Sphincter of Oddi Dysfunction:
What is sphincter of Oddi dysfunction?
The sphincter of Oddi refers to the smooth muscle that surrounds the end portion of the common bile duct and pancreatic duct. This muscle relaxes during a meal to allow bile and pancreatic juice to flow into the intestine. The sphincter of Oddi has three major functions: 1) regulation of bile and pancreatic flow into the duodenum, 2) diversion of hepatic bile into the gallbladder, and 3) the prevention of reflux of duodenal contents into the pancreaticobiliary tract. With the ingestion of a meal, the gallbladder contracts and there is a simultaneous decrease in the resistance in the sphincter of Oddi zone.
The sphincter of Oddi consists of circular and longitudinal smooth muscle fibers surrounding a variable length of the distal bile and pancreatic duct. There are three discrete areas of muscle thickness, or mini sphincters: the sphincter papillae, the sphincter pancreaticus, and the sphincter choledochus
The major physiologic role of the sphincter is the regulation of the flow of bile and pancreatic juice. Cholecystokinin (CCK) and nitrates decrease the resistance offered by the sphincter. Laboratory studies observing the effects of numerous peptides, hormones, and medications on the sphincter have suggested a multifactor control mechanism for the sphincter of Oddi.
There are two types of sphincter of Oddi dysfunction: papillary stenosis and sphincter of Oddi dyskinesia. Papillary stenosis is a fixed anatomic narrowing of the sphincter, typically due to fibrosis. Sphincter of Oddi dyskinesia refers to a variety of manometric abnormalities of the sphincter of Oddi.
Symptoms of sphincter of Oddi dysfunction:
The major presenting symptom in patients with sphincter of Oddi dysfunction is abdominal pain. The pain is characteristically sharp, postprandial, and located in the right upper quadrant or epigastrium. The pain may be associated with nausea and/or vomiting, may last for several hours, and may radiate to the back or shoulder blades. Fever, chills, and jaundice are uncommon symptoms. Patients may also present with acute recurrent pancreatitis
Causes of sphincter of oddi dysfunction:
Sphincter of Oddi dysfunction is a result of anatomic and physiologic abnormalities in the distal choledochus and sphincter. A variable length of the distal choledochus and the pancreatic duct are invested with circular and longitudinal smooth muscle fibers that interdigitate with the extra-ampullary muscle fibers of the duodenal wall to form the sphincter of Oddi. Mini sphincters, or three discrete areas of muscle thickness (sphincter papillae, sphincter pancreaticus, and sphincter choledochus), comprise the sphincter of Oddi.
Treatment & Prevention options:
The goal of treatment is to reduce sphincter of Oddi pressure, thereby improving drainage of biliary and pancreatic secretions into the duodenum. This may be accomplished through medical, endoscopic, or surgical therapy:
Medical therapy for sphincter of Oddi dysfunction is a common treatment approach primarily because it is noninvasive; thereby avoiding the occasionally severe complications associated with surgery (this surgical procedure is known as a sphincterotomy). Because the sphincter of Oddi is composed of smooth muscle, drugs that relax smooth muscle may be effective in patients with sphincter of Oddi dyskinesia and not in patients with papillary stenosis. Agents such as calcium channel blockers and long-acting nitrates have been shown to reduce sphincter of Oddi basal pressure and improve symptoms. There are, however, several negative aspects associated wit medical therapy. Such as, side effects may be seen in up to one-third of patients, a response rate of only about 75% is expected in patients with the spastic-type of sphincter of Oddi and finally, muscle-relaxing agents are not expected to be effective enough.
Endoscopic sphincterotomy is the current standard of therapy for sphincter of Oddi dysfunction. Controlled studies document the short-term and long-term efficacy of endoscopic sphincterotomy with relatively low morbidity and mortality rates. The presence of an elevated basal sphincter pressure appears to predict good benefit from sphincter ablating procedures. In appropriate situations, benefits of endoscopic sphincterotomy are greater than 90%, with good results in long-term follow-up. Because of the high complication rate of pancreatitis after endoscopic sphincterotomy for sphincter of Oddi dysfunction, prophylactic short-term pancreatic stenting is recommended, and often has good results.
Additional patient resources:
- Functions of the gallbladder and bile ducts
- Functions of the pancreas
- Medical Dictionary: Sphinctor of Oddi dysfunction
- Up to Date – Patient Information
- More patient resources
| University of Missouri Health Care | This information is not intended to replace the advice of a doctor. |
