Summary

Duodenal atresia is a complete occlusion or absence of the duodenal lumen, whereas duodenal stenosis refers to an incomplete obstruction caused by narrowing. Both conditions present with signs of obstruction, including a distended upper abdomen, delayed meconium passage, and vomiting. If the defect is located proximal to the major duodenal papilla, nonbilious vomiting occurs, whereas a defect occurring distal to the papilla causes bilious vomiting. Evidence of polyhydramnios on prenatal ultrasonography may lead to an early diagnosis of duodenal obstruction. An abdominal x-ray typically shows the double bubble sign. Duodenal atresia and stenosis generally have a favorable prognosis and may be surgically treated through duodenoduodenostomy.

Epidemiology

Around 1/5000–10,000 live births
∼ 50% of cases are associated with further anomalies, e.g., bile duct and VACTERL association.
30% of cases are associated with chromosomal abnormalities, especially Down syndrome.

References:^[1]^[2]

Epidemiological data refers to the US, unless otherwise specified.

Pathophysiology

Duodenal atresia occurs when recanalization of the closed duodenum fails to occur or occurs only partially during the embryonic period (usually between the 8^th–10^th week of gestation). Because the development of the duodenum is connected to the growth of the pancreas and the hepatobiliary system, duodenal atresia is commonly associated with anomalies of these organs as well.

References:^[1]

Clinical features

Intrauterine

Polyhydramnios

Postpartum

Vomiting, that is typically bilious if the stenosis is distal to the major duodenal papilla
- Atresia or high-grade stenosis: vomiting few hours after birth
- Mild stenosis: vomiting after a few days
Distended upper abdomen and scaphoid lower abdomen
Delayed meconium passage

References:^[3]^[1]

Diagnostics

Prenatal

Ultrasound
- Polyhydramnios
- Dilation of the stomach and duodenum (proximal to the obstruction) is common.
- Double bubble sign

Postnatal

X-ray of the abdomen
- Double bubble sign
- Gasless distal bowel

References:^[4]^[3]

Differential diagnoses

Jejunal atresia

Definition: absence of the jejunal lumen
Epidemiology: less common than duodenal atresia
Pathophysiology
- Vascular accident in utero → necrosis and reabsorption of the jejunum
- Risk factors: vasoconstrictive drugs (e.g., cocaine, MDMA, or cigarettes) during pregnancy
Clinical features: similar to duodenal atresia
- Polyhydramnios (intrauterine)
- Bilious vomiting and upper abdominal distension (postpartum)
Diagnosis: abdominal x-ray shows a triple bubble sign and gasless colon
Treatment: surgical correction with bypass of the occluded part of bowel is always required

The differential diagnoses listed here are not exhaustive.

Treatment

Preoperative management
- Parenteral nutrition via a central catheter shortly after birth
- Fluid replacement and restoration of the electrolyte balance
- Gastric decompression
Surgery: bypass the atresia or stenosis
- The exact procedure depends on the anatomic findings and associated anomalies
- Common procedure: duodenoduodenostomy or duodenojejunostomy with a proximal transverse-to-distal longitudinal (diamond-shaped) anastomosis

References:^[5]

Prognosis

If diagnosis and treatment occur quickly, the survival rate of isolated duodenal atresia (without further anomalies) is 95%.
The presence of other anomalies worsens the prognosis.

References:^[2]