Ultrasound Accuracy in Diagnosing Appendicitis in Obese Pediatric Patients

The use of ultrasound to diagnose appendicitis in pediatric patients has been growing with the improvement of ultrasound technology and operator skills, but its utility in the increasingly obese pediatric population has not been thoroughly investigated. A retrospective review of all pediatric (≤18 years old) patients with appendicitis who were admitted at a single hospital from 2014 to 2016 was conducted. Patients were stratified into body mass index (BMI) percentile categories based on the centers for disease control guidelines. Comparisons were then made. There were 231 patients with an average BMI percentile of 72.6; 99 (42.9%) who had an ultrasound, of which 54 (54.5%) were positive for acute appendicitis, whereas 43 (43.4%) were nondiagnostic. In patients who had a nondiagnostic ultrasound, 37 had a CT demonstrating acute appendicitis. These were compared with 123 patients who had CT alone demonstrating acute appendicitis. The CT-only group was older (12 vs 9, P < 0.005), tended to be male (78 (63%) vs 15 (41%), P = 0.019), had fewer operations performed (81 (66%) vs 30 (81%), P = 0.048) but had no significant difference in BMI percentile (75.8 vs 71.7, P = 0.465). Ultrasound had a 100 per cent positive predictive value in obese and overweight children. Ultrasound is a reliable study in obese and overweight pediatric patients with acute appendicitis.