Annular pancreas

Signs and symptoms

Early signs of abnormality include polyhydramnios (an excess of amniotic fluid), low birth weight, and feeding intolerance immediately after birth, in particular a tendency to develop epigastric distention associated with non-biliary vomiting (the obstruction is generally above the papilla of Vater, therefore superior to the junction with the bile ducts). Different chromosomal diseases (for example trisomy 21 and, with a minor frequency, trisomy 18 and trisomy 13) are present in about 33% of subjects affected by annular pancreas.

Causes

When ventral pancreatic bud splits and encircles the duodenum leads to a construction in the duodenum

Diagnosis

Postnatal diagnostic procedures include abdominal x-ray and ultrasound, CT scan, and upper GI and small bowel series. Abdominal radiography can show the classic sign of the "double bubble": the presence of air in the stomach and duodenum. Unfortunately, this double-bubble sign is not pathognomonic for annular pancreas, as it can also be observed in other conditions, such as duodenal atresia and intestinal malrotation. Upper GI series may be suggestive of annular pancreas, especially if they show a duodenal narrowing of the second portion of the duodenum and the concomitant dilatation of the proximal duodenum. In some cases it is possible to have signs of inverse peristalsis of the duodenal tract which is proximal to the narrowing caused by the annular pancreas, and the dilatation of the duodenal portion distal to the anomaly. An abdominal CT scan or an MRI allows to highlight the narrowing of the descending duodenal tract and the ring of pancreatic tissue surrounding the duodenum: this ring can be complete or, in patients with an incomplete annular pancreas, extended in a postero-lateral or anterolateral direction with respect to the second part of the duodenum. ERCP or MRCP with secretin allow precise delineation of the anatomical structure and in particular a good visualization of pancreatic ducts, as well as a careful analysis of pancreatic secretion into the duodenum lumen.

Treatment

In neonates, treatment for relief of obstruction usually is bypassing the obstructed segment of duodenum by duodeno-jejunostomy. In adults, due to the minor duodenal mobility, the approach is laparoscopic gastrojejunostomy or duodenojejunostomy.

References

References

1. Lainakis N. (2005). "Annular pancreas in two consecutive siblings: an extremely rare case". European Journal of Pediatric Surgery.
2. Ravitch, MM.. (1975). "The pancreas in infants and children". Surg Clin North Am.
3. (June 2002). "Symptomatic annular pancreas in newborns". Med. Sci. Monit..
4. (December 2010). "Annular pancreas in children: a decade of experience". Eurasian J Med.
5. (2008). "Prenatal diagnosis of annular pancreas: reliability of the double bubble sign with periduodenal hyperechogenic band". Fetal Diagn. Ther..
6. (2015). "Annular pancreas, type I choledochal cyst and malrotation in a low-birth weight newborn: A case report". J Indian Assoc Pediatr Surg.
7. (June 2005). "Double bubble, double trouble". Pediatr. Surg. Int..
8. (April 2004). "Rare clinical presentation mode of intestinal malrotation after neonatal period: Malabsorption-like symptoms due to chronic midgut volvulus". Pediatr Int.
9. (2004). "Coexistence of annular pancreas with carcinoma in the dorsal part of pancreas divisum: diagnostic value of magnetic resonance cholangiopancreatography". Abdom Imaging.
10. (September 2012). "Annular pancreas associated with duodenal obstruction". BMJ Case Rep.
11. (2006). "Annular pancreas in the adult: management with laparoscopic gastrojejunostomy". The American Surgeon.
12. (October 2013). "Annular pancreas concurrent with pancreaticobiliary maljunction presented with symptoms until adult age: case report with comparative data on pediatric cases". BMC Gastroenterol.