Pathogenesis of cholesterol gallstones.

The factors leading to cholesterol cholelithiasis are probably multiple. Although the secretion of bile supersaturated with cholesterol seems to be a common feature among all patients who form cholesterol stones, a variety of pathophysiologic events can produce an increase in lithogenicity. Dietary factors, particularly in the grossly obese, lead to an absolute increase in secretion of cholesterol into bile. Occasionally, excessive loss of the bile salt pool, for example with regional ileitis, may decrease the ability of bile salts to solubilize cholesterol. In many other, subtle alterations in the enterohepatic circulation of bile salts may adversely affect solubility by both decreasing the secretion of bile salts and increasing the secretion of cholesterol. Regardless of its cause, supersaturation of bile with cholesterol appears to be a prerequisite for gallstone formation. However, additional factors within the gallbladder, such as increased secretion of glycoprotein, increased absorption of fluids, infection, and stasis, appear to contribute to the formation of macroscopic stones.