A 35-year-old primigravida is found to have gallstones at 38 weeks of an uncomplicated pregnancy. Ultrasonography performed one year ago failed to demonstrate any abnormalities. Which of the following pathogenetic components most likely contributed to this patient's condition?
Classically, cholelithiasis (gallstone disease) is most common in those who are "fat, fertile, female, and forty." The gallstones are formed by the aggregation of bile constituents and are categorized as cholesterol stones, pigment stones, or mixed stones.
Pregnancy and the usage of oral contraceptives 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, which causes the bile to become supersaturated with cholesterol. Progesterone reduces bile acid secretion and slows gallbladder emptying. When the gallbladder is hypomotile or there is more cholesterol than bile salts, the cholesterol precipitates into insoluble crystals that eventually form to make gallstones.
(Choices A, B, C, and D) Cholelithiasis is not secondary to water reabsorption from bile or to the hypersecretion of phospholipids, sodium, bile acids, or bilirubin. Moreover, it is the progesterone-induced gallbladder hypomotility - not hypermotility - that increases the likelihood of developing gallstones.
Educational Objective:
Estrogen-induced cholesterol hypersecretion and progesterone-induced gallbladder hypomotility are responsible for the increased incidence of cholelithiasis in women who are pregnant or using oral contraceptives.