Duodenal atresia

What it is

Duodenal atresia is complete occlusion or absence of the duodenal lumen, and it is a congenital obstruction. Duodenal stenosis is the incomplete form, an obstruction due to narrowing of the duodenum. Both result from failure, or partial failure, of recanalization of the closed duodenum during the embryonic period, at 8 to 10 weeks of gestation.

Causes and risk

Three associations are asked about together:

• Trisomy 21, that is Down syndrome
• Congenital heart defects
• Prematurity

Polyhydramnios is the antenatal association.

How it presents

Vomiting on day 1 of life is the presentation, with atresia or high-grade stenosis giving vomiting a few hours after birth and mild stenosis giving vomiting only after a few days. Whether the vomit is bilious depends on where the block sits: it is typically bilious if the stenosis is distal to the major duodenal papilla, and non-bilious if the obstruction is above the second part of the duodenum. The abdomen is distended in its upper part and scaphoid below, visible gastric peristalsis may be seen as the stomach tries to overcome the obstruction, and meconium passage is delayed.