Physical and metabolic factors in gallstone pathogenesis

Gallstones are divided into three major types-cholesterol, black pigment, a nd brown pigment-depending on their composition, and hence, on their pathog enesis. Gallstones form as the culmination of a complex series of events th at begin when insoluble lipids and inorganic salts secreted by the liver ar e not solubilized normally by the detergent properties of bile salts. This occurs when metabolic events produce bile that contains excess amounts of e ither cholesterol or bilirubin, both of which are relatively insoluble in a queous solution. Additionally, physical factors must allow rapid nucleation within the residence time of bile in the biliary tree. This article discus ses metabolic factors underlying the secretion of supersaturated bile, and physical factors allowing the solubilization and precipitation of the bilia ry lipids and calcium salts that constitute gallstones.