ultrasound diagnosis of fatal anomalies

GASTROSCHISIS
Associated malformations: Malrotation of the
intestines is almost always an accompanying
feature. Intestinal atresia in 5–15% of cases and
other extraintestinal anomalies (5%) are also detected.
Ultrasound findings: Small-bowel and largebowel
loops are found outside of the abdominal
cavity floating freely in the amniotic fluid. The actual
wall defect usually lies in the lower right
quadrant of the abdomen, and is often difficult to
pinpoint. The smaller the defect, the more severe
is the restriction of blood flow to the intestines,
and the greater damage that can be expected. If
the small-bowel distension exceeds 1.8 cm, then
a long-termdamage of the intestines is probable.
The assumption that in late pregnancy the intestinal
wall is damaged due to contact with the
amniotic fluid is disputed. Ischemia due to restricted
blood flow or torsion of the mesentery
may be a more likely cause of the bowel damage.
In many cases, hydramnios develops as a result
of bowel obstruction. Intrauterine growth restriction
frequently coexists. Growth restriction may
be diagnosed incorrectly, as the abdominal circumference
appears too small due to evisceration
of abdominal contents.
Differential diagnosis: It is often difficult to distinguish
between gastroschisis and a ruptured
omphalocele containing loops of bowel, as the
location of the umbilical vessels relative to the
abdominal wall defect cannot be determined exactly—a
major criterion for differentiating be-
Fig. 6.7 Laparoschisis. Cross-section of the fetal
abdomen, showing a large defect in the anterior
abdominal wall and evisceration of liver and bowel,
at12+2weeks.
Fig. 6.8 Laparoschisis. Same situation, showing a
section at the frontal level through the herniated
liver and small bowel.
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