duodenal atresia
description
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.
diagnosis
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
polyhydramnios
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
references
- akhtar j, guiney ej congenital duodenal obstruction br j surg 79; 133-135
- athale as, vaishnav tv, jhala pj,vohra p prenatal diagnosis of duodenal atresia by ultrasound indian j pediatr 58; 145-147
- collier d antenatal diagnosis of duodenal atresia by ultrasound; a case report radiography 48; 102-103
- grosfeld jl, rescorla fj duodenal atresia and stenosis; reassessment of treatment and outcome based on antenatal diagnosis, pathological variance and longterm follow up world j surg 17;301-309
- nelson lh, clark ce, fishburne ji, urban rb, penry mf value of serial sonography in the in utero detection of duodenal atresia obstet gynecol 59; 657-660
- miro j, bard h congenital atresia and stenosis of the duodenum : the impact of a prenatal diagnosis am j obstet gynecol 158; 555-559
- petrikovsky bm first trimester diagnosis of duodenal atresia am j obstet gynecol 171; 569-570
- benacerraf br the second trimester fetus with down syndrome: detection using sonographic features ultrasound obstet. gynecol. 7; 147-155