Sphincter of Oddi

What is sphincter of Oddi dysfunction?

Digestion, through which the body transforms the food we eat into the energy we need, is a complex process. The liver, the pancreas, and the sphincter of Oddi all play important roles.

The liver provides a chemical called bile to the digestive process, and the pancreas provides pancreatic juice. These chemicals flow into the small intestine to help with digestion. The flow of these chemicals is controlled by a muscle called the sphincter of Oddi.

A sphincter is a muscle (usually round) that can open and close. When it's working properly, the sphincter of Oddi opens to allow bile and pancreatic juice to flow through, and then closes again. However, in a condition called sphincter of Oddi dysfunction, the sphincter muscle does not open when it should. This prevents the bile and pancreatic juice from flowing through, and causes a backup of digestive juices. The backup can cause severe pain in the abdomen.

There are two basic types of sphincter of Oddi dysfunction:

  • Biliary dysfunction (the digestive juices are backing up in the bile ducts from the liver);
  • Pancreatitis (the backup is occurring in the pancreas, and the pancreas is becoming inflamed).

There are also three categories of sphincter of Oddi dysfunction:

  • In categories I and II, doctors can find clear evidence of the dysfunction, such as abnormal blood test results or, with an ultrasound, a dilated (widened) bile duct.
  • In category III dysfunction, there are no clear-cut lab findings or abnormalities, and the only evidence of the dysfunction is the abdominal pain. Type III dysfunction is much more difficult to diagnose. Recent studies suggest that these symptoms may not be due to sphincter of Oddi spasm, and that they do not respond to treatment with endoscopic retrograde cholangiopancreatography (ERCP) and sphincterotomy.

Who is at risk for developing sphincter of Oddi dysfunction?

People who have had their gallbladders removed are most likely to develop sphincter of Oddi dysfunction. The procedure to remove the gallbladder is called cholecystectomy, and sphincter of Oddi dysfunction is often referred to as "post-cholecystectomy syndrome." Middle-aged women also appear to be at increased risk for the condition, although doctors aren't sure why.

What are the symptoms of sphincter of Oddi dysfunction?

The symptoms of sphincter of Oddi dysfunction include:

These symptoms can come and go, and can be mild one time and severe the next.

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