Sphincter Of Oddi Dysfunction
Sphincter of Oddi dysfunction is the abnormal relaxation of a muscle ring that controls the release of bile and pancreas into the first part of the small intestine called duodenum. It is a very common cause of upper abdominal pain especially after meals. It is often confused with gallbladder pain. If you have had your gallbladder removed, and still suffer with symptoms of gallbladder pain, it is very likely that you have SOD. See the causes, symptoms, how to diagnose and treat this condition.
A Very Common Cause of Right Upper Abdominal Pain After Meals
What Is Sphincter of Oddi?
The sphincter of Oddi is a very small but power ring of muscle found at the junction where the tube that carry bile from the gallbladder and the tube that brings pancreatic juice from the pancreas meets.
Its function is to regulate the flow of these substances into the first part of the small intestine called the duodenum.
After meals, especially rich or fatty meals, your gallbladder contracts to release bile - that green bitter liquid that helps in breaking down or emulsifying fat in our food to aid its proper digestion. The sphincter of Oddi relaxes to allow the flow of bile into the duodenum. Any abnormality in the muscle affecting the proper relaxation of this muscle or sphincter causes the bile to accumulate and flow back until it becomes stagnant, leading to forceful contraction of the distended tube. The same problem could affect the flow of pancreatic secretions into the duodenum.
This causes severe cramping right upper abdominal pain.
Sphincter of Oddi Dysfunction
The sphincter of Oddi dysfunction occurs if there is stiffness of the muscle
ring at the junction where the common bile duct and the pancreatic duct meets.The resulting back up of secretions from the gallbladder and or pancreas that are unable to flow pass the the sphincter causes severe abdominal pain.
Sphincter of Oddi dysfunction or SOD for short, can occur on its own or after an operation to remove the gallbladder.
There are two types of SOD. They are:
- Papillary stenosis. This is when there is a permanent stiffness and narrowing of the sphincter and
- Papillary Dyskinesia. This occurs when there is abnormality of relaxation off and on, of teh muscles of the sphincter.
Any of the above types of dysfunction could lead to one or both of the following conditions, causing pain:
- Biliary Dysfunction. This is when the sphincter dysfunction leads to a back up of bile in the bile duct, which could lead to distension of the bile duct and forceful contraction of the gallbladder and severe pain. Biliary dysfunction form of SOD can be picked up or diagnosed often by means of ultrasound scan. This type of SOD precipitates a right upper abdominal pain, similar to gallbladder pain.
- Pancreatitis. In this form of sphincter of Oddi dysfunction, the pancreatic duct is more affected by the stiffness in the muscle ring, leading to a back up of the pancreatic juice produced. The back flow of the pancreatic enzymes damages the pancreas, leading to pancreatitis.
Causes of Sphincter Of Oddi Dysfunction
The exact cause or causes of dysfunction of the sphincter of Oddi is not known. However, it is believed that chronic inflammation affecting the ducts and the muscle ring around the ducts could be responsible. Some other doctors believe that intermittent spasm from the muscle could be responsible.
The following are names used to described this same condition:
- Papillary stenosis
- Biliary spasm
Pancreatitis, chronic gall bladder infection, inadvertent injury of the sphincter during surgery, diverticular disease of the duodenum close to the site of the sphincter of Oddi, and tumor affecting the sphincter are all possible causes of SOD.
This condition could occur in anyone and at any age. It is however more common in women in their 30s, 40s and 50s.
Symptoms of sphincter of Oddi dysfunction include:
- Right upper abdominal pain or central abdominal pain after meals
- Colicky or occurring in spams. There may be a continuous pain there with periods of increased exacerbation
- It could happen before or after a gallbladder surgery
- Typically, those with the pain may be thought to have gallstones, and after their gallbladder is removed, they will still suffer with the same pain
- In those who have not had gallbladder surgery, ultrasound scan of their gallbladder may show no stone, despite suffering with very typical gallbladder type pain
- The pain is typically felt around the right breast area and may spread to the right shoulder blade area, into the right arm and neck
- In severe pain, there may be associated nausea and vomiting
- There may be fever with it
- Because this pain tends to occur with or after eating, the sufferer may be scared of eating, leading to weight loss.
So, if you suffer with a right upper abdominal or central upper abdominal pain that tends to come on after eating, and spreads to the right side or back, with associated nausea, it is important you see your doctor to send you for a scan to exclude gallstones. If the scan result comes back and says that everything is fine and there are no stones in your gallbladder, it is almost certain that you may be suffering with SOD or acalculous cholecystitis.
If you, on the other hand has had a surgery to remove your gallbladder but still suffer with the same type of pain that made you have the surgery in the first place, then it is almost certain that you are suffering with sphincter of Oddi dysfunction or postcholecystectomy syndrome. Request that you be sent for test to diagnose or exclude this condition.
The diagnosis of the dysfunction of sphincter of Oddi is usually based on a good description of the pattern of pain by the patient which would lead to your doctor requesting the appropriate test for this condition.
So if you suspect that you have this condition, take the time to write down exactly how the pain comes on, where it is, what you have noticed that makes it worse, does it spread anywhere, and what makes it better.
Also include any other symptoms that you may experience including whether you have chills and rigors, feels nauseated and actually vomits. Are you losing weight - not everyone would have all the symptoms listed above.
