Purpose or Case Report: Peritonsillar abscess (PTA), as a consequence of acute tonsillitis is a very commonly encountered deep infection of the head and neck. Diagnosis of PTA and differentiation from uncomplicated cellulitis based on clinical findings has been shown to be very unreliable. Therefore, imaging diagnosis is a key step in management given the possible need for drainage, in addition to antibiotic therapy. Due to the widespread availability of real-time US, high resolution imaging of the tonsillar and peritonsillar tissue and confident diagnosis of PTA via an intraoral approach is feasible, with literature reporting sensitivities of 90-100%. This offers a valuable diagnostic alternative to the high radiation dose and expense of contrast enhanced CT in the pediatric population. The aim of this exhibit is to review sonographic technique, as well as the normal and pathologic appearance of the palatine tonsils via both transoral and transcutaneous approaches illustrated by a case series obtained at our institution.
Methods & Materials: For transcutaneous approach, a high frequency linear transducer is placed just inferior to the angle of the mandible, with the patient in an erect position and contralateral rotation of the head. For transoral ultrasound, an intra-cavity transducer is placed directly on the affected tonsil with the patient’s mouth open. Introduction of the probe into the mouth can be performed by the patient him/herself to increase patient comfort.
Results: The normal sonographic appearance of the palatine tonsil is a small 10-20mm, oval-structure that has a homogenous low-level echo texture. Tonsillar cellulitis presents as enlarged tonsils greater than 20mm with a homogeneous or striated appearance, whereas PTA displays a heterogeneous or cystic appearance, typically with discrete fluid collection (see figure 1). Although enlarged tonsils are readily visualized with transcutaneous technique, the ability to image the tonsil as a superficial structure with the intracavitary probe allows for superior visualization of the tonsillar tissue as compared to transcutaneous technique secondary to the improved lateral resolution (see figure 2).
Conclusions: Using a series of case examples, this exhibit displays the value of intraoral sonography of the tonsillar fossa and ease of differentiation of abscess from uncomplicated tonsillitis using this approach.