What is Sphincter of Oddi Dysfunction?
Sphincter of Oddi dysfunction (SOD) is a relatively rare health issue that is often overlooked when doctors are trying to figure out what’s wrong with a patient. However, diagnosing and treating this condition can significantly improve a person’s quality of life. The Sphincter of Oddi is a muscular valve that controls the flow of digestive juices, like bile and pancreatic juice, from the liver and pancreas into the first part of the small intestine. Dysfunction of this valve can cause symptoms similar to gallstone complications like frequent painful attacks in the abdomen, often after the gallbladder has been removed. This can also be associated with an abnormal liver test, inflammation of the pancreas (pancreatitis), or both.
In worse cases, SOD can lead to visible symptoms of blockage of the bile duct, such as yellowing of the skin and eyes (obstructive jaundice), and long-term pancreatitis. Although this is rare, if other severe diseases that show similar symptoms have been ruled out by the doctors, it should be considered whether the Sphincter of Oddi dysfunction is the cause of the patient’s symptoms. Understanding this condition can be crucial for seeking appropriate treatment and managing one’s health better.
What Causes Sphincter of Oddi Dysfunction?
The exact cause of a condition known as sphincter of Oddi dysfunction is not fully understood. To simplify, sphincter of Oddi dysfunction is a broad term that refers to a range of liver and bile duct disorders. Conditions under this term can result from various problems with the sphincter (a ring-like muscle) including muscle spasms, narrowing of the muscle, or its inability to relax properly.
Additionally, this problem can affect either the biliary or pancreatic sphincters or sometimes, both. The biliary sphincter controls the release of bile from the liver, while the pancreatic sphincter controls the release of pancreatic juices. The health issues that arise from this condition reflect the interconnected nature of these organ systems.
Risk Factors and Frequency for Sphincter of Oddi Dysfunction
Sphincter of Oddi dysfunction primarily affects women between the ages of 20 and 50. Although only about 1.5% of the population have this condition, this figure might be an underestimate and the real percentage could be higher. This is because many cases might be going undetected due to lack of testing and difficulty in identifying markers of the condition. Interestingly, in people with recurrent unexplainable pancreatitis and chronic pancreatitis, the occurrence of sphincter of Oddi dysfunction can be as high as 72% and 59% respectively. This suggests that health care providers should be more alert to this condition.
There are several factors that could increase a person’s chances of having sphincter of Oddi dysfunction. These include:
- Having had their gallbladder removed
- Being born without a gallbladder
- Having gallstones
- Prior gallstone removal using sound waves
- Having a liver transplant
- Struggling with alcohol use
- Having an underactive thyroid
- Having irritable bowel syndrome (IBS)
Although these factors seem pretty diverse, all of them can potentially disrupt the functioning of the sphincter or the flow of bile in some way.
Signs and Symptoms of Sphincter of Oddi Dysfunction
People with Sphincter of Oddi Dysfunction (SOD) usually experience discomfort in their upper stomach and right upper side of their body, which often extends to their back and shoulder. This discomfort typically lasts from 30 minutes to several hours before it fades away on its own. Nausea and vomiting are other symptoms that these individuals might experience. Unlike gallbladder pain, these symptoms usually do not happen after meals unless the root cause of the dysfunction is related to the pancreatic duct part of the sphincter. Recurrent or long-lasting pancreatitis might also indicate an underlying issue with the sphincter.
Testing for Sphincter of Oddi Dysfunction
Often, patients with suspected sphincter of Oddi dysfunction undergo abdominal imaging, which includes ultrasounds, CT scans, HIDA scans, among others. However, these tests might not always yield helpful results in identifying this particular condition but can help rule out other serious issues.
The gold standard test for diagnosing sphincter of Oddi dysfunction is endoscopic retrograde cholangiopancreatography (ERCP) with manometry. This technique measures the pressure in the sphincter of Oddi, located where the bile and pancreatic ducts enter the intestine. If the pressure is above 35 to 40 mmHg, it indicates sphincter of Oddi dysfunction. However, it is essential to note that the test does not always positively identify the condition and can miss some patients with apparent symptoms.
Lab tests such as a comprehensive metabolic panel (CMP), amylase, and lipase are also recommended to check for indications of liver or pancreas problems. Another method for diagnosing the condition is a functional exam known as the Nardi test. During this test, drugs are given to contract the bile duct and the sphincter of Oddi, and if sphincter of Oddi dysfunction is responsible for a patient’s symptoms, this test should replicate those symptoms.
Diagnosis also involves evaluation of patients’ symptoms and test results to group them into one of three types of sphincter of Oddi dysfunction. The criteria used for diagnosis include increased levels of liver enzymes (transaminitis), expansion of the common bile duct, and pain related to the bile duct (biliary pain).
