Gastroschisis versus omphalocele
In gastroschisis the bowel (the gut) pushes out through the abdominal wall with no covering, whereas in omphalocele the contents that herniate (push out) are wrapped in a sac.
Remember
Gastroschisis is uncovered bowel lying in amniotic fluid (the fluid surrounding the foetus in the womb), which damages it and delays feeding. Omphalocele is bowel inside a covering sac.
Memory aid
gastroschisis is the naked gut and omphalocele is the gut in a bag
Gastroschisis is bowel with nothing over it, and omphalocele is bowel wrapped in a bag.
Two key conditions leave the gut tube outside the abdominal cavity: omphalocele, where the gut fails to return to the abdomen, and gastroschisis, where the abdominal wall fails to close. The ventral (front) body wall forms when the embryo folds from side to side in the fourth week. In omphalocele the herniated contents are covered, but in gastroschisis they are not.
In gastroschisis the abdominal wall fails to close, usually to the right of the umbilical cord. The peritoneum is the thin lining of the abdominal cavity. The bowel, and sometimes other organs, pushes out with no peritoneal covering.
Because nothing covers it, the bowel lies in amniotic fluid for the rest of the pregnancy. The fluid irritates it, so it becomes thickened and inflamed, and it moves its contents poorly. Feeds are therefore slow to establish after birth, and gut function often takes several weeks to recover.
In omphalocele (also called exomphalos) the gut that normally bulges into the cord early in development fails to return to the abdomen. The herniated contents stay inside a thin membranous sac at the umbilical ring, the opening where the cord attaches. The sac shields the contents, so intestinal function may be preserved, and feeding depends on the defect's size and on any associated anomalies (abnormalities of other organs).
Omphalocele is more often associated with other anomalies and with genetic conditions, which gives it a worse overall prognosis. Gastroschisis is usually an isolated abnormality, and genetic conditions rarely accompany it.
Key facts
- Gastroschisis
- the abdominal wall fails to close and the bowel herniates with no peritoneal covering.
- Omphalocele
- the herniated contents sit inside a membranous sac at the umbilical ring.
- Site
- gastroschisis usually lies to the right of the umbilical cord, while the omphalocele pattern is a defect at the umbilical ring.
- Feeding
- gastroschisis bowel is inflamed and slow, so feeding is usually delayed, whereas function may be preserved in omphalocele.
- Associations
- genetic conditions and other anomalies are more common with omphalocele, whereas genetic conditions rarely accompany gastroschisis, which is usually an isolated abnormality.
Exam traps
- A peritoneal sac over herniated bowel points to omphalocele, because in gastroschisis nothing covers the bowel.
- A higher risk of chromosomal abnormalities does not mark out gastroschisis, because genetic conditions go with omphalocele and rarely accompany gastroschisis.
- Normal bowel function from the first feed is not expected after repair of gastroschisis, because the bowel often shows slowed movement and feeding is usually delayed.
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