Ultrasound-guided drainage of peritonsillar abscess: shoot with your hockey-stick.

Abstract

Peritonsillar abscess (PTA) is a complication of pharyngitis and tonsillitis, and the most common deep space infection of the head and neck [1]. Often clinical examination alone cannot accurately distinguish between peritonsillar cellulitis and abscess. This can lead to inappropriate management, failed drainage attempts, and unnecessary complications. Some clinicians rely on computerized tomography (CT scans) or otolaryngologist consultation to confirm the diagnosis or assist in drainage. Point-of-care ultrasound is able to confirm the diagnosis of PTA, as well as differentiate PTA from cellulitis [1]. Ultrasound is also able to provide either static or dynamic guidance for drainage procedures [2]. Previous case studies report that intra-oral ultrasound has a sensitivity of 89 % and a specificity approaching 100 % for the diagnosis of PTA. A CT scan has a specificity of 75 % [3]. Typically, an endocavitary probe is used for the procedure [4]. Linear array probes have been used for transcutaneous imaging through the neck, but intraoral use has not been described [5]. This case report describes the diagnosis and drainage of PTA made with a linear array ‘‘hockeystick’’ probe intra-orally. This probe is unique in that it is shorter than typical endocavitary probes, and thinner than typical linear array probes, making it ideal for use within a confined space such as the oral cavity (Fig. 1a). We believe the novel use of this transducer provides better access to the oral cavity, is more comfortable for the patient, and provides superior imaging of the peritonsillar area compared with the endocavitary probe. A 23-year-old woman was presented to the Emergency Department (ED) complaining of severe throat pain for 2 days associated with fever, chills and odynophagia. The patient was tachycardiac and febrile on arrival. The head and neck examination revealed erythematous pharynx, swollen tonsils with bilateral white exudates, slight bulging of the right peritonsillar space without uvular deviation, some trismus, and right-sided anterior cervical lymphadenopathy. The patient was not drooling, had no audible stridor, and displayed no other signs of upper airway compromise. The remaining history and physical examinations were non-contributory. A PTA was suspected, and a focused ultrasound study of the painful area was performed to differentiate an abscess from simple pharyngitis or tonsillitis. After providing topical analgesia with Cetacaine spray, the patient’s pharyngeal cavity was examined via intra-oral ultrasound. It was determined that due to the patient’s trismus it would be difficult to insert an endocavitary transducer. Instead, we chose the L14-5sp linear array (aka ‘‘hockey-stick’’) transducer (ZONARE Medical Systems, Inc, Mountain View, CA). The probe was covered with a sterile barrier, and placed directly over the area of maximal swelling. A right-sided PTA was clearly visualized (Fig. 1b, c). The abscess was immediately drained at the bedside utilizing static ultrasound guidance. The patient was administered an initial dose of clindamycin in the ED, and was discharged home with oral antibiotic therapy and otolaryngology clinic follow-up. The diagnosis and drainage of PTA with an ultrasound study improves accuracy and decreases complications [1]. Not only is an ultrasound study able to identify the abscess & Adam Ash adamash4@hotmail.com