Duodenal atresia and annular pancreas - Coggle Diagram
Duodenal atresia and annular pancreas
Duodenal atresia etiology
It has been demonstrated that from the fifth to the tenth week of gestation, the endodermal lining of the duodenum proliferates rapidly, obliterates the lumen, and the duodenum becomes a solid cord.
Later, the duodenal lumen is recanalized and is formed by vacuoles that coalesce.
Duodenal atresia results from the failure of vacuolization and recanalization of the duodenal lumen from its solid cord stage.
The pancreas develops from ventral and dorsal endodermal buds.
Annular pancreas etiology
The ventral bud of the pancreas normally rotates backward and becomes situated close to the posterior and inferior surface of the dorsal bud.
An annular pancreas is thought to result from faulty rotation of the ventral pancreatic bud in its course around the circumference of the duodenum.
With an annular pancreas, the ring of pancreatic tissue encircling the duodenum may itself cause an extrinsic partial obstruction.
More often, a duodenal atresia or stenotic web underlies the annulus and is the actual cause of blockage.
Incidenceof duodenal atresia
It occurs in 1 per 5000 - 10000 live births, affecting boys more commonly than girls
The atretic segment is usually just distal to the ampulla of Vater.
Maternal polyhydramnios on antenatal US
Bilious vomiting and intolerance of attempted feedings
Failure to pass meconium in case of complete obstruction
More than 50% of affected patients with duodenal atresia have associated congenital anomalies.
Complete blood count (CBC), serum electrolytes, and bleeding profile.
Dilated stomach and duodenum, giving the characteristic appearance of a "double bubble sign" (the stomach and the proximal duodenum are air-filled), with no gas beyond the duodenum
In partial duodenal obstruction, a plain film of the abdomen will show a "double bubble'' appearance, but there is usually some air in the distal intestine.
Upper GI Study:
where the diagnosis is suspected but the "double-bubble" sign is not clearly visible
injection of 30 to 60 mL of contrast through the nasogastric tube
Exclusion of Other Anomalies:
Surgical correction of congenital duodenal obstruction is
not an emergency
and should be performed in a semi-elective manner in a stable child.
placement rules out associated esophageal atresia seen in an occasional patient.
It is important to place a peripherally inserted central catheter (
) at the outset as it is needed for parenteral nutrition in the postoperative period.
Open Surgery or Laparoscopic Correction:
Open surgery or laparoscopic correction of congenital duodenal obstruction can be performed.
Once the normal rotation of the bowel is ascertained, the duodenum is mobilized, and the cause and site of obstruction are appraised.
Different techniques for different types of atresia.
is performed in cases of type 2 atresia and with an annular pancreas.
A continuous serosal lining points towards a duodenal web (type 1 atresia) and a
duodenotomy with excision of the web
taking care to avoid injury to the ampulla of Vater is the treatment of choice. The duodenum is closed transversely.
Duodeno-duodenostomy also can be performed in this situation but care should be taken to perform the anastomosis between the correct segments across the web.
may be a preferred technique in cases of a type 3 atresia with a wide gap or if the atresia is in the third or fourth parts of the duodenum.
Laparoscopic repair of congenital duodenal obstruction in experienced hands is safe and gives the same results.
Delayed gastric emptying with consequent delayed feeding are usual short-term complications.
Long-term complications include adhesive bowel obstruction.
Anastomotic narrowing with proximal duodenal dilatation requiring open surgery with tapering or endoscopic balloon dilatation.
Classification of duodenal atresia
Type I (92%)
: There is an obstructing septum
formed from mucosa and submucosa with no defect in the muscularis. The mesentery is intact.
Type II (1%): A short
connects the two blind ends of the duodenum. The mesentery is intact.
Type III (7%): There is no connection between the two blind ends of the duodenum. There is a
Y-shaped mesenteric defect.