What is the sphincter of Oddi dysfunction?
Digestion, through which the human body transforms the food we eat into the energy we need, is a complex process. Most people know about the roles that saliva in the mouth and acid in the stomach play in digestion. However, other glands, chemicals, and muscles also play important roles in the process. The liver, the pancreas, and the sphincter of Oddi are among these.
The liver provides a chemical called bile to the digestive process, and the pancreas provides pancreatic juice. These important chemicals flow from the liver and pancreas into the small intestine to help with digestion. The flow of these chemicals is controlled by 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 bouts of severe pain in the abdomen.
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 a dilated bile duct, which might be found by using an ultrasound test.
- In category III dysfunction, there are no clear-cut lab findings or abnormalities, and the only evidence of the dysfunction is the abdominal pain. The pain is believed to be caused by a sudden spasm of the sphincter of Oddi. Type III dysfunction is much more difficult for doctors to diagnose.