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Key Points
Often presents due to uterine size greater than the size of dates as a result of polyhydramnios.
Characteristically diagnosed by ultrasound examination, which shows a “double bubble” sign.
Differential diagnosis includes annular pancreas, malrotation, gastric or duodenal duplication, and preduodenal portal vein.
Associated with trisomy 21 in 30% of cases. Amniocentesis should be performed.
Associated with congenital heart disease in 17% to 33% of cases. Echocardiography should be performed.
Polyhydramnios rarely develops before 24 weeks’ gestation but can contribute to preterm labor.
Delivery should occur in a tertiary center with pediatric surgical and neonatal expertise available.
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Duodenal atresia, or stenosis, is a leading cause of intestinal obstruction in newborns and one of the most common gastrointestinal anomalies that can be diagnosed prenatally. A commonly held developmental theory is that at 1 month of gestation, the lumen of the duodenum is thought to be obliterated by proliferating epithelium. This solid core of epithelium undergoes vacuolization and recanalization, restoring the lumen. Failure of recanalization of the solid stage is thought to result in duodenal atresia or stenosis. Atresia is more common than stenosis and occurs in approximately 70% of cases (Boyden et al., 1967; Skandalakis et al., 1994). Skandalakis et al. (1994) have described 3 types of duodenal atresia. The most common duodenal anomaly (69% of cases) is membranous mucosal atresia (type I) with an intact muscular wall. The proximal duodenum is ballooned out while the duodenum distal to the atresia is narrowed. This mucosal membrane may take on the shape of a “wind sock” because of peristalsis and increased proximal intraluminal pressure (Rowe et al., 1968). The origin of the wind-sock membrane is usually intimately associated with the ampulla of Vater. A type II duodenal atresia is rare (2% of cases) and has a short fibrous cord connecting the two ends of the atretic duodenum. Type III duodenal atresia has a complete separation between the two ends of the duodenum and can be associated with biliary tract anomalies in 6% of cases (Reid, 1973a and b; Jona and Berlin et al., 1976; Paine and Noblett, 1977; Knechtle and Filston, 1990). Duodenal stenosis accounts for the remaining 23% of cases. These anatomic relations are rarely evident sonographically. An annular pancreas occurs in 20% to 30% of patients with duodenal atresia or stenosis (Fonkalsrud et al., 1969; Reid, 1973a and b; Wesley and Mahour, 1977). The developmental relationship between annular pancreas and duodenal atresia and stenosis is unclear.
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An annular pancreas can produce extrinsic compression and result in stenosis, but it is more commonly associated with an intrinsic obstruction due to complete atresia (Merrill and Raffensperger, 1976).
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Duodenal stenosis or atresia occurs in approximately 1 in 10,000 livebirths (Fonkalsrud et al., 1969; ...