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A peritonsillar abscess is the most common deep infection of the head and neck encountered in young adults in the Emergency Department.1,2 The incidence has remained stable in the United States at 30 cases per 100,000 people.3 The incidence in the United Kingdom has increased 18% over 10 years.3,4 This infection can occur in all age groups. It is relatively rare before the age of 5 years. The highest incidence occurs in teenagers and young adults, and incidence gradually declines after the age of 40.5,6 There is a female-to-male predominance until the age of 14.7 There remains controversy in the literature regarding the optimal antibiotic choice and the mechanism of drainage. The objective for the Emergency Physician remains to make an accurate diagnosis, to institute appropriate care, and to arrange timely follow-up.


Knowledge of oropharynx anatomy is imperative. The anatomy of the oral cavity is relatively simple (Figure 208-1). The peritonsillar abscess can be found posterolateral to the palatine tonsil and posterior to the palatoglossal fold (i.e., arch). Note the close proximity of the internal carotid artery and the facial artery to the peritonsillar abscess (Figure 208-2). Use extreme care to not penetrate too deeply and puncture or lacerate these arteries.

FIGURE 208-1.

Anatomy of the oropharynx as seen through the open mouth.

FIGURE 208-2.

Horizontal section through the mouth and oropharynx. Note the close proximity of the peritonsillar abscess to the internal carotid artery and the facial artery.

The duration of reported symptoms ranges from 2 to 7 days for patients with ultrasound (US)-proven peritonsillar abscesses.8,9 The most common symptoms include fever, sore throat, dysphagia, muffled voice (i.e., the “hot potato” voice), and trismus.10 Physical examination will reveal a nonexudative pharyngitis in the majority of cases, soft palate edema, a bulging prominent tonsil, and uveal deviation away from the abscessed tonsil (Figure 208-3). The differential diagnosis includes intratonsillar abscess, peritonsillar cellulitis, infectious mononucleosis, malignancy, leukemia, odontogenic infections, aberrant carotid arteries, internal carotid artery pseudoaneurysms, and aneurysms of the internal carotid artery. The frequency of bilateral peritonsillar abscesses has been reported to be between 1.9% and 24% with the unsuspected contralateral abscess being discovered during surgery for the acute abscess tonsillectomy.11 The Emergency Physician should maintain a high index of suspicion even if uvular deviation is not noted.

FIGURE 208-3.

A peritonsillar abscess. The abscess displaces the tonsil forward and medially. The uvula is deviated toward the contralateral side. A. Artist illustration. B. Clinical photo. The black arrow identifies the abscessed tonsil. C. A computed tomography scan through the abscess. The red arrow identifies the abscess. ...

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