The Article: Costantino TG, Satz WA, Dehnkamp W, Goett H. “Randomized trial comparing intraoral ultrasound to landmark-based needle aspiration in patients with suspected peritonsillar abscess.” Acad Emerg Med. 2012 Jun;19(6):626-31. doi: 10.1111/j.1553-2712.2012.01380.x. PMID: 22687177
The Idea: Previously, the approach to diagnosis and treating peritonsillar abscesses (PTA) by emergency physicians (EP) has been primary based on physical exam findings such as peritonsillar swelling or uvular deviation. This approach has been found to have only ~75% sensitivity and ~50% specificity. To improve diagnostic and procedural success, EPs can use intraoral US for better visualization and localization of PTA. This study aimed to compare the diagnostic accuracy of EPs of peritonsillar abscess using intraoral ultrasound vs the landmark technique (visual inspection).
The Study: This study was a prospective, randomized, controlled clinical trial at a large, urban, university hospital from October 2008 to December 2010.
Inclusion Criteria: Patients 18 years old or greater with the ability to consent, who presented to the ED with symptoms consistent with a PTA that warranted needle aspiration (at EP’s discretion).
Exclusion Criteria: Clinically unstable patients due to compromised airway or hemodynamic instability.
There were 28 participants in the study, randomized equally into one of two study arms. One arm used the traditional landmark (LM) approach to aspiration, the other used US to guide drainage of the PTA. Every participant was instructed to follow up in the ED after 2 days to assess for clinical resolution.
Primary outcome: The primary outcome of the study was to determine successful diagnosis of PTA. Since inclusion criteria consisted of patients with clinical exam findings of PTA, all patients in the LM group were needle aspirated. In the US group, only those with a visualized abscess were drained. Success of aspiration was documented as a PTA and unsuccessful aspirations were documented as peritonsillar cellulitis (PTC)
Secondary outcomes: Secondary outcomes were successful aspiration of purulent material, frequency of CT scan, and frequency of ENT consults.
Results: Of the 14 patients aspirated in the LM group, there were 5 successful aspirations and 9 unsuccessful. Of the 9 unsuccessful, 5 were successfully aspirated by ENT. The remaining 4 were diagnosed with PTC. These findings are consistent with a diagnostic accuracy of 64% (95% CI = 39% to 84%) in the LM group. Of the 14 patients in the US group, 8 PTA were visualized on US, all with successful aspirations. 6 patients had visualized PTC on US and were not aspirated. These findings are consistent with a diagnostic accuracy of 100% (95% CI = 75% to 100%) in the US group.
Secondary outcomes: The ENT consult rate was 7% (IQR = 0% to 34%) for US versus 50% (IQR = 27% to 73%) for LM (p = 0.03). The CT usage rate was 0% for US versus 35% for LM
The Takeaway: The importance of findings in this study the significant improvement in diagnostic accuracy of PTA vs PTC by EPs with the use of intraoral ultrasound guidance. Diagnostic accuracy can lead to more successful needle aspiration as well as prevent preforming unnecessary aspirations. In addition, ultrasound usage for PTA diagnosis decreased the need for ENT consults, and decrease the need for CT. Because of these improvements, it should be recommended that EPs preform intraoral US for all suspected PTAs that present to the ED.
Author: Tara Holmes, MS4