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Question
20 year-old female presents with sore throat, right throat fullness, difficulty speaking for 2-3 days. A bedside ultrasound and subsequent CT was obtained as seen below. What's the diagnosis?
Answer
Peritonsillar Abscess
The ultrasound image is a transcutaneous approach with a linear transducer that is placed at the angle of the mandible of the affected side. This is an alternative approach to an intra-oral ultrasound with the endocavitary transducer if the patient has trismus.
- Peritonsillar abscess (PTA) is often taught as a clinical diagnosis; however, 36% are often peritonsillar cellulitis (PTC)
- Sensitivity and specificity of clinical diagnosis of PTA are 78% and 50%, respectively
- Classically, providers attempt blind needle aspirations (landmark-based)
- Blind needle aspiration is unreliable for diagnosis of PTA with a false-negative rate of 10-24%
- Intraoral sonography sensitivity: 90-100%
- Using ultrasound can avoid unnecessary use of CTs and blind needle asprations
Take Home Points:
- Consider intra-oral US for diagnosis of PTA vs. PTC and to reduce unecessary radiation with CT
- Consider transcutaneous US to evaluate for PTA in the setting of trismus
- Consider intra-oral US-guided needle aspiration of PTA vs. blind needle aspiration
How to do an intra-oral US-guided needle aspiration of PTA, check out:
http://www.ultrasoundpodcast.com/2012/01/episode-21-full-peritonsillar-abscess-podcast/
For a brief video on how to perform a transcutaneous US for PTA:
https://www.youtube.com/watch?v=JkIYOhKCweI&t=28s
References
Halm BM, Ng C, Larrabee YC. Diagnosis of a Peritonsillar Abscess by Transcutaneous Point-of-Care Ultrasound in the Pediatric Emergency Department. Pediatr Emerg Care. 2016;32(7):489-92.
Rehrer M, Mantuani D, Nagdev A. Identification of peritonsillar abscess by transcutaneous cervical ultrasound. Am J Emerg Med. 2013;31(1):267.e1-3.