Though stones blocking the flow of bile are the most common problem involving the gallbladder and bile ducts, poor bile flow without stones also occurs, resulting in similar symptoms. The term given to these problems is biliary dyskinesia. The diagnosis can be very difficult because the absence of stones tends to lead the physician toward other more common causes for their patient's symptoms(see below).
To understand this problem a little better, we need to review some basic physiology. The gallbladder serves as a blind ended reservoir of bile, a fluid that aids in digestion of food. Bile is produced in the liver and flows into the intestine by moving down the bile duct. When a meal is ingested, a hormone(cholecystokinin or CCK) is released that has a wide range of effects on the flow of bile. The hormone not only causes more bile to be produced and more bile to flow into the bile duct, but it tells the gallbladder to squeeze, releasing its store of bile. CCK also causes the Sphincter of Oddi(see image) to relax, so that the bile spills into the intestine without resistence. One can imagine that if this finely regulated part of digestion malfunctions, symptoms might occur that are very similar to a gallstone blocking flow of bile. Biliary dyskinesia simply means bile is not moving properly. The cause for this disorder is not completely understood.
As stated, the diagnosis of biliary dyskinesia can be quite difficult. Accurate methods to measure bile flow are not readily available. A HIDA scan is a type of gallbladder study that helps detect biliary dyskinesia, essentially measuring how well the gallbladder is working. Though a HIDA scan is helpful when it confirms biliary dyskinesia, a normal study does not rule out biliary dyskinesia.
Other considerations that might cause symptoms similar to biliary dyskinesia include functional intestinal disorders, Irritable Bowel Syndrome(IBS) or ulcer disease. Unfortunately, we have very few tests that can tell us, without question, what's causing certain symptoms.
When studies suggest the gallbladder is not working, removal of gallbladder is frequently offered. Unfortunately, 10-40% of patients have persistent symptoms, indicating there are other problems that remain unaddressed. Even when all studies are normal, gallbladder surgery may be offered because, as stated, the tests we do for these problems are not always accurate. In such situations, up to 80% of patients may see significant improvement in symptoms.
Clearly there is much to learn about biliary dyskinesia. For those patients who choose not to have surgery, or those who fail to respond to gallbladder removal, it is important to have a primary caregiver or specialist who can continue to look for solutions. Methods are being developed to better define other causes of biliary dyskinesia, such as sphincter of Oddi dysfunction(see above image). As well, continued efforts are being made to treat functional intestinal problems such as IBS.