Written by Megan Hilbert
Spoon Feed
Pediatric patients with a positive ultrasound (US) and Pediatric Appendicitis Risk Calculator (pARC) score ≥ 25% are highly likely to have pathology-proven appendicitis.
Are you [h]appy with your pediatric appendicitis care?
Why do we keep talking about pediatric appendicitis? The false positive rate of pediatric appendiceal ultrasound is up to 10%, and the current United States negative appendectomy rate is 6.7%, while the benchmark goal is to be < 2%. To appropriately meet this “quality indicator of delivery of care”, surgical candidates need to be at very high risk for pathology. With the recently validated pARC score, can we further increase identification of patients with true appendicitis?
This was a retrospective, single-center, tertiary care pediatric ED cohort study with participants taken from prior prospective cohort (parent) studies. Included patients had concern for appendicitis and positive ultrasound. The pARC score was then calculated for each patient. A pARC ≥ 25% (previously identified as moderate to severe risk) plus positive US had sensitivity of 86.7% (95%CI 82.3-90.4), specificity of 87.9% (95%CI 71.8-96.6), positive predictive value of 98.5% (95%CI 96.1–99.6), and negative predictive value of 42.6% (95%CI 30.7-55.2) for identifying pathology-proven appendicitis. Note: All had predetermined p value < 0.05 to reach significance.
How will this change my practice?
Where this truly becomes important is in patients who have a positive ultrasound, but a pARC score < 25%. In those cases, this study suggests that instead of pursuing surgical management, we should pursue further imaging or re-evaluation. After all, surgical intervention is not without its own risks, and we want to make sure that we are only sending patients to the OR who absolutely need it.
Editor’s note: After ultrasound, 89.9% had pathology-confirmed appendicitis (that is the pretest probability). Ultrasound + pARC ≥25% has LR+ 7.17. So, the post-test probability increases to 98.5%. Use JournalFeed’s EBM calculators to see this in action. ~ Clay Smith
Source
Identification of Children With a Positive Ultrasound and Appendicitis Using the Pediatric Appendicitis Risk Calculator: Retrospective Cohort Study. Acad Emerg Med. 2025 Aug 1. doi: 10.1111/acem.70118. Epub ahead of print. PMID: 40748264.
