However, if the patient has had multiple recurrent episodes of peritonsillar abscesses or has other clear indications (ie, sleep-disordered breathing), elective tonsillectomy should be considered.[9]

Additionally, if general anesthesia is required because of the patient's age or lack of cooperation, tonsillectomy should be considered, as the complication rate is low. Although the data do not support this, consideration for the most definitive procedure should be made.[9, 2]

An Italian study indicated that following incision and drainage for peritonsillar abscess, the risk of abscess recurrence is not significantly different between patients who are subsequently managed conservatively and those who undergo tonsillectomy, as long as the patients have not had previous episodes of peritonsillar abscess. The study involved 4199 hospital inpatients who, after incision and drainage, received either conservative treatment (2667 patients) or tonsillectomy (1532 patients). Although the tonsillectomy rate among these patients fell by 45% between 1997 and 2006, the investigators found that the incidence of hospitalization for peritonsillar abscess remained stable during this period.[21]

Prehospital care for peritonsillar abscess includes transport with supplemental oxygen.

Evaluation of peritonsillar abscesses begins with ABCs, paying close attention to the patient's airway. If the patient's airway is compromised, immediate endotracheal intubation is indicated. If this cannot be completed, a cricothyroidotomy or a tracheostomy may be required. Alternatively, if the resources are available, one study concluded that awake fiberoptic bronchoscopy was the method of choice for intubating patients with significant pharyngeal edema.[9]

These patients are often dehydrated because of their avoidance of food and liquid and may need fluid resuscitation.

Antipyretics should be administered for elevated temperature; adequate analgesia should be provided for pain.

Acute surgical management should be carried out as discussed above, if indicated.

Empiric antibiotics should be administered.

Steroids are often used as adjunctive treatment.[22] A recent literature review carried out by Powell and Wilson indicates that patients treated with steroids have statistically significant reductions in pain and hospital stay.[16]

A literature review by Lee et al also suggested that corticosteroids are effective in the treatment of peritonsillar abscess, finding significant improvement during the first 24 hours following treatment in patients who underwent corticosteroid therapy with regard to pain-related parameters, body temperature, and dysphagia compared with patients treated with placebo. In addition, the corticosteroid patients had a significantly greater discharge rate than did the placebo group during the first 5 days posttreatment. However, by 48 hours posttreatment, patients in the corticosteroid and placebo groups had an equal tendency to return to normal activities and dietary intake.[23]

Patients can be managed in an outpatient setting unless they show signs of toxicity, sepsis, airway compromise, inability to swallow, or other complications.

An otolaryngologist may be required if the patient's presentation is severe. An anesthesiologist or surgeon may be required for management of a difficult airway.

Apart from drainage, antibiotics are a main component of therapy for peritonsillar abscesses.

Antibiotic therapy should begin prior to drainage and culture results.

Though several studies have shown intravenous penicillin alone is clinically effective (provided the abscess is adequately drained), other studies have reported that greater than 50% of cultures grow beta-lactamase – producing anaerobes, leading to the tendency to use broader-spectrum antibiotics such as clindamycin or a second- or third-generation oral cephalosporin.

In those patients allergic to penicillin, clindamycin is a good choice.

Analgesics and throat washes are recommended.

As mentioned above, some physicians report using adjunctive steroids to decrease edema and pain.

Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

Clindamycin (Cleocin)

Semisynthetic antibiotic produced by 7(S)-chloro-substitution of 7(R)-hydroxyl group of parent compound lincomycin. Inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Widely distributes in the body without penetration of CNS. Protein bound and excreted by the liver and kidneys.

Oral or parenteral antibiotic for anaerobic or susceptible streptococcal, pneumococcal, or staphylococcal species. Considered to have good absorption into bloodstream in both oral and parental forms.

Penicillin G benzathine (Bicillin L-A)

DOC in combination with metronidazole. Effective in approximately 98% of patients. Interferes with synthesis of cell wall mucopeptide during active multiplication, resulting in bactericidal activity against susceptible microorganisms.

Metronidazole (Flagyl)

DOC in combination with penicillin. Effective in approximately 98% of treated patients.

Imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa. Appears to be absorbed into the cells of microorganisms that contain nitroreductase. Unstable intermediate compounds are formed that bind DNA and inhibit synthesis, causing cell death.

Nafcillin (Unipen)

Initial therapy for suspected penicillin G-resistant streptococcal or staphylococcal infections.

Use parenteral therapy initially in severe infections. Change to PO therapy as condition warrants.

Because of thrombophlebitis, particularly in elderly persons, administer parenterally only for short term (1-2 d); change to PO route as clinically indicated.

Erythromycin (E.E.S, Ery-Tab, Erythrocin)

Inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. For treatment of staphylococcal (including S aureus) and streptococcal infections.

Indicated if patient is allergic to penicillin.

Class Summary

Corticosteroids may be indicated to decrease inflammation.

Dexamethasone (Baycadron, Decadron, Dexamethasone Intensol)

Dexamethasone, a potent glucocorticoid for which mineralocorticoid activity is minimal to absent, reduces inflammation through suppression of polymorphonuclear leukocyte (PMN) migration and reduction of capillary permeability. It also inhibits prostaglandin and proinflammatory cytokines.

Prednisone (Deltasone, Prednisone Intensol, Rayos)

Prednisone, a glucocorticoid with mild mineralocorticoid activity and moderate anti-inflammatory effects, reduces inflammation through suppression of polymorphonuclear leukocyte (PMN) migration and reduction of capillary permeability. It also inhibits prostaglandin and proinflammatory cytokines.

If outpatient care is used, the patient can be discharged on an appropriate regimen of antibiotics and pain medications.

Relative indications for elective tonsillectomy can be identified in almost a third of all patients who present with peritonsillar abscess (eg, recurrent tonsillitis).

Observation, imaging studies, airway management, and intravenous hydration may be required.

Other methods of operative management strategy may be indicated and should be performed by an otolaryngologist.

Recurrence obviates the need for a second hospitalization for interval tonsillectomy after needle decompression or incision and drainage.

To prevent recurrence, interval tonsillectomy may be considered 3-4 weeks after resolution of edema and symptoms.

Complications of peritonsillar abscess may include the following:

• Necrotizing soft tissue infection of the neck and chest wall[24]

• Recurrence

• Aspiration, which may lead to pneumonia or pneumonitis

• Cervical abscess

• Mediastinitis

• Meningitis

• Sepsis

• Cerebral abscess

• Jugular vein thrombosis

• Carotid artery rupture/necrosis

• Carotid artery injury (from I&D or needle aspiration)

A retrospective cohort study by Mizuno et al indicated that in adult patients, the risk for recurrence of peritonsillar abscess is reduced in those aged 40 years or older and in patients who have been treated with intravenous antibiotics for at least 3 days, the adjusted hazard ratios (HRs) being 0.69 and 0.85, respectively. The risk of recurrence was reported to be increased in adult patients with a history of recurrent tonsillitis (adjusted HR = 1.79).[25]

Uncomplicated, treated peritonsillar abscess has a resolution rate of 94%. In the United States, the recurrence rate is 10%, regardless of whether a patient is treated with needle aspiration or incision and drainage.[16] The rate of recurrence jumps to 15% internationally.

For patient education resources, see the Ear, Nose, and Throat Center, as well as Peritonsillar Abscess, Tonsillitis, and Antibiotics.