Suspected appendicitis in a child
Recommended: Graded compression ultrasound is the preferred imaging study for suspected appendicitis in a child. Pediatric appendicitis imaging follows ALARA — start with graded compression US in skilled hands.
Graded compression ultrasound
Pediatric appendicitis imaging follows ALARA — start with graded compression US in skilled hands. Diagnostic in 50–85%; non-diagnostic when bowel gas or body habitus obscures the appendix. MRI abdomen/pelvis without contrast is preferred second-line (no ionizing radiation, no sedation in most centers with fast protocols). CT only if both US and MRI are unavailable or non-diagnostic.
If the default doesn't apply
Watch-outs
Should NOT be read as 'no appendicitis.' Combined with secondary signs (free fluid, hyperemic ileocecal valve), consider MRI.
Reactive lymph nodes are common — appendix-specific findings (diameter > 6 mm non-compressible, hyperemia, periappendiceal fat) drive the call.
Pearls
- Pediatric appendix > 6 mm AP, non-compressible, with hyperemia is positive.
- Appendicolith on US is highly specific but only ~30% sensitive.
- MRI sensitivity / specificity for pediatric appendicitis approaches CT (> 90% / > 95%) without radiation.
- Image kids with US first — reflexive CT is a relic of adult ED workflows.