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Gastroschisis is congenital abdominal
wall defect though which intraperitoneal contents protrude (Fig. 396-1). The defect occurs to the right
of the umbilical cord and can range in size from 2 to 5 cm. The
bowel typically appears edematous and inflamed and may be covered
by a fibrinous peel. The most commonly eviscerated organs include
the intestines and gonads. Gastroschisis occurs in younger mothers,1 with
a total incidence of one in 3000 live births.2 Several
studies have reported a recent increase in the incidence of gastroschisis.3-5
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Gastroschisis occurs during the sixth or seventh week of gestation. The
right umbilical vein naturally involutes, leaving one umbilical vein
and two umbilical arteries. It is hypothesized that the right abdominal
wall suffers from vascular compromise, which results in gastroschisis.6,7 This
explains why gastroschisis always occurs to the right of the umbilicus.
Two other hypotheses exist for the formation of gastroschisis. One
involves the defective development of the mesenchyme on the anterior
abdominal wall. Anecdotally, omphalocele membrane rupture and subsequent
growth of skin to the right and lateral to the umbilicus was documented
by ultrasound; the newborn appearance was that of a gastroschisis.8
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Maternal and environmental factors have been implicated in the development
of gastroschisis. In animal models, folic acid deficiency, maternal
hypoxia, and salicylates have been linked to abdominal wall defects.9 The
use of vasoconstrictive agents, such as pseudoephedrine, cocaine,
and cigarettes, in early pregnancy have been postulated to increase
the risk of gastroschisis.10 Maternal use of salicylates
and acetaminophen has also been implicated in the development of gastroschisis.11 Elevated
atrazine levels, a chemical found in pesticides in drinking water,
has recently been correlated with a regional increased incidence
of gastroschisis in the United States.12
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Infants with gastroschisis tend to be born prematurely. There
is some evidence that gastroschisis infants allowed to deliver after
36 weeks have a stillborn rate of approximately 10%.13 Consequently,
mothers of gastroschisis infants are induced to deliver at 36 to
37 weeks, when lung maturity is reached.
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Ten percent of infants with gastroschisis have an associated
intestinal atresia of varying lengths. It is thought that the atresia
results from in utero segmental intestinal volvulus. This is made
more likely by the fact that the intestines float in the amniotic
fluid without the protection of the peritoneal cavity. Occasionally,
the gastroschisis defect closes completely around the mesenteric
pedicle, causing the midgut to be ischemic and reabsorbed prior
to birth.
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The intestines of infants with gastroschisis have an inherent
dysmotility. In most gastroschisis infants, this manifests as a
prolonged ileus after closure of the abdominal wall. The average
time to start feeds after abdominal wall closure is 21 days, ...