The types of sphincter of Oddi dysfunction are:
– Type I SOD: includes all three criteria.
– Type II SOD: includes biliary pain and either transaminitis or common bile duct dilation.
– Type III SOD: includes only biliary pain.
The type of sphincter of Oddi dysfunction a patient is classified with will determine the best treatment plan for them.
Treatment Options for Sphincter of Oddi Dysfunction
The sphincter of Oddi dysfunction treatment focuses on reducing the pressure and resistance of a valve in your digestive system. Noninvasive treatments, or treatments that don’t require surgery or other intrusive procedures, include medications like calcium channel blockers, a type of drug that relaxes and widens blood vessels; tricyclic antidepressants, often used for chronic pain management; glyceryl trinitrate, a drug that relaxes blood vessels; and somatostatin, a hormone that inhibits certain bodily processes. The effectiveness of these medications varies.
For example, in a clinical trial, nifedipine, a type of calcium channel blocker, was associated with decreased pain and fewer symptoms, and patients using it made fewer trips to the emergency department and used less pain medication compared to a placebo. Intriguingly, combining these medications in a treatment plan might yield even better results, with a significant number of patients reporting either complete symptom relief or improvement.
Invasive treatments, or treatments that require entering the body, often include ERCP (Endoscopic Retrograde Cholangiopancreatography) with sphincterotomy, a procedure to cut the sphincter of Oddi to relieve the obstruction. This treatment proved to be highly effective and generally safe, resulting in symptom relief in a majority of patients.
Injections of a drug called botulinum toxin have shown to reduce the tension in the sphincter by about 50%. However, it’s only been mildly successful in easing patient symptoms based on a few cases. Nevertheless, the use of botulinum toxin injections and a small tube called a stent to keep the sphincter open can temporarily relieve symptoms. This provides a way to test if a patient’s symptoms will respond well to a more permanent sphincterotomy.
Those diagnosed with type I and type II sphincter of Oddi dysfunction are usually recommended to undergo ERCP and sphincterotomy. However, for type III, procedural interventions have not proven effective. These patients are usually directed towards other form of medical management, focusing on controlling pain.
What else can Sphincter of Oddi Dysfunction be?
Sphincter of Oddi dysfunction usually comes up as a diagnosis when other possibilities have been ruled out. This is crucial because there are several medical conditions that can cause similar symptoms – pain in the upper stomach or the upper right side of your abdomen. So, it’s important to undertake the right tests to exclude other diseases before concluding that the patient has sphincter of Oddi dysfunction.
Particular attention should be paid to other conditions related to the bile duct, such as gallstones in the bile duct (choledocholithiasis), and a rare type of cancer called cholangiocarcinoma. These conditions become particularly required for inspection if the bile duct appears widened and liver enzymes in the blood are high.
What to expect with Sphincter of Oddi Dysfunction
This condition doesn’t inherently pose a significant health threat, but treating it can improve a person’s quality of life. While anyone suspected of having a Sphincter of Oddi dysfunction, which affects the valve controlling the flow of digestive juices from your pancreas and gallbladder to your intestines, might undergo a procedure called ERCP (Endoscopic Retrograde Cholangiopancreatography) and a potential sphincterotomy (a surgery to open the malfunctioning valve), it’s not always necessary.
Most improvement in symptoms is seen in those categorized as type I and II, especially when an abnormal sphincter manometry (a test that measures the pressure inside the valves) is present. However, even in these cases, symptoms don’t typically disappear entirely, pointing to multiple factors playing a role in causing the pain.
The best way to predict the effectiveness of an intervention for this condition is looking at the Milwaukee classification of Sphincter of Oddi dysfunction, which categorizes patients into types 1, 2, and 3. The categorization is based on patient symptoms, lab results, and imaging findings and gives an idea of how patients might respond to sphincterotomy within this classification.
Possible Complications When Diagnosed with Sphincter of Oddi Dysfunction
The management of the sphincter of Oddi dysfunction, a muscle controlling the flow of digestive juices to the intestine, can bring certain complications. These are mostly similar to those seen with ERCP (Endoscopic Retrograde Cholangiopancreatography) and other endoscopy tests. They can include the rupture of an organ (perforation), health issues related to anesthesia (anesthetic morbidities), and inflammation of the pancreas following the ERCP procedure (post-ERCP pancreatitis).
Possible Complications:
- Perforation or organ rupture
- Health issues related to anesthesia
- Inflammation of the pancreas post-ERCP (post-ERCP pancreatitis)
