Follow-up ultrasonographic findings among children treated conservatively for uncomplicated acute appendicitis

Background Ultrasound is an accurate tool for diagnosing acute appendicitis. Conservative treatment for uncomplicated acute appendicitis is feasible and safe in children. However, no sonographic follow-up results from children with nonoperatively managed acute appendicitis have been reported. Objective To describe the sonographic appearance of the appendix at follow-up ultrasound and to attempt to identify signs predictive of recurrent acute appendicitis. Materials and methods Children diagnosed with uncomplicated acute appendicitis and treated conservatively in our hospital from 2014 to 2019, and who presented for follow-up ultrasound at 3, 6 and 9 months, were included in our study. Clinical, laboratory and ultrasound data were recorded. Results By the end of follow-up, 29 (14.2%) of 204 children in the cohort had developed recurrent acute appendicitis and 175 had recovered uneventfully. On follow-up ultrasound, appendiceal diameter measured > 6 mm in 56/204 (27.5%) cases at 3 months and in 9/26 (34.5%) at 6 months. After 3 months, 102/204 (50%) children had normal appendiceal diameter on ultrasound. Appendiceal diameter > 6 mm was associated with intraluminal fluid or sludge in the appendiceal lumen at 3- and 6-month follow-up (P < 0.001, P = 0.002, respectively). Comparing cases with and without recurrence, at 3-month follow-up, appendiceal diameter > 6 mm was found in 17/29 (58.6%) cases vs. 39/175 (22.3%), respectively (P < 0.001). Appendiceal diameter returned to normal in 12/19 (63.2%) cases in the nonrecurrent acute appendicitis group compared with 2/7 (28.6%) in the recurrent acute appendicitis group (P = 0.05) at the 6-month follow-up. Intraluminal fluid or sludge was detected more frequently in the recurrent acute appendicitis versus the nonrecurrent acute appendicitis group at 3- (P < 0.001) and 6-month (P = 0.001) follow-up. Conclusion Progressive normalization of appendiceal diameter was noted on follow-up ultrasound. The prevalence of both appendiceal diameter > 6 mm and intraluminal fluid or sludge were found to be increased in children who later developed recurrent acute appendicitis. Ultrasound appears to be a useful tool for follow-up in children with conservatively treated uncomplicated acute appendicitis and possibly might help predict recurrence.