Annular Pancreas

• • Ring of pancreatic tissue from the head of the pancreas surrounds the descending duodenum, leading to obstruction, presenting either in infancy or adulthood

  • Vomitus is bilious if obstruction is distal to the ampulla of Vater

  • Air in the stomach and duodenum proximal to the obstruction on abdominal x-ray (double bubble sign)

Epidemiology

• • Rare congenital condition in which a ring of pancreatic tissue from the head of the pancreas surrounds the descending duodenum

  • The abnormality usually presents in infancy as duodenal obstruction with postprandial vomiting

  • There is bile in the vomitus if the constriction is distal to the entrance of the common bile duct

  • Occasionally, annular pancreas will present in adults with similar symptoms

Symptoms and Signs

• • Upper GI obstruction

  • Vomiting

  • Upper GI bleeding

  • Epigastric pain

Laboratory Findings

• • Hypochloremic metabolic alkalosis

  • Hypokalemia

Imaging Findings

• • Abdominal x-ray: Dilated stomach and proximal duodenum (double bubble sign) and little or no air in the rest of the small bowel

  • Upper GI contrast radiography: Narrowing of the duodenum where it is encircled by the pancreatic head, with proximal dilation

  • ERCP: Pancreatic duct in head of pancreas encircling duodenum

• • Signs and symptoms of upper GI obstruction should prompt radiographic imaging, which may suggest duodenal obstruction

  • Always consider annular pancreas as a cause of duodenal obstruction

  • May cause peptic ulcer disease or chronic pancreatitis in an adult

Rule Out

• • Other causes of duodenal obstruction

  • -Duodenal tumors

    -Pancreatic head masses

    -Duodenal atresia (infant)

• • Abdominal x-ray

  • Upper GI contrast radiography

  • ERCP confirms the diagnosis but is not necessary

When to Admit

• • All symptomatic cases

• • Correction of fluids and electrolytes

  • The obstructed segment should be bypassed by a duodenojejunostomy

  • The obstructing pancreas should not be resected; high risk for pancreatic fistula

Surgery

Indications

• • All cases in children

  • All symptomatic cases in adults

Complications

• • Chronic pancreatitis

  • Peptic ulcer disease

  • Obstruction

  • Bleeding

Prognosis

• • Excellent after surgical bypass of obstruction

References