Appendicitis or non-specific abdominal pain in pre-school children: When to request abdominal ultrasound?

Aim The aim of this study is to determine the most useful diagnostic tools to differentiate appendicitis from non-specific abdominal pain (NSAP) in pre-school children. Methods We prospectively evaluated all children aged 5 years or younger admitted for suspected appendicitis at a paediatric emergency department during 5 years. Cases of NSAP and appendicitis were enrolled according to inclusion and exclusion criteria. The different variables collected were assessed by statistic and diagnostic accuracy studies. Results A total of 82 patients were studied: 27 cases of NSAP and 55 cases of appendicitis. We found no symptoms or signs with a high power of discrimination between both processes. Complicated cases of appendicitis begin to appear when the duration of symptoms exceeds 12 h. Among laboratory tests, C-reactive protein (CRP) value >34 mg/L was the variable with a greater association to appendicitis (odds ratio 9.8). Abdominal ultrasound (US) had high sensitivity and specificity to differentiate appendicitis, significantly improving its diagnostic accuracy when the duration of symptoms exceeds 12 h. Conclusions A good history and physical examination are important in the diagnostic process, but reliable physical signs can be difficult to elicit in pre-school children. CRP and abdominal US are useful investigations that can improve diagnostic accuracy. According to our results, abdominal pain duration longer than 12 h or CRP value >34 mg/L should be an indication to perform an abdominal US in pre-school children with right lower quadrant tenderness.