Gallbladder Pain

The pain of gallbladder disease almost always has one of two causes - gallstones or cholecystitis. Gallstones are stones that form in the gallbladder (often misspelledgall bladder). They vary in size from a millimeter or two to several centimeters and are made up of cholesterol or pigment. Cholecystitis means inflammation of the gallbladder. Although, cholecystitis is most commonly caused by gallstones, there are other less common causes as well.

Gallstones have a tendency to become lodged in the bile ducts leading from the gallbladder or liver, and into the intestines. When gallstones lodge in the ducts, they give rise to a specific type of pain called biliary colic. The characteristics of biliary colic are very consistent, and it is important to recognize its characteristics because they direct the physician to the most appropriate test to diagnose gallstones, primarily abdominal ultrasonography. In approximately 5% of cases, ultrasonography will fail to show gallstones. In such situations, if the characteristics of biliary colic are typical, physicians will go on to other more advanced tests for diagnosing gallstones, specifically endoscopic ultrasound. Finally, most gallstones do not cause pain, and are frequently found incidentally during abdominal ultrasonography. If the symptoms for which the ultrasonography is being done are not typical of biliary colic, it is unlikely that the symptoms are caused by gallstones. The gallstones can be truly silent. This is important to recognize because surgery to remove the gallstones is unlikely to relieve the symptoms.

When gallstones lodge suddenly in the duct leading from the gallbladder (cystic duct), the duct leading from the liver to the cystic duct (common hepatic duct), or the duct leading from the cystic duct to the intestine (common bile duct), the normal flow of bile from the liver is interrupted. With obstruction of the common hepatic or common bile duct, the backup of bile causes the ducts (and the gallbladder in the latter case) to distend. This distention (stretching) is the cause of the biliary colic. When obstruction of the cystic duct occurs, fluid is secreted into the gallbladder causing it to distend. Again, the distention causes biliary colic. Biliary colic stops when the gallstone unlodges from the duct.

Source: MedicineNet.com
http://www.medicinenet.com/gallbladder_pain/article.htm