# Duodenal Atresia and Intestinal Malrotation

> Duodenal atresia and intestinal malrotation for NEET-PG Paediatrics: double bubble sign, Down syndrome link, midgut volvulus and the Ladd procedure.

- Canonical URL: https://prepelephant.com/topics/neet-pg/paediatrics/duodenal-atresia-and-intestinal-malrotation
- Exam / course: NEET-PG · Subject: Paediatrics
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Nelson Textbook of Pediatrics; Ashcraft's Pediatric Surgery; IAP Textbook of Pediatrics
- How to cite: "Duodenal Atresia and Intestinal Malrotation", PrepElephant, https://prepelephant.com/topics/neet-pg/paediatrics/duodenal-atresia-and-intestinal-malrotation

## Direct answer

Duodenal atresia is complete obstruction of the duodenum, typically showing vomiting in the first day and a double bubble sign on abdominal X-ray. Intestinal malrotation is abnormal fixation of the bowel mesentery that predisposes to midgut volvulus, a surgical emergency. Duodenal atresia is strongly associated with Down syndrome, and malrotation with volvulus is corrected by the Ladd procedure.

## What you must remember

- **Double bubble sign:** a dilated stomach and proximal duodenum on X-ray with no gas distal to them, typical of duodenal atresia.
- **Vomiting pattern:** bilious when the atresia lies distal to the ampulla of Vater, which is the usual position, and non-bilious when it is proximal.
- **Down syndrome:** a substantial proportion of duodenal atresia cases have trisomy 21, so karyotyping is advised.
- **Polyhydramnios:** a common antenatal clue in duodenal atresia.
- **Malrotation anatomy:** the duodenojejunal junction lies to the right of the midline, and the caecum is abnormally placed.
- **Midgut volvulus:** twisting of the mesentery causes bilious vomiting and bowel ischaemia, which needs urgent surgery.
- **Ladd procedure:** division of Ladd bands, widening of the mesenteric base and appendicectomy, with small bowel placed on the right and colon on the left.

## Evaluating bilious vomiting in a newborn

Bilious vomiting in a newborn is an emergency until malrotation with volvulus is excluded, so the approach is urgent and structured. The steps below follow the usual sequence in neonatal surgery, though the exact timing of imaging and surgery depends on the baby's condition.

1. **Take the history:** note polyhydramnios, abdominal distension, the passage of meconium and whether the vomit is bilious.
2. **Obtain an abdominal X-ray:** a double bubble sign suggests duodenal atresia, while gas distal to the stomach argues against it.
3. **Image the upper gastrointestinal tract:** a contrast study showing a corkscrew duodenum points to midgut volvulus in malrotation.
4. **Resuscitate and decompress:** start intravenous fluids, correct electrolytes and place a nasogastric tube to decompress the stomach.
5. **Operate urgently if volvulus is found:** perform the Ladd procedure, assess bowel viability and resect any necrotic segment.
6. **Screen for associated anomalies:** check for Down syndrome, cardiac anomalies and annular pancreas, which commonly accompany duodenal atresia.

## Where the exam tries to catch you

Duodenal atresia and malrotation questions test the imaging signs, the vomiting pattern and the surgical logic.

- **Trap:** confusing the double bubble with the single gastric dilatation of pyloric stenosis. — **Correct:** pyloric stenosis gives non-bilious projectile vomiting with a single dilated stomach, while duodenal atresia gives the double bubble.
- **Trap:** assuming vomiting in duodenal atresia is always non-bilious. — **Correct:** most atresias lie distal to the ampulla, so bilious vomiting is the usual pattern.
- **Trap:** treating malrotation as harmless because the baby is well. — **Correct:** malrotation carries a risk of volvulus at any age, so surgical planning is considered once it is found.

## Frequently asked questions

### What is the double bubble sign in duodenal atresia?

The double bubble sign in duodenal atresia is the appearance on abdominal X-ray of a dilated stomach and dilated proximal duodenum, with no gas distal to them. It reflects obstruction in the duodenum. Its presence strongly suggests duodenal atresia in a vomiting newborn.

### Why is duodenal atresia linked to Down syndrome?

Duodenal atresia is linked to Down syndrome because a substantial proportion of affected babies have trisomy 21. Karyotyping is therefore advised in neonates with duodenal atresia. The association is one of the most frequently tested in paediatric examinations.

### What is midgut volvulus in intestinal malrotation?

Midgut volvulus is twisting of the small bowel around the superior mesenteric artery axis, which occurs because malrotation leaves the mesentery abnormally fixed. It causes bilious vomiting, abdominal distension and possible bowel ischaemia. It is a surgical emergency that needs prompt intervention.

### What is the Ladd procedure?

The Ladd procedure is the surgical correction of intestinal malrotation. It involves dividing the Ladd bands, widening the mesenteric base and performing an appendicectomy, with the small bowel placed on the right and the colon on the left. It is used for midgut volvulus and for symptomatic malrotation.