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Malrotation and midgut volvulus
Bilious (green) vomiting in a newborn is midgut volvulus until proved otherwise — the whole midgut hangs on a narrow mesenteric base and can die within hours, so an urgent upper GI contrast study is done or the child goes straight to surgery.
Why it matters in the exam
Malrotation arises when fetal rotation of the gut is incomplete: the caecum stays in the upper abdomen, Ladd's bands cross the duodenum and cause extrinsic obstruction, and the mesenteric base is narrow. The exam shows a newborn or infant with green vomiting, sometimes with a soft, non-distended abdomen at first — distension, blood in the stool and shock are late signs of ischaemia.
The decisive test is an upper GI contrast study (UGI): the duodenojejunal junction (ligament of Treitz) is not left of the spine at the level of the pylorus, and in volvulus there is a "corkscrew" appearance or a cut-off of contrast. On ultrasound the SMV lies to the left of the SMA and a "whirlpool sign" may be seen. A child who is unstable with high suspicion goes straight to theatre.
The Ladd procedure includes: counter-clockwise detorsion of the volvulus, division of Ladd's bands, widening of the mesenteric base, appendicectomy (because it will later lie in an unexpected place) and placing the small bowel on the right and the colon on the left. Recurrent volvulus after a Ladd procedure is uncommon (a few per cent), but adhesive obstruction is possible. Malrotation accompanies CDH, abdominal wall defects and heterotaxy.
Most children with volvulus present in the first month of life and the great majority in the first year, but volvulus can occur at any age, even in adults. In an older child the presentation may be vague: recurrent abdominal pain, intermittent vomiting, malabsorption or poor growth. In volvulus with extensive necrosis, resection can leave short bowel syndrome, so at surgery bowel of doubtful viability is preserved and looked at again.
Key points
- Green vomiting in a newborn — volvulus until proved otherwise.
- UGI is the test of choice; DJ junction in an abnormal position.
- A child in shock — straight to theatre.
- Ladd procedure: detorsion, bands, mesentery, appendix.
- Malrotation accompanies CDH, abdominal wall defects and heterotaxy.
Summary table
| Stage | Finding | Meaning | Action |
|---|---|---|---|
| Clinical | Green vomiting in a newborn | Volvulus until proved otherwise | Gastric tube, fluids, immediate surgical review |
| UGI | DJ junction right of the spine or low | Malrotation | Ladd procedure |
| UGI | Corkscrew or duodenal cut-off | Volvulus | Emergency surgery |
| Ultrasound | SMV left of the SMA, whirlpool sign | Supports malrotation and volvulus | Does not replace UGI when unclear |
| Surgery | Counter-clockwise detorsion, band division, appendicectomy | Prevents recurrence and later diagnostic confusion | Some have necrosis — resection or a "second look" |
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Sources
- Holcomb and Ashcraft's Pediatric Surgery, 7th edition (2019) — Malrotation
- ACR Appropriateness Criteria: Vomiting in Infants, 2019 — Bilious vomiting
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.