Duodenal Atresia

What duodenal atresia is

The duodenum is the C-shaped first part of the small intestine that receives food from the stomach and bile from the liver. Early in pregnancy, the inside of the duodenum is temporarily filled with cells and then reopens. If it fails to reopen properly, a complete blockage (atresia), a membrane (web), or a narrowing (stenosis) remains.

In about 85% of cases the blockage is below the point where bile enters, so vomit is green. When the blockage is above that point, the vomit is clear or milky.

Sometimes the pancreas wraps around the duodenum (annular pancreas) and contributes to the obstruction.

Associated conditions

• Down syndrome: about 30% of babies with duodenal atresia have trisomy 21.
• Congenital heart defects: in about a third.
• Malrotation of the intestine.
• Other atresias: esophageal atresia, intestinal atresia or anorectal malformations.
• Prematurity and low birth weight.
• VACTERL association.

Signs before birth

• Polyhydramnios: too much amniotic fluid, because the baby cannot swallow and absorb fluid normally. It may cause a large bump for dates and premature labor.
• Double bubble sign: two fluid-filled spaces in the upper abdomen on ultrasound, the stomach and the swollen first part of the duodenum, usually visible after about 24 weeks.

When duodenal atresia is suspected, parents are usually offered genetic testing (such as amniocentesis) for Down syndrome, a fetal heart scan (echocardiogram), and planning for delivery at a hospital with neonatal surgery.

Symptoms after birth

• vomiting within the first 24 to 48 hours, often after every feed, usually green
• a swollen upper belly with a flat lower belly
• may pass some meconium initially
• dehydration and weight loss if not treated
• jaundice is common

Babies with duodenal stenosis or a web with a small opening may have milder symptoms and be diagnosed later, sometimes months or years after birth.

Diagnosis

• Abdominal x-ray: shows the classic double bubble with no air beyond it in complete atresia.
• Upper GI contrast study: used if some air passes beyond the duodenum, to rule out malrotation with volvulus, which is a surgical emergency.
• Echocardiogram for heart defects.
• Genetic testing if not already done.
• Blood tests for fluids, electrolytes and blood sugar.

Treatment

Before surgery

• Nasogastric or orogastric tube to drain the stomach and stop vomiting.
• Intravenous fluids and nutrition.
• Correction of electrolyte imbalances.
• Heart assessment, especially before anesthesia.

Surgery

The standard operation is a duodenoduodenostomy: the surgeon connects the duodenum above the blockage to the duodenum below it, bypassing the obstruction. It is usually done within the first few days of life and can be performed open or laparoscopically. A web may be cut out instead. The surgeon also checks for malrotation and other blockages.

After surgery

The swollen duodenum takes time to start moving food effectively, so feeding may be delayed for days to a couple of weeks. Babies receive intravenous nutrition (TPN) until full feeds are tolerated. Most go home within 2 to 4 weeks, depending on other conditions.

Complications

• slow return of duodenal function and feeding difficulties
• leak at the join (uncommon)
• adhesions causing later bowel obstruction
• gastroesophageal reflux
• megaduodenum (a persistently enlarged, sluggish duodenum) requiring further surgery in some
• issues related to associated heart defects or Down syndrome

Outlook

Survival after surgery exceeds 90%. Most deaths are due to severe associated heart defects or prematurity. Most children eat normally and grow well. Long-term follow-up checks for reflux, feeding problems and late complications.

Frequently asked questions

What is duodenal atresia?

It is a birth defect where the first part of the small intestine is blocked, so milk and stomach fluid cannot pass through. Babies vomit, usually green fluid, soon after birth. It is corrected with surgery in the first days of life.

What is the double bubble sign?

The double bubble sign is the appearance of two air- or fluid-filled spaces in the upper abdomen on an x-ray or ultrasound: the stomach and the swollen first part of the duodenum. It is the classic sign of duodenal atresia.

Is duodenal atresia linked to Down syndrome?

Yes. About 30% of babies with duodenal atresia have Down syndrome. When duodenal atresia is suspected on a prenatal ultrasound, parents are usually offered genetic testing.

How is duodenal atresia treated?

The baby's stomach is drained with a tube and fluids are given through a vein. Surgery called a duodenoduodenostomy then joins the bowel above and below the blockage. Feeding starts gradually once the bowel begins working.

What is the long-term outlook for duodenal atresia?

Excellent for most babies. More than 90% survive, and most eat and grow normally. The long-term outlook depends largely on associated conditions, particularly heart defects and Down syndrome.