Functional biliary sphincter of Oddi disorder
If all of the above criteria are met, individuals are classified as having a functional biliary sphincter of Oddi disorder, if the testing of pancreatic enzymes (amylase and lipase) is normal.The old Milwaukee classification of biliary sphincter of Oddi dysfunction (SOD) used to divide the condition into three subtypes: but it is no longer in use. Type I included patients with biliary-type abdominal pain, with all of altered liver enzymes on blood testing, dilated biliary ducts on ultrasound or ERCP, and delayed bile clearance on HIDA scan. Type II included patients with biliary-type abdominal pain associated with at least one of the following: altered liver enzymes on blood testing, dilated biliary ducts on imaging tests, and delayed bile clearance on HIDA scan. Biliary-type pain in the absence of any sign of biliary or pancreatic alteration was the so-called Type III biliary SOD. The hypothesis that this pain could be linked to SOD has been studied in a large trial published in JAMA (2014)  where patients were randomized to sphincterotomy or sham surgery. Contrary to expectations, patients who were not subjected to sphincterotomy fared better. Overall, the investigators found that only 23% of the patients who underwent sphincterotomy  improved versus 37% of the control group. The EPISOD trial has substantiated the ineffectiveness of endoscopic sphincterotomy in patients with these symptoms and SOD Type III is no longer considered to be a clinical entity.
Attacks can be precipitated by opioid analgesics, particularly in patients having undergone a cholecystectomy or bariatric surgery. Classification
Functional disorders of the gallbladder, bile duct and pancreas have been defined and classified by the Rome criteria for functional gastrointestinal disorders. The criteria outline three variants of functional disorders of the gallbladder, bile duct and pancreas, termed functional gallbladder disorder, functional biliary sphincter of Oddi disorder and functional pancreatic sphincter of Oddi disorder. All of the following criteria need to be met for as part of the definition of a functional disorder of the gallbladder:
the pain must be located in the upper part of the abdomen and/or the right upper quadrant of the abdomen
episodes of pain must last at least 30 minutes
the symptoms must be recurrent, and occur at differing intervals
the pain must incrementally increase to a "steady level"
the pain must be severe enough the patients daily activities are affected, or that the patient must attend the emergency department
the pain must not be relieved by any of bowel movements, change in posture, or antacids; and,
other structural disorders that could explain the symptoms must be excluded. Functional gallbladder disorder
Individuals are classified as having a functional gallbladder disorder if the above criteria are met, if the gallbladder is present, and if the testing of liver enzymes, conjugated bilirubin, and pancreatic enzymes (amylase and lipase) are normal.