Duodenal atresia

Duodenal atresia


Duodenal atresia arises in about 1 in 5000 pregnancies. Embryologically the duodenum requires to be recanalised, a process which usually occurs by about 10 weeks. Atresias are usually found below the ampulla of Vater involving the second and third parts of the duodenum and may be associated with abnormalities of the bile duct; there may be an annular pancreas. The atresia is complete in 40% to 60% of cases, the space between being filled by pancreas.


Usually the diagnosis is not difficult but interestingly the double bubble is not universally apparent at 20 weeks. Presumably this may be because the duodenal cap may fill later in pregnancy. A careful search for other anomalies must be made, especially markers of trisomy 21. Polyhydramnios is a constant finding and is often the initial reason for the scan.

Differential Diagnosis

Distended gallbladder or choledochal cyst both lie more anterior than the duodenum but can be confused. Gut reduplication cysts or mesenteric cysts may be seen but these are unlikely to cause difficulties and are not usually associated with polyhydramnios. An annular pancreas is found in about 20% of cases and will be associated with other cystic changes in the pancreas.

Sonographic Features

Double bubble appearance in the upper fetal abdomen due to a large stomach and duodenal cap


Other features of aneuploidy may be present

Associated Syndromes

  • Brachmann-de Lange syndrome
  • Diabetic embryopathy
  • Fetal hydantoin syndrome
  • Fryns syndrome
  • Opitz-Frias (G) syndrome
  • Short-rib polydactyly syndrome type 1 (Saldino-Noonan)
  • Thalidomide embryopathy
  • Townes-Brocks syndrome
  • Trisomy 21
  • VATER/VACTERL association


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