Sphincter of Oddi

 

 

Gallbladder Dysfunction (Biliary Dyskinesia)

Gallstones are the most common cause of gallbladder dysfunction and symptoms such as pain and infection (cholecystitis). However, sometimes the gallbladder can become inflamed and partially obstructed in the absence of stones. The normal gallbladder contracts through muscular activity in response to food, forcing bile through its exit channel (the cystic duct) and into the bile duct for passage into the intestine (through the sphincter of Oddi or the papilla of Vater). . If these movements are not appropriately coordinated, the pressure can rise and result in gallbladder type pain.

In this condition, the gallbladder may appear normal on the standard ultrasound scan; abnormalities are only detected when the gallbladder is stimulated to contract, with food or after an injection of a stimulating hormone (cholecystokinin--CCK). Failure of the gallbladder to contract properly, especially if the patient’s pain is reproduced, is good evidence of gallbladder dysfunction. This can also be investigated by a special type of isotope scan (HIDA scan) during which the behavior of the bile can be watched and the emptying of the gallbladder measured (the ejection fraction). Patients with clearcut symptoms and positive test results respond well to removal of the gallbladder (laparoscopic cholecystectomy).

 

Papillary Stenosis: Sphincter of Oddi Dysfunction



The sphincter of Oddi is the muscular valve surrounding the exit of the bile duct and pancreatic duct into the duodenum , at the papilla of Vater. The sphincter is normally closed, opening only in response to a meal so that digestive juices can enter the duodenum and mix with the food for digestion.

 

Sphincter of Oddi dysfunction and papillary stenosis are conditions which occur when this sphincter (opening) mechanism is disturbed. When the hole is too tight, there is a backup of bile and pancreatic juices. This can cause pain (biliary colic). More prolonged obstruction may result in bile leaking back into the blood stream, resulting in abnormalities of the liver function tests, or even yellow jaundice (discoloration of the eyes and skin). Also, blockage to the pancreatic orifice can cause pancreatic pain or attacks of pancreatitis.

 

Papillary Stenosis can be caused by passage of stones, or scarring after treatments (e.g. endoscopic or surgical sphincterotomy). Papillary stenosis usually results in sufficient backup of bile flow that there is stretching (dilatation) of the bile duct. This can be recognized by scans and various x-rays, including ERCP. Papillary stenosis requires endoscopic or surgical treatment. The hole is enlarged by cutting, to improve drainage. Occasionally it is necessary to do a surgical bypass (choledochoduodenostomy, or Roux-en-Y hepaticojejunostomy) to insure that drainage is effective.

 

Spasm of the Sphincter

This is a more difficult problem. It may be one  manifestation of other muscular spasm problems in different areas of the body (such as the esophagus or intestine--irritable bowel syndrome). However, in some patients, it is the prevailing complaint, and requires focal attention. The pain symptoms are very similar to those caused by bile duct or gallbladder stones. Indeed, sphincter of Oddi dysfunction most frequently occurs in patients who have previously undergone removal of the gallbladder (cholecystectomy). Some patients present with unexplained attacks of acute pancreatitis when the pancreatic sphincter is involved predominantly.

 

Diagnosis of sphincter of Oddi Dysfunction


Initially, tests are aimed to make sure that there are no stones present. Standard ultrasound and CT scans are not very accurate in detecting or excluding bile duct stones; newer techniques such as MRCP and endoscopic ultrasound are more sensitive, but not yet widely available. Most patients are investigated with ERCP. The doctor can examine the drainage hole of the bile duct at the papilla of Vater, and inject dye into the bile duct and pancreatic duct to look for stones and other forms of obstruction. The possibility of sphincter spasm (dysfunction) is considered only when these other conditions have been excluded. Dysfunction can be recognized by a special technique during ERCP, called sphincter of Oddi manometry (SOM). This involves passing a small catheter (tube) into the bile duct and pancreatic duct, to measure the squeeze pressure.

 

Treatment of Sphincter of Oddi Dysfunction

Antispasm medicines are available, but are not very effective. A decision has to be made whether to cut the sphincter (sphincterotomy), during ERCP, or at surgery. When sphincter of Oddi manometry has confirmed that the pressures are high, sphincterotomy gives complete relief in 70-80% of patients; unfortunately, sphincterotomy also carries a significant risk of complications in this context, particularly the provocation of pancreatitis , and the possibility of perforation. Thus, this condition should be approached and managed with considerable care. Patients may warrant referral to specialist centers.

 

Sphincterotomy procedures can sometimes scar after months or years, causing papillary stenosis. Further cutting (repeat sphincterotomy) is sometimes possible, but there are limits; surgical bypass may be necessary.

 

Attempts have been made to treat sphincter of Oddi dysfunction without sphincterotomy-- by placing a temporary plastic splinting tube (stent), or by an injection of botulinum toxin, which paralyzes the sphincter. These treatments are experimental.


5/15/98