PassFinals
Paediatrics

Intussusception

A segment of bowel telescopes into the adjacent segment, dragging its mesentery with it and causing intermittent obstruction, venous congestion, ischaemia and potentially perforation; prompt paediatric-surgical assessment is essential.

In a nutshell

Intussusception is telescoping of bowel with its mesentery, causing intermittent obstruction and progressive ischaemia. Suspect it in a young child with episodic colicky pain, pallor or lethargy, vomiting and intermittent wellness; redcurrant-jelly stool is late. Resuscitate, obtain urgent ultrasound and use air-enema reduction if stable, with surgery for an unsafe or failed reduction.

Classic presentation

A young child has repeated episodes of severe colicky pain, draws up the legs and becomes pale or lethargic, then appears better between episodes; vomiting and a mass or bloody mucus may follow.

Key points

  • Intermittent wellness does not exclude intussusception.
  • Redcurrant-jelly stool is late ischaemic bleeding and must not be awaited.
  • Ultrasound is the usual first diagnostic investigation and shows the target or doughnut sign.
  • Resuscitate, keep nil by mouth and contact paediatric surgery early.
  • Air enema is used for a stable child when there is no peritonism or suspected perforation.
  • Surgery is required when the child is too unwell, perforation or ischaemia is suspected, or reduction fails.
  • Observe after reduction and give urgent recurrence safety-netting.

First-line investigation

Urgent abdominal ultrasound showing the target or doughnut sign.

Management

Resuscitate and refer

  • Treat suspected intussusception as a surgical emergency: monitor, gain IV access, keep nil by mouth, give analgesia and contact paediatric surgery early.1,3

Confirm with ultrasound

  • Arrange urgent ultrasound for the target or doughnut sign while assessing perfusion, hydration, vomiting, peritonism and possible perforation.1,2

Reduce with air enema if stable

  • Use image-guided air-enema reduction with surgical support when the child is stable and there is no peritonism or suspected perforation.1,2

Operate when unsafe or unsuccessful

  • Proceed to urgent surgery for shock, peritonism, suspected perforation, severe illness or failed enema reduction; resection may be needed for non-viable bowel.1,2

Observe and safety-net

  • Observe after reduction until clinically stable and feeding, then give immediate-return advice for recurrent colic, pallor, lethargy, vomiting or bloody stool.1

Exam traps

  • Do not wait for redcurrant-jelly stool: it is a late sign.
  • A child may look well between painful episodes.
  • Peritonism, shock or suspected perforation makes enema reduction unsafe and requires surgery.
  • A plain abdominal X-ray cannot reliably exclude intussusception.
  • Older children or recurrent cases need specialist assessment for a pathological lead point.

Illustrations

Bowel telescoping mechanismDiagram showing bowel invagination, mesenteric traction and venous compression.PassFinals · original
Target sign of intussusception on ultrasoundTransverse ultrasound showing concentric alternating bowel-wall rings producing the target or doughnut sign.Frank Gaillard, Wikimedia Commons · CC-BY-SA-3.0
Air-enema reductionIllustration of radiological air-enema pressure pushing the intussuscepted bowel back into position.PassFinals · original

Key sources

  1. Cambridge University Hospitals NHS Foundation Trust: Intussusception in children (Paediatric diagnosis, resuscitation, ultrasound, air enema, surgery, observation and recurrence advice; approved 29 July 2025)
  2. Great Ormond Street Hospital: Treatment of intussusception using an air enema (Specialist paediatric radiology and surgical reduction pathway, including indications, monitoring and perforation risk)
  3. NHSGGC paediatric emergency guidance: suspected intussusception (Urgent ultrasound, resuscitation, analgesia, surgical review and air-enema or operative pathway)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.