How is pathophysiology of gall stones?

Genetic factors (LITH gene), hepatic hypersecretion of cholesterol, gallbladder hypomotility, rapid phase transitions of cholesterol, intestinal factors all play a role in cholesterol nucleation and crystallization and forming cholesterol gall stones. As for pigmented stones, abnormalities in bilirubin metabolism and bilirubin precipitation, for black pigmented stones uninfected gallbladders with chronic hemolytic anemia (b-thalassemia, SCA), ineffective erythropoiesis (pernicious anemia), ileal diseases (Crohn's) w/ excess bile salts into large intestine, ileal resections, and liver cirrhosis play a role For Brown pigmented stones, not only gallbladder but also bile duct formation, especially intrahepatic, due to stasis of bile associated with biliary infection (E.coli especially)