Sphincter of Oddi dysfunction is where a structural stenosis or dyskinesia of the sphincter of Oddi obstructs drainage from the common bile duct (CBD).
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Terminology
This disorder is also known as post-cholecystectomy syndrome and suspected functional biliary sphincter disorder 1,4.
Epidemiology
The vast majority of affected patients are women.
Clinical presentation
The disorder presents with biliary-type abdominal pain or recurrent pancreatitis 1,6. It is most commonly diagnosed post-cholecystectomy for cholelithiasis or functional gallbladder disorder with persistent or worsening pain 1,6. It can be diagnosed without a prior cholecystectomy 1,6,7 but there is a very small evidence base for this 1.
Classification
The Milwaukee classification attempts to provide an anatomical basis to the clinical presentation 3,5 but was recommended to be abandoned by the Rome IV consensus (c.2016) 1 although remains in current use (c.2023) 7.
Milwaukee classification
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type I
biliary pain
elevated liver enzyme: alkaline phosphatase and aspartate aminotransferase more than twice normal
dilated CBD: >12 mm
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type II
biliary pain
either abnormal liver enzymes or dilated CBD
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type III
biliary pain
no objective criteria
Rome IV consensus
According to the Rome IV consensus, Sphincter of Oddi dysfunction is considered in patients with persistent biliary pain post-cholecystctomy with two conditions defined 1:
Sphincter of Oddi stenosis
corresponds to Milwaukee type 1
benefit from sphincterotomy
Suspected functional biliary sphincter disorder
corresponds to Milwaukee type 2 and incorporates post-cholecystectomy syndrome
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diagnosis is based on the following three criteria being met with additional criteria providing further support of the diagnosis
Rome IV criteria for biliary pain
elevated liver enzymes or dilated bile duct, but not both
absence of bile duct stones or other structural abnormalities
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supportive criteria
abnormal spinchter of Oddi manometry
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.