Gallstones

"Fat, Fertile, Female, and Forty"

Types:

Cholesterol, Pigment or Mixed

Cholesterol and mixed stones together comprise 80% of all gallstones in the Western population.

Pregnancy and the usage of OCPs predispose to gallstone formation, with 5-12% of all women developing gallstones during pregnancy.

Estrogenic influence increases cholesterol synthesis by upregulating hepatic HMG-CoA reductase activity --> bile become supersaturated with cholesterol.

Progesterone reduces bile acid secretion and slows gallbladder emptying (hypomotility)

Suppression of cholesterol 7alpha-hydroxylase activity (through fibrate medications) reduces the conversion of cholesterol into bile acids, resulting in an increased concentration of cholesterol within the bile.

Pathogenesis of Cholesterol gallstone

Increased Cholesterol, Decreased bile acids and decreased phosphatidylcholine --> bile becomes supersaturated with cholesterol --> nucleation --> aggregation promoted by mucus hypersecretion, calcium salts, and gallbladder hypomotility --> stone formation

Removal of excess cholesterol from the body occurs via 2 mechanisms: excretion of free cholesterol into bile and conversion of cholesterol into bile acids.

Cholecystitis

Hepatobiliary Iminodiacetic Acid (HIDA)

HIDA scan = the most accurate test

shows delayed emptying of the gallbladder in acute cholecystitis by failure to visualize the GB from isotope accumulation

Histology can reveal Rokitansky-Aschoff sinus formation in chronic cholecystitis