Sphincter of Oddi Dysfunction - Risk Factors, Symptoms, Diagnosis, and Treatment

Introduction:

The sphincter of Oddi is the smooth muscle lining the ends of the common bile duct and pancreatic duct. It allows the bile juice and pancreatic juice to flow into the intestine during food intake. The sphincter of Oddi dysfunctions is a rare issue, which is often overlooked due to differential diseases. However, its identification and treatment can help to improve the quality of a patient's life. Some of the symptoms are pancreatitis, cholecystectomy, obstructive jaundice, and transaminitis. The treatment of choice for the disorder is the reduction of basal pressure and resistance of the valve. It occurs mostly in females aged between 20 to 50 years. In cases of pancreatitis, the prevalence of sphincter of Oddi dysfunction is as high as approximately 72 %.

Which Diseases Are the Risk Factors for Sphincter of Oddi Dysfunction?

Some of the diseases which can predispose to the sphincter of Oddi dysfunction are -

• Gallbladder Agenesis: A rare condition of congenital absence of gallbladder. Usually asymptomatic but can lead to the sphincter of Oddi dysfunction.

• Cholelithiasis: Also known as gallstones. These are hard deposits of digestive fluids formed in the gallbladder.

• Cholecystectomy: Surgical removal of gallbladder due to severe inflammation or any infection.

• Irritable Bowel Syndrome: Usually a large intestine disorder that causes abdominal pain, gas, bloating, diarrhea or constipation. In some severe cases, it can lead to dysfunction of the sphincter of Oddi.

• Gallstone Lithotripsy: It is a non-surgical treatment procedure that is carried out when gallstones are very small and the gallbladder is functioning.

• Liver Transplantation: The procedure replaces a diseased and damaged liver with a healthy liver from a living donor.

• Hypothyroidism: Deficiency of some crucial thyroid hormones due to mal production of hormones by the thyroid gland.

• Alcohol Use Disorder: It is a chronic disorder characterized by uncontrolled consumption of alcohol.

What Is the Pathophysiology of the Sphincter of Oddi Dysfunction?

The main three functions of the sphincter of Oddi are regulation of bile flow to the duodenum, promotion of gallbladder filling in between the digestive cycles and prevention of reflux to the pancreatic or bile duct. The dysfunction can be due to stenosis or dyskinesia of the sphincter.

• Sphincter Stenosis: Any trauma from the stone in the duct can lead to the narrowing of the sphincter.
• Sphincter Dyskinesia: The alteration in sphincter function due to motility disorders and congenital syndromes.

What Are the Symptoms Observed in the Sphincter of Oddi Dysfunction?

• In most cases, the patient complains of biliary type of pain, which is located in the right upper quadrant and epigastric and radiates to the back and shoulder.

• The pain generally lasts for 30 minutes to a few hours and resolves spontaneously.

• The pain is followed by vomiting and nausea.

• Recurrent pancreatitis can also be observed.

How to Evaluate Sphincter of Oddi Dysfunctions?

• Abdominal imaging such as ultrasound or computed tomography scan does not play many roles in identifying sphincter of Oddi dysfunction but helps to overrule other similar disorders.

• Endoscopic Retrograde Cholangiopancreatography (ERCP) with manometry is the standard gold test for dysfunction of the sphincter of Oddi. The basal sphincter pressure on manometry required for diagnosing the sphincter of Oddi dysfunction is more than 35 mmHg to 40 mmHg.

• The three diagnostic criteria used to classify sphincter of Oddi dysfunction are:

• Common bile duct dilation (greater than 12mm on ERCP and greater than 10mm on ultrasound).

• Transaminitis (greater than two times the upper limit of normal on two or more chances).

• Biliary pain.

Depending on these three categories, the patients are classified as:

Type I Sphincter of Oddi Dysfunction: All the three above categories are present.

Type II Sphincter of Oddi Dysfunction: Biliary pain with any of the other two categories is present.

Type III Sphincter of Oddi Dysfunction: Only biliary pain is observed.

• Laboratory Tests: They are also essential such as comprehensive metabolic panel (CMP), lipase, and amylase, to evaluate hepato- pancreatic dysfunction.

• Nardi Test: This is a functional test used to confirm the diagnosis of sphincter of Oddi dysfunction. This test involves the administration of morphine and neostigmine simultaneously. Morphine causes biliary contraction, whereas neostigmine leads to contraction of the sphincter of Oddi. If the patient is suffering from a sphincter of Oddi dysfunction, the forward pulsion of bile will produce the symptoms.

• Biliary Scintigraphy: A noninvasive procedure performed after stimulation with cholecystokinin. The scoring is done in numerical values, where more than five scores are considered abnormal.

• Secretin Enhanced Magnetic Resonance Cholangiopancreatography (MRCP): Secretin hormone stimulates the secretion of pancreatic juice and hepatic juice. This helps to visualize the pancreaticobiliary ductal anatomy better for MRCP. This technique is preferred as it overrules the complications of ERCP with manometry.

What Is the Treatment of Sphincter of Oddi Dysfunction?

• The main motive for the treatment of dysfunction is the reduction of basal pressure and resistance of the valve.

• Noninvasive Methods: These include tricyclic antidepressants, glyceryl trinitrate, calcium channel blockers, and somatostatin.

• Tricyclic Antidepressants: Amitriptyline, Norpramin, and Doxepin.

• Calcium Channel Blockers: Amlodipine and Felodipine.

• Somatostatin: Octreotide and Lanreotide.

• Invasive Interventions: It includes Endoscopic Retrograde Cholangiopancreatography (ERCP) with sphincterotomy.

Which Diseases Possess Similar Symptoms With Sphincter of Oddi Dysfunction?

As stated earlier, the dysfunction of the sphincter of Oddi is considered a diagnosis of exclusion. Some of the diseases with their symptoms same as that of the sphincter of Oddi dysfunction are:

• Choledocholithiasis - The presence of a minimum of one gallstone in the common bile duct.

• Cholangiocarcinoma - Malignancy affecting the common bile duct.

Conclusion

Sphincter of Oddi dysfunction is characterized by pancreatitis, obstructive jaundice, and pain in the upper quadrant and epigastric region. Some of the common risk factors are gallbladder genesis, cholecystectomy, and irritable bowel syndrome. The treatment options include noninvasive modalities like the use of medications and invasive methods such as Endoscopic Retrograde Cholangiopancreatography (ERCP) with sphincterotomy.