gallstone

gallstone A stone of varying size that forms when substances in bile harden. There can be just one large stone, hundreds of tiny stones, or any combination and number. Gallstones can block the normal flow of bile if they lodge in any of the ducts that carry bile from the liver to the small intestine. Bile trapped in these ducts can cause inflammation in the gallbladder, the ducts, or, rarely, the liver. If a gallstone blocks the opening to the pancreatic duct, which opens into the common bile duct, digestive enzymes can become trapped in the pancreas and cause extremely painful inflammation called gallstone pancreatitis. Gallstones may not cause symptoms or may lead to pain for up to several hours in the upper back or under the right shoulder, together with nausea, vomiting, abdominal bloating, or indigestion. There are two types of gallstones: cholesterol stones and pigment stones. Gallstones are most common among women, Native Americans, Mexican Americans, and people who are overweight. Laparoscopic surgery to remove the gallbladder is the most common treatment. Also known as cholelithiasis.