gallstone
(gol'stōn‵ 
)
A concretion formed in the gallbladder or bile ducts. Gallstones typically are made either of crystallized cholesterol deposits or calcium crystals ionized with bilirubin. Cholesterol stones are about four times more common than stones containing calcium.
SEE: illus..
SYN: biliary calculus; lithiasis biliaris.Incidence: Gallstones are found in about 15% of men and 30% of women in the U.S. (about 20 million Americans).
Symptoms and Signs: Biliary colic due to either type of gallstone may cause intense pain in the right upper quadrant of the abdomen that may radiate to the right flank, back, or shoulder. The symptoms may occur after a fatty meal and may be associated with nausea or vomiting or fever. Jaundice may be present on physical examination. Gallstones may also be clinically silent.
Diagnosis: Cholesterol stones are nonradiopaque and may on occasion be dissolved by medication. Calcium-containing radiopaque stones are not amenable to chemical dissolution and are therefore visible on plain x-rays of the abdomen.
Treatment: Asymptomatic gallstones are neither removed nor treated. Symptomatic gallstone disease is treated primarily in the U.S. by laparoscopic cholecystectomy, which, when successful, avoids prolonged hospitalization. Drug therapy for gallstones may include the use of ursodiol. Stones found in the extrahepatic bile ducts are treated surgically according to the presentation. Cholecystotomy is reserved for patients too ill to tolerate cholecystectomy, usually as a temporizing procedure. Gallstone lithotripsy is infrequently used because it is technically more complex than laparoscopic cholecystectomy, which is relatively more expensive, labor-intensive, and less effective.
Ursodiol (ursodeoxycholic acid), taken orally, is sometimes effective in treating cholesterol gallstones. Treatment may need to be continued for 1 year. A similar agent, chenodiol, is no longer available because it caused an unacceptable incidence of hepatotoxicity.