Duodenal Atresia: Characteristics and Associations

Etiology and Pathophysiology

• Duodenal atresia results from failure of recanalization of the primitive gut lumen during embryologic development, not from intrauterine mesenteric vascular accidents (which is the mechanism for jejunoileal atresia) 1
• The condition commonly presents as a mucosal web with normal muscular wall (type I atresia), rather than complete separation of duodenal segments 2

Clinical Presentation

• Bilious vomiting within the first 2 days of life is a common presentation due to proximal intestinal obstruction 3, 1
• Abdominal distension occurs due to accumulation of fluid and gas proximal to the obstruction 1
• Passage of meconium is typically absent or abnormal at birth due to the complete obstruction of the duodenum 1

Diagnostic Features

• The classic "double bubble" sign on radiographs indicates proximal dilation of the duodenum and stomach, suggesting duodenal atresia 3
• In cases with no gas distally, upper GI series is usually not necessary as the diagnosis is typically clear from plain radiographs 3

Differential Diagnosis

• Must be distinguished from jejunoileal atresia, which is caused by intrauterine mesenteric vascular accidents rather than failure of recanalization 1
• Malrotation with midgut volvulus can present similarly with bilious vomiting but has a different embryologic cause 4, 1
• Hirschsprung disease, which results from neural crest migration failure, should also be considered in the differential diagnosis 1