The tests for this condition include:
- Ultrasound Scan. This is usually the first test done, and in severe cases, would show a widening or ballooning of the lumen of the common bile duct in the presence or absence of the gallbladder stones. This indicates that there is abnormality of free flow beyond the area that has ballooned.
- HIDA Scan. This will show a reduced flow of bile and the "dye" used in the test, helping to point to an "obstruction" of flow.
- Sphincter of Oddi Manometry. This is the best test available now for the diagnosis of sphincter of Oddi dysfunction. It is done by passing a very tiny wire through the duct of the pancreas or common bile duct and measuring the pressure generated when the sphincter contracts. This test is invasive and can only be done in very specialized places. You will need to be put to sleep for a short time to have this test.
- Other Tests. These include MRCP which is non-invasive, and ERCP which is an invasive test.
- Blood Tests. Apart from the above tests for dysfunction of the sphincter of Oddi, blood tests may also help shed light on what is going on in the liver, common bile duct and pancreas. Blood can be taken for your liver function test or LFT as well as to check for an enzyme that is released by the pancreas called amylase. In SOD, the liver enzyme called SGOT for short may be raised above the normal level and if the pancreas is also affected, the Amylase may also go up than what is expected. If one or both of these enzymes are raised in the presence of a good story that suggest SOD, the diagnosis can be suspected with a very significant amount of certainty. This is even more so if you have had your gallbladder removed and still suffer with gallstone pain.
The SOD has been classified into three diagnostic and patient types, based on the difficulties that may be encountered with diagnosis, which in fact, relates to what is happening in the sphincter. They are:
- Type 1 Sphincter of Oddi Dysfunction. In these group of patient, there come on with pain in the right upper abdomen classical of gallbladder pain, their blood test result would be abnormal, HIDA scan would show abnormal flow of bile, and an ultrasound scan would demonstrate ballooning of the common bile duct or pancreatic duct. In these group of patient the sphincter of Oddi manometry test would be positive in over 86% of them. They are the easiest group of patient with SOD to diagnose.
- Type 2 Sphincter of Oddi Dysfunction. These are the most difficult groups of patients with SOD to diagnose. They only come up with gallbladder pain, but every other test come back normal. It is only in about 28% of this group of patients that the manometry test would be positive.
The take home message here is that if you suspect that you have SOD and all other tests come back normal, if you can afford it and are happy to undergo a manometry test, request for one. It may be the only way of diagnosing your condition. Even if it comes back normal, your doctor may decide that you get treated to see if your symptoms would disappear and get your life back.
Treatment Of Dysfunction Of Sphincter Of Oddi
There are a number of treatment options available for treating SOD. They include:
1. Medical Treatment.
This involves the use of certain types of medications that have the ability to relax the muscle ring or the sphincter of Oddi. Such medicines for sphincter oddi dysfunction include:
- Calcium channel blockers like Diltiazem (also called Cardizem, Dilacor, Tiazac), Amlodipine (also called Norvasc), Felodipine, etc. These medicines are usually used to treat high blood pressure and heart conditions like angina. They work by relaxing the muscles that cause raised blood pressure or tightening of the blood vessels of the heart seen in angina, and also in SOD. The down side with these group of medicines for treating SOD is that they are effective in only a number of patients, and their side effects may be intolerable or some others.
- Nitrates. These are also medicines that work by relaxing tight muscles. They are also used in treating high blood pressure, angina and other heart conditions, as well as SOD. Examples of nitrates include Nicorandil (also called Ikorel), Isosorbide Mononitrate (also called Imdur, Ismo, Monoket) and Isosorbide Dinitrate (Dilatrate, Isordil).
- Botox injection. Just as botox injection is used to relax the muscles on the face to treat wrinkles, if injected directly unto the muscles of the sphincter of Oddi, it relaxes it, bringing about an improvement in the condition. Sphincter of oddi dysfunction botox injection is done by putting you to sleep, and have a tiny endoscope passed through your throat into the duct of the pancreas or common bile duct and then inject a very small amount of botox into the sphincter.
2. Endoscopic Treatment
This involves the use of an endoscope to pass a balloon into the stiff muscle ring and blow it wide, stretching the muscle and opening it up. It is an invasive process, but no cutting is needed.
3. Surgical Treatment
This is the best treatment available. Using an endoscope, a small nick is made on the tight muscle ring, making it more lax and able to allow the free flow of bile and secretions from the pancreas.
- Rehman A,Affronti J,Rao S. Sphincter of Oddi dysfunction: an evidence-based review. Expert review of gastroenterology & hepatology, November 2013, vol./is. 7/8(713-22), 1747-4132
- Nakeeb A. Sphincter of Oddi dysfunction: how is it diagnosed? How is it
classified? How do we treat it medically, endoscopically, and
surgically? Journal of gastrointestinal surgery : official journal of the Society
for Surgery of the Alimentary Tract, September 2013, vol./is.
- Lehman, Glen A., and Stuart Sherman. "Sphincter of Oddi dysfunction." International journal of pancreatology 20, no. 1 (1996): 11-25.
Sphincter of Oddi Dysfunction? Share Your Thoughts!
Do you have upper abdominal pain that tends to be worse after meals and your ultrasound scan result came back normal for gallstones? Or have you had your gall bladder removed and yet still having gall bladder pain? Could this be due to sphincter of Oddi dysfunction? Share your thoughts here!
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