Lymphocyte depression as a predictor of postoperative intraabdominal abscess after appendectomy in children

Abstract

Background This study evaluated the efficacy of lymphopenia to predict postappendectomy intraabdominal abscess (IAA) in pediatric complex appendicitis. Methods This single-center retrospective cohort study included appendectomy patients with complex appendicitis from 4/2012 to 10/2014. IAA was diagnosed based on imaging or undergoing a drainage procedure. Labs were used from the closest day prior to abscess diagnosis or day of discharge from index admission. Lymphocyte percentage was categorized based on age-specific cutoffs with lymphopenia defined as a low percentage. Comparisons were made using chi-square or Fisher exact tests for categorical variables and Mann–Whitney U-tests for continuous variables. Results Of 611 appendectomy patients with complicated appendicitis, 551 had WBC and differential. IAA was identified in 79 (12.9%) patients. There were no significant differences in demographics between IAA and non-IAA groups. Patients with IAA had higher rates of leukocytosis (44.3% versus 12.3%, p < 0.001) and higher rates of age-based lymphopenia (84% vs. 46%, p < 0.001). IAA was independently associated with leukocytosis (OR 3.65, p < 0.001) and lymphopenia (OR 4.46, p < 0.001). Patients with leukocytosis and lymphopenia had the highest abscess rate (36%), and those with normal labs had the lowest (3%, p < 0.001). Conclusions Lymphocyte depression is a useful adjunct to predict postoperative IAA in patients with complicated appendicitis. Level of Evidence III