Congenital Gastrointestinal Tract Disorders

The abdominal organs are derived primarily from endoderm, which forms the primitive gut tube. The gut tube is divided into 3 regions: foregut, midgut, and hindgut. The foregut gives rise to the lining of the GI tract from the esophagus to the upper duodenum, as well as the liver, gallbladder, and pancreas. The midgut gives rise to the GI tract lining between the midduodenum and midtransverse colon. The hindgut gives rise to the GI tract lining from the midtransverse colon through the upper anal canal. The mesoderm gives rise to the muscles of the GI tract wall, connective tissue (including the mesenteries and omenta), and the vasculature. The ectoderm gives rise to the nerve tissue and the lining of the lower anal canal.

Intestinal malrotation is a congenital anomaly that results from failure of the GI tract to undergo normal rotation around the mesenteric vessels during embryologic development. This condition can result in several anatomic patterns characterized by abnormal location and attachments of the abdominal cavity's intestines. These anomalies can be clinically silent or present with a number of complications, the most catastrophic of which is midgut volvulus. Intestinal malrotation usually presents in infancy as an acute onset of bilious vomiting. Definitive diagnosis is established with the upper GI series and the treatment is emergent surgery.

Omphalocele is a congenital anterior abdominal wall defect in which the intestines are covered by peritoneum and amniotic membranes. The condition results from the failure of the midgut to return to the abdominal cavity by 10 weeks' gestation. Omphalocele is frequently associated with genetic syndromes and chromosomal abnormalities. Prenatal diagnosis can be made by prenatal ultrasound, maternal blood elevated ⍺-fetoprotein, and fetal chromosomal analysis. Treatment includes immediate hemodynamic stabilization followed by primary or staged surgical repair.

Gastroschisis is a congenital abdominal wall defect characterized by the complete lack of closure of the abdominal musculature. A portion of intestine does not return to the abdominal cavity, thereby remaining in its early embryonic herniated state but with no coverings. Diagnosis is made by prenatal ultrasonography. Findings include a paraumbilical wall defect with uncovered herniated intestines. Fetal surveillance and bowel monitoring are done to measure fetal growth and amniotic fluid volume, as well as observe any bowel changes. The mode and timing of delivery depend on these factors. Neonatal care includes protection of the exposed bowel, fluid resuscitation, and airway maintenance. Primary closure can be performed within hours of birth. The presence of a large gastroschisis or thickened and dilated bowel warrants delayed closure, with the use a bowel covering or “silo,” and serial bowel reduction.