Snapshot A 45-year-old woman with polyhydramnios delivers a male infant with Down syndrome. Shortly after birth, the infant vomits greenish-yellow fluid. Imaging reveals two distinct pockets of air in the abdominal region. Introduction Congenital failure of the duodenal lumen to completely recanalize Results in stenosis of the duodenal passageway between the stomach and intestinal tract leads to gastric outlet syndrome Epidemiology > 1:10,000 births ETIOLOGY Pathogenesis Unknown but thought to occur during weeks 8-10 of development Associated with Down syndrome (20-30% of DS cases) and other birth defects as with biliary atresia Presentation Symptoms bilious vomiting that continues despite no feedings as opposed to nonbilious emesis in pyloric stenosis urinary infrequency Physical exam abdominal distention may or may not be present absent meconium imaging Radiograph reveals "double bubble" sign Differential diagnosis for "dobule bubble" includes other causes of duodenal obstruction duodenal atresia, duodenal web or stenosis, annular pancreas, malrotation of the bowel with a midgut volvulus , or Ladd's bands Fetal ultrasound may show polyhydramnios Differential Pyloric stenosis, tracheoesophageal fistula diagnosis Diagnosis based primarily on imaging Treatment Prevention no preventive measures are available at this time Medical management gastric decompression place G-tube to deflate stomach IV hydration and electrolyte control indicated in all patients Surgical intervention surgical correction not an emergency approach depends on anatomic variant Complications Without treatment, condition is lethal Prognosis Full recovery is expected after surgical correction