Different Clinical Features and Lower Scores in Clinical Scoring Systems for Appendicitis in Preschool Children: Comparison with School Age Onset

Purpose: To clarify the clinical features of appendicitis in preschool children and to explore clinical appendicitis scoring systems in this age group. Methods: We retrospectively collected data on 142 children, aged 10 years or younger, with confirmed diagnosis of appendicitis based on surgical and pathologic findings. Enrolled subjects were divided into two groups: Group 1 (preschool children aged ${\leq}5$ years, n=41) and Group 2 (school children aged >5 to ${\leq}10$ years, n=101). Data analyzed included clinical presentation, laboratory findings, the pediatric appendicitis score (PAS), and the modified Alvarado score (MAS). Results: The most common presenting symptom was abdominal pain in both groups (92.7% vs. 97.0%). Other presenting symptoms were as follows: fever (65.9%), vomiting (68.3%), right lower quadrant (RLQ) localization (24.4%), anorexia (14.6%), and diarrhea (7.3%) in Group 1, and RLQ localization (74.3%), vomiting (71.3%), anorexia (52.5%), fever (47.5%), and diarrhea (11.9%) in Group 2. Perforation and abscess occurred more frequently in Group 1 than in Group 2 (43.9% vs. 12.9%, p<0.001; 34.1% vs. 5.0%, p<0.001; respectively). PAS and MAS were lower in Group 1 than in Group 2 ($4.09{\pm}1.97$ vs. $6.91{\pm}1.61$, p=0.048; $4.65{\pm}1.79$ vs. $6.51{\pm}1.39$, p=0.012; respectively). Conclusion: In preschool children, appendicitis often presents with atypical features, more rapid progression, and higher incidence of complications. This age group is more likely to have lower PAS and MAS than those of school children.