A 4-year-old child presents with acute onset colicky abdominal pain, palpable abdominal mass, and currant jelly stools. Clinical suspicion for intussusception is high. What is the most appropriate next investigation?

Explanation

## Investigation of Choice for Suspected Intussusception in Children **Key Point:** Abdominal ultrasound is the investigation of choice for suspected intussusception in children — it is non-invasive, radiation-free, highly sensitive and specific, and allows real-time assessment of the intussusceptum and intussuscipiens. ### Why Ultrasound is First-Line in Pediatric Intussusception **High-Yield:** Ultrasound offers: - **Sensitivity 95–100%** and **specificity 95–100%** for intussusception - **No radiation exposure** — critical in pediatric population - **Real-time visualization** — allows assessment of bowel peristalsis and reducibility - **Identification of the "target sign"** — concentric rings of intussuscepted bowel on transverse view - **Assessment of complications** — free fluid, bowel wall thickening, signs of ischemia - **Guidance for therapeutic intervention** — ultrasound-guided hydrostatic or pneumatic reduction ### Classic Ultrasound Findings | Finding | Description | Significance | |---|---|---| | **Target sign** | Concentric rings of bowel on transverse view | Pathognomonic for intussusception | | **Pseudo-kidney sign** | Longitudinal view of intussuscepted bowel | Confirms diagnosis | | **Free fluid** | Peritoneal fluid collection | May indicate ischemia or perforation | | **Bowel wall thickening** | >4 mm | Suggests ischemia | | **Absent peristalsis** | Lack of bowel movement | Sign of ischemia | ### Clinical Pearl In a child with classic presentation (colicky pain, palpable mass, currant jelly stools), ultrasound not only confirms diagnosis but also allows **therapeutic reduction** in the same setting using hydrostatic (saline) or pneumatic (air) enema under ultrasound guidance — avoiding need for surgery in 60–90% of cases if performed early. **Mnemonic:** **CURED** — Currant jelly stools, Ultrasound first-line, Reduction possible, Early intervention, Diagnosis confirmed. ### Why Other Modalities Are Not First-Line **Warning:** Plain radiography has low sensitivity (50–60%) and may show only non-specific signs of obstruction; it does not confirm intussusception. CT exposes the child to significant radiation and is reserved for cases with complications or atypical presentations. Barium enema is now rarely used as both diagnostic and therapeutic modality has been replaced by ultrasound-guided reduction in most pediatric centers. **High-Yield:** Ultrasound is the only investigation that is both diagnostic AND therapeutic in pediatric intussusception.