Appendicitis in children with acute abdominal pain in primary care, a retrospective cohort study.

Background: General practitioners (GPs) face a diagnostic challenge when assessing acute abdominal pain in children. However, no information is available on the current diagnostic process or the diagnostic accuracy of history and physical examination in primary care settings.

Objective: To describe the diagnostic process for acute abdominal pain among children in primary care, focusing on appendicitis, and to assess the diagnostic accuracy of individual clinical features.

Methods: A retrospective cohort study in Dutch primary care, using the Integrated Primary Care Information database. Children aged 4-18 years were included if they had no history of appendicitis and presented with acute abdominal pain during 2010-2016. We evaluated GP management and the diagnostic accuracy of clinical features for appendicitis. Pre- and post-test probabilities were calculated for each clinical feature and compared with the probability of appendicitis after GP assessment.

Results: Out of 5691 children, 944 (16.6%) were referred and 291 (5.1%) had appendicitis, of whom 55 (18.9%) were initially misdiagnosed. The pre-test probability (i.e. of appendicitis in evaluated children) varied from 3% (rigidity) to 28% (migratory pain). Concerning post-test probabilities, positive values for rebound pain (32.1%) and guarding (35.8%) and the negative value for right lower quadrant tenderness (0.6%) were superior to overall GP assessment (29.6% and 1.1%, respectively).

Conclusions: GP assessment will miss almost one-fifth of children with appendicitis at their first presentation, and about two-third of GP referrals will be negative. The presence of specific signs can increase or decrease the likelihood of appendicitis, emphasising the importance of a physical examination.