Jejunal and ileal atresia !
- Malformation
A stretch of small bowel is missing or closed because it lost its blood supply before birth; the newborn vomits bile and becomes distended.
Updated 2026-11-01
See it in 3D: Jejunum · Ileum · Superior mesenteric artery
What it is
Jejunoileal atresia is a congenital interruption of the small bowel lumen. Unlike duodenal atresia, it is caused by an intrauterine vascular accident in mesenteric branches: the segment that loses its blood supply necroses and is resorbed after the bowel has already formed. It is a common cause of neonatal bowel obstruction and is associated with gastroschisis, intrauterine volvulus and cystic fibrosis.
Embryological cause
- After the bowel has formed and recanalized, a volvulus, intussusception, internal hernia or the constriction of a gastroschisis compresses mesenteric branches.
- The ischaemic segment necroses and is resorbed, leaving a membrane, a fibrous cord or a gap in the mesentery.
- Type IIIb: occlusion of the distal superior mesenteric artery; the distal ileum coils around an ileocolic artery.
- Type IV: multiple atresias along the bowel.
How it presents
- Bilious vomiting in the first 24 hours.
- Abdominal distension, more marked in distal atresias.
- No meconium, or only mucus plugs.
- Polyhydramnios in proximal atresias.
- History of gastroschisis, intrauterine volvulus or cystic fibrosis.
Diagnosis
- Prenatal ultrasound: dilated loops and polyhydramnios.
- X-ray: dilated proximal loops with fluid levels and no distal gas; triple bubble in high jejunal atresia.
- Contrast enema: microcolon; helps separate it from meconium ileus and Hirschsprung disease.
- In ileal atresia, cystic fibrosis is investigated (sweat test or genetics).
Test yourself
Think of the answer, then tap the question to see it.
What mechanism causes jejunoileal atresia?
An intrauterine vascular accident in mesenteric branches that kills an already formed segment, which is then resorbed.
How does it differ from duodenal atresia?
Duodenal atresia comes from failed recanalization and is linked to Down syndrome; jejunoileal atresia is ischaemic and rarely chromosomal.
What is apple peel atresia?
Type IIIb: the distal superior mesenteric artery is missing and the ileum spirals around a single artery.
Which genetic disease is investigated in a newborn with ileal atresia?
Cystic fibrosis, because meconium ileus can cause volvulus and ileal atresia.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Duodenal atresia and stenosis
- Omphalocele and gastroschisis
- Malrotation and midgut volvulus
- Midgut: physiological herniation and rotation
- Hirschsprung disease (congenital aganglionic megacolon)
- Amniotic fluid: polyhydramnios and oligohydramnios
Related conditions
Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.
Sources: Ileal Atresia (StatPearls Publishing (NCBI Bookshelf), 2023); Embryology, Midgut (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.