# Intussusception > NEET-PG Surgery notes on intussusception: classic triad, ultrasound target sign, pneumatic enema reduction, contraindications and surgical technique. - Canonical URL: https://prepelephant.com/topics/neet-pg/surgery/intussusception - Exam / course: NEET-PG · Subject: Surgery - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Intussusception", PrepElephant, https://prepelephant.com/topics/neet-pg/surgery/intussusception ## Direct answer Intussusception is the telescoping of one bowel segment into the adjoining distal segment and the commonest cause of intestinal obstruction in infants between six months and two years — usually idiopathic ileocolic, led by a hypertrophied Peyer patch after a viral illness. The classic triad is intermittent colicky pain, vomiting and red-currant-jelly stool — a late sign — with a palpable sausage-shaped mass in the right hypochondrium and emptiness of the right iliac fossa (sign de Dance). Ultrasound shows the target or doughnut sign in transverse section and the pseudokidney sign longitudinally; in a well-resuscitated child without peritonitis, treatment is pneumatic or hydrostatic enema reduction, with surgery for failed reduction, perforation or a pathological lead point. ## What you must remember - **Epidemiology:** peak age six months to two years with male predominance; below three months and above three years, search for a pathological lead point. - **Lead points:** hypertrophied Peyer patches (viral, and reported after rotavirus vaccination) in infants; Meckel diverticulum, polyp, duplication cyst or lymphoma in older children. - **Clinical triad:** colicky pain with drawing-up of legs, vomiting, then red-currant-jelly stool; a sausage-shaped mass with right iliac fossa emptiness completes the picture. - **Ultrasound signs:** target or doughnut sign in transverse section, pseudokidney sign longitudinally — first-line imaging, no radiation, operator-dependent but highly sensitive in experienced hands. - **Reduction rules:** pneumatic (air, controlled pressure with a manometer) or hydrostatic (saline under ultrasound) enema under resuscitated conditions; success in roughly 70-80% of appropriately selected cases. - **Contraindications to enema reduction:** peritonitis, free air, established shock, significant guarding — and frank rectal bleeding with shock suggests gangrenous bowel needing theatre first. - **Recurrence:** about one in ten reduced intussusceptions recur, mostly within the first days to months, and repeat enema reduction is usually appropriate. - **Surgery:** open or laparoscopic manual reduction by milking the intussusceptum distally — never pulling it out; resection with anastomosis or stoma for gangrene, perforation or a pathological lead point. ## From assessment to reduction Walk the pathway as it happens at 3 a.m. A previously well 9-month-old has screamed in 15-minute cycles for eight hours, vomited feeds, and now passes blood-stained mucus. He is mildly dehydrated but alert, with a tender right upper quadrant mass; the abdomen is soft. Intravenous access, fluid bolus and analgesia come first, because reducing an intussusception in a hypovolaemic child invites collapse. Ultrasound shows a right-sided target sign with preserved wall flow on colour Doppler — bowel viability likely. Pneumatic reduction follows: a catheter in the rectum, buttocks taped, air insufflated under manometric control with fluoroscopic or ultrasound watching, three attempts with brief intervals, and free reflux of air into the ileum announcing success. The child is observed for 24 hours for recurrence and fed once recovered from anaesthesia-free sedation. Had he arrived toxic, with guarding and bloody shock, the straight-to-theatre rule applies: laparotomy, gentle retrograde milking of the intussusception, resection of non-viable bowel, and a search for a lead point such as a Meckel diverticulum. ## Where candidates lose marks The single most-repeated error is treating red-currant-jelly stool as an early feature — it is late, present in a minority, and its absence never reassures; pain cycles with a mass and vomiting carry the diagnosis. The second is enrolling a peritonitic child for enema reduction: shock, guarding and free air are absolute contraindications, and the vignette of the "toxic infant with a rigid abdomen" is testing exactly that gate. Third, forget not the older child: a four-year-old with intussusception has a lead point until imaging and surgery prove otherwise — Meckel diverticulum, juvenile polyp or lymphoma — and a segmental small-bowel intussusception on ultrasound in a pain-free child may be transient and benign, but a persistent one with a lead point is not. Fourth, the technique sentence examiners wait for: the intussusceptum is milked back, never pulled, because pulling tears the oedematous serosa. Finally, the post-reduction conversation — recurrence of about 10%, managed in the first instance by repeat enema, with surgery reserved for repeated recurrence or a lead point. ## Frequently asked questions ### What is the classic triad and mass of intussusception? Intermittent colicky pain with legs drawn up, vomiting and red-currant-jelly stool, with a sausage-shaped mass in the upper abdomen and emptiness in the right iliac fossa (sign de Dance). ### Which ultrasound signs confirm intussusception? The transverse target or doughnut sign and the longitudinal pseudokidney sign, with colour Doppler assessing bowel-wall perfusion. ### When is enema reduction contraindicated? With peritonitis, free intraperitoneal air, established shock or significant guarding — these children go to theatre for surgical reduction or resection. ### Why is the intussusceptum milked and never pulled? Pulling tears the engorged, friable serosa of the intussuscepted bowel; gentle retrograde milking from the distal end protects an already compromised segment. ### What changes in an older child with intussusception? A pathological lead point — Meckel diverticulum, polyp or lymphoma — is likely, so imaging, surgical reduction and lead-point management replace straightforward enema reduction.