A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A previously healthy 37-year-old woman, gravida 3, para 2, at 29 weeks' gestation comes to the physician because of colicky postprandial abdominal pain. Her vital signs are within normal limits. Physical examination shows a uterus consistent in size with a 29-week gestation. Ultrasonography of the abdomen shows multiple 5-mm hyperechoic masses within the gallbladder lumen. Which of the following processes is most likely involved in the pathogenesis of this patient's condition?
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A
Accelerated gallbladder emptyingIncorrect. Accelerated gallbladder emptying would reduce stasis and decrease stone risk; pregnancy actually slows gallbladder emptying.
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B
Increased secretion of bile acidsIncorrect. Increased secretion of bile acids would IMPROVE solubilization of cholesterol; it is reduced (or relatively reduced) bile acids that promote stones.
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C
Overproduction of bilirubinIncorrect. Bilirubin overproduction causes pigment stones (chronic hemolysis), not the cholesterol stones typical of pregnancy.
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D
Increased secretion of cholesterolCorrect. Estrogen-driven hypersecretion of cholesterol into bile (combined with progesterone-induced hypomotility) supersaturates bile and nucleates cholesterol stones during pregnancy.
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E
Decreased reabsorption of bile acids in the terminal ileumIncorrect. Bile acid malabsorption (as in Crohn or ileal resection) predisposes to gallstones by lowering the bile acid pool, but this patient's stone formation is driven by pregnancy-induced cholesterol hypersecretion rather than ileal disease.
↑ Tap an answer to reveal the reasoning
Answer: D. Hyperechoic gallbladder masses with shadowing in a pregnant woman represent cholesterol gallstones, the most common type. Pregnancy is a major risk factor because elevated estrogen increases hepatic HMG-CoA reductase activity and cholesterol secretion into bile, while progesterone causes gallbladder hypomotility and reduced emptying. The combined effect is supersaturation of bile with cholesterol, which then nucleates around mucin and other crystals to form stones.
Classically, gallstones occur in 'fat, female, fertile, forty' patients, all conditions associated with increased cholesterol secretion. Other risk factors include rapid weight loss, total parenteral nutrition, and certain ethnic groups (Native Americans). Pigment stones, in contrast, form from unconjugated bilirubin precipitation and are seen in chronic hemolysis or biliary infection. Symptomatic cholelithiasis in pregnancy is managed conservatively when possible; cholecystectomy is safest in the second trimester if surgery is required.
**Why each option:**
**A.** Accelerated gallbladder emptying would reduce stasis and decrease stone risk; pregnancy actually slows gallbladder emptying.
**B.** Increased secretion of bile acids would IMPROVE solubilization of cholesterol; it is reduced (or relatively reduced) bile acids that promote stones.
**C.** Bilirubin overproduction causes pigment stones (chronic hemolysis), not the cholesterol stones typical of pregnancy.
**D.** Correct. Estrogen-driven hypersecretion of cholesterol into bile (combined with progesterone-induced hypomotility) supersaturates bile and nucleates cholesterol stones during pregnancy.