Intraoral Ultrasound vs Landmark-based Aspiration for Peritonsillar Abscess

Emily Peoples, MD | Emergency Medicine PGY1

The Article:

Randomized Trial Comparing Intraoral Ultrasound to Landmark-based Needle Aspiration in Patients with Suspected Peritonsillar Abscess. Costantino et al. (2012). Academic Emergency Medicine. 19(6): 626-631.

The Idea:

To compare the diagnostic accuracy of Emergency Physicians for detecting peritonsillar abscess or peritonsillar cellulitis using either intraoral US or initial needle aspiration after visual inspection (the landmark technique).

The Study:

This was a prospective, randomized, controlled clinical trial of a convenience sample of adult patients who presented to a single, large, urban university hospital. Patients were enrolled if they presented with signs and symptoms that were judged to be a peritonsillar abscess. These patients were randomized to receive intraoral US or to undergo landmark (LM) drainage. All patients were enrolled by the attending physician and the procedure was performed by a second or third year emergency medicine resident. The US was performed using an 8–5 MHz intracavitary transducer immediately prior to the procedure. The probe was then withdrawn and the provider who did the US also performed the needle aspiration. The LM was performed using visual landmarks in a superior to inferior approach until pus was obtained or at least two sticks were performed. Anesthesia was standardized. Patients returned for follow-up in 2 days where a final diagnosis was rendered. The primary outcome was successful diagnosis. Secondary outcomes included successful aspiration of purulent material from patients whose final diagnosis was peritonsillar abscess, the frequency of CT scanning, and the frequency of ENT consultation within each study group.

The Findings:

A total of 28 patients were enrolled, with 14 in each arm. US established the correct diagnosis more often than LM [(100%, 95% confidence interval [CI] = 75% to 100% vs. 64%, 95% CI = 39% to 84%; p = 0.04)]. US also led to more successful aspiration of purulent material by the EP than LM in patients with PTA [(100%, 95% CI = 63% to 100% vs. 50%, 95% CI = 24% to 76%; p = 0.04)]. The ENT consult rate was 7% (95% CI = 0% to 34%) for US versus 50% (95% CI = 27% to 73%) for LM (p = 0.03). The CT usage rate was 0% for US versus 35% for LM (p = 0.04).

The Takeaway: 

Initial intraoral US can reliably diagnose peritonsillar abscess and peritonsillar cellulitis and leads to greater success of needle aspiration compared to the traditional landmark method.