Spincter of Oddi Wiki
Sphincter of Oddi Wiki
Sphincter of Oddi Overview
It would take a lot of imagination to figure out where exactly the sphincter of Oddi is inside your body. Oftentimes, we classify this information as things exclusive for the physicians’ minds. However it would be very useful to familiarize ourselves with them too in order to understand diseases and normal function of our bodies. It would be of great help for you and for your loved ones. Always remember that bodily processes almost always act like dominoes to make things a lot simpler.
Sphincter of Oddi Purpose
The sphincter of Oddi, or the hepatopancreatic ampulla, is a sphincter that serves as the “door” between the common bile duct and the duodenum. The common bile duct, or the CBD in some references, is the passageway of bile from the gallbladder and other secretions from the pancreas. The duodenum is part of the small intestine where most of the breakdown of food occurs after the stomach. When you are not eating, the sphincter of Oddi is “closed” or contracted. It serves as a high-pressure zone of resistance against bile flow. This is to prevent reflux of contents of your duodenum into the common bile duct and pancreatic duct; and to promote filling of the gallbladder. When you eat, sensors inside your duodenum would indicate presence of fat and amino acids which would then stimulate production of the peptide hormone, cholecystokinin or CCK, inside your duodenum. The production of CCK would consequently stimulate the gallbladder to release its contents, which is bile. When the pressure of bile exceeds 100 mm, the sphincter of Oddi “opens” by relaxation releasing bile and other pancreatic juices into the duodenum.
Sphincter of Oddi Anatomy
The sphincter of Oddi contains both longitudinal and circular smooth muscles, surrounding the ampulla of Vater. It is composed of three discrete areas of muscle or “mini” sphincters: the sphincter papillae, sphincter pancreaticus, and the sphincter choledochus. It is usually at the level of the ampulla that the end of the common bile duct and pancreatic duct fuse. However they may be anatomic variations with regard to these structures, where they fuse and on where they empty in the duodenum.
Why the name sphincter of Oddi?
The eponym for, or the man behind the name of, the sphincter of Oddi is Ruggero Oddi, a surgeon in Rome, Italy. He died on 1906. However, the sphincter was already described by Glisson during the 17th century.
Sphincter of Oddi Dysfunction
The relaxation of the sphincter is under neuroendocrine control. Abnormalities in the hormone production, response or in the structure of the sphincter itself may cause a subsequent change in the function of the sphincter of Oddi. With these, there are two types of sphincter of Oddi dysfunction: (1) papillary stenosis and (2) sphincter dyskinesia. The former as mentioned, is more of a structural anatomic abnormality most of the time because of scarring or fibrosis that narrows the sphincter. The latter is related to the neuroendocrine control of the sphincter of Oddi and is usually an intermittent obstruction of the sphincter because of muscle spasm.
Whatever the cause behind the dysfunction of the sphincter of Oddi, the effect and therefore the manifestations are the same. It would fail to relax therefore fail to open and not release the contents of both the common bile duct and pancreatic duct into the duodenum. The dilatation of both ducts would cause spasm and therefore manifest into the most common symptom of abdominal pain or in medical terms, biliary colic.
Sphincter of Oddi Dysfunction Symptoms
Sphincter of Oddi dysfunction or SOD, is a benign disorder. The two identified types of dysfunction are not necessarily mutually exclusive of the other. Other terms for sphincter of Oddi dysfunction are posstcholecystectomy syndrome, biliary spasm, biliary dyssynergia, papillary stenosis and sclerosing papillitis. However these are less precise terms for the dysfunction and are mentioned in order to eliminate confusion once you see them in other medical literature.Other characteristics of the biliary type of pain in sphincter of Oddi dysfunction are its location and duration. It is most usually felt at the upper right quadrant of the abdomen, usually lasts 1 to 5 hours of constant pain or just longer than 30 minutes. It may also radiate to the back or to the shoulder blades. It may also be associated with nausea or vomiting. The pain is severe, dull or boring. The one affected may move around in order to reduce the pain. It is almost always felt after meals, or post prandial, or at night and may awaken you from sleep.
When am I at risk for sphincter of Oddi dysfunction?
Evidence say that SOD occurs spontaneously, but some studies have identified risk groups that are commonly implicated with a dysfunction of the sphincter of Oddi: those who have undergone liver transplant, have acquired immune deficiency syndrome or AIDS, chronic opium users and those with hyperlipidemia. It is also most common in middle aged women, usually at around 75% to 90% of cases (heads up ladies!).
It is most probable to have sphincter of Oddi dysfunction when you experience the biliary-type of pain after a cholecystectomy, the surgical excision of the gallbladder. It is probable when your gallbladder is intact and when you have idiopathic acute recurrent pancreatitis, which is diagnosed by your physician. Its occurrence in AIDS patients is usually possible due to associated protozoal or viral infections.
What is the treatment for sphincter of Oddi dysfunction?
Before your physician can arrive into the diagnosis of sphincter of Oddi dysfunction, you must expect that he or she will make you undergo a number of tests. However, physicians must also make sure that you have enough financial support left for your treatment. The definitive treatment for sphincter of Oddi dysfunction involves the ablation of the sphincter of Oddi. The physician would indicate a sphincterotomy or a sphincteroplasty. The type of surgery would depend on which classification of the sphincter of Oddi dysfunction your condition would fall. A less explored method of treatment for sphincter of Oddi dysfunction is the dietary and medical therapy. In order to reduce stimulation of the sphincter of Oddi by reduction of CCK, a low fat diet may be indicated. Other medical treatments are nifedipine, nitrates, octreotide and antispasmodics however with lacking data on clinical application. You can always ask your friendly physician on the specific effects of whatever medicine he or she indicated for you.