Sphincter of Oddi dysfunction

Sphincter of Oddi dysfunction is a functional disorder in which stenosis or dyskinesia of the sphincter of Oddi obstructs drainage from the common bile duct (CBD).

Epidemiology

The disorder is associated with a history of cholecystectomy, in which case it is also called post-cholecystectomy syndrome. The vast majority of affected patients are women.

Clinical presentation

The disorder presents with biliary-type abdominal pain or recurrent pancreatitis ¹.

Classification

• type I will present with
  • biliary pain
  • elevated liver enzymes (alkaline phosphatase and aspartate aminotransferase (AST) more than twice)
  • dilated common bile duct (>12 mm)
• type II will present with
  • biliary pain
  • either abnormal liver enzymes or dilation of the common bile duct
• type III presents with only biliary pain and no objective criteria ³

Radiographic features

Ultrasound

The CBD is often dilated (>8 mm). In the setting of prior cholecystectomy, this is not specific for sphincter of Oddi dysfunction. However, in the appropriate clinical context, namely biliary pain and normal liver function tests, a dilated bile duct is supportive of the diagnosis ¹.

CT

CT can also demonstrate dilated bile or pancreatic ducts. CT can be used to document recurrent attacks of acute pancreatitis.

MRI

MRCP may be used to exclude choledocholithiasis and other structural abnormalities, as the exclusion of these is required to diagnose biliary sphincter of Oddi dysfunction ¹.

Nuclear medicine

The static images and time-activity curves in a hepatobiliary scintigram (HIDA scan) can be evaluated in a semi-quantitative manner ². With sphincter of Oddi dysfunction, there is increased time to hepatic peak, delayed biliary visualization, delayed clearance of radiotracer from the dilated bile ducts, and prolonged biliary to bowel transit.