A 44-year-old man who has had an extensive small bowel resection for Crohn disease has been on total parenteral nutrition for two years. He presented to the hospital with epigastric and right upper quadrant pain. His vital signs are within normal limits. Physical examination shows mild right upper quadrant tenderness. An ultrasonogram shows several gallstones; an ultrasonogram performed two years ago did not demonstrate gall stones. Which of the following is the most likely cause of his gallstones?

Question

A 44-year-old man who has had an extensive small bowel resection for Crohn disease has been on total parenteral nutrition for two years.  He presented to the hospital with epigastric and right upper quadrant pain.  His vital signs are within normal limits.  Physical examination shows mild right upper quadrant tenderness.  An ultrasonogram shows several gallstones; an ultrasonogram performed two years ago did not demonstrate gall stones.  Which of the following is the most likely cause of his gallstones?

Quizplus · Accepted Answer

Gallbladder stasis is the most likely cause of gallstone formation in this patient. The presence of proteins and fatty acids in the duodenum acts as a stimulus for release of cholecystokinin (CCK), which in turn stimulates the contraction of the gallbladder. In patients on total parenteral nutrition or prolonged fasting, the normal stimulus for CCK release and gallbladder contraction is absent. This leads to biliary stasis and promotes the formation of bile sludge and gallstones. Small-bowel (ileal) resection also contributed to the formation of gallstones in this patient. Decreased enterohepatic circulation of bile acids results in altered hepatic bile composition, which becomes supersaturated with cholesterol and promotes gallstone formation. gallstone formation (Choice A) Estrogen-induced increase in cholesterol secretion is the underlying mechanism for the development of cholesterol gallstones during pregnancy and in women taking oral contraceptives. During pregnancy, estrogen causes an increase in cholesterol secretion and progesterone causes a reduction in bile acid secretion, causing increased cholesterol saturation of bile. Progesterone also slows gallbladder emptying and thus facilitates the formation of cholesterol gallstones during pregnancy. (Choice C) Hypertriglyceridemia can predispose to gallstones in some patients. However, it is unlikely in this patient. (Choice D) Increased enterohepatic recycling of bile acids would not predispose to gallstone formation. Decreased enterohepatic recycling of bile acids, as seen in patients with ileal Crohn disease or ileal resection, can predispose to cholesterol gallstones due to increased concentration of bilirubin conjugates and total calcium in the gallbladder. (Choice E) Increased red blood cell destruction (hemolytic anemia) increases the risk of pigmented gallstones by increasing the amount of heme requiring degradation to bilirubin. Educational objective: Total parenteral nutrition causes gallbladder stasis and predisposes to gallstone formation and bile sludging, both of which may lead to cholecystitis.

A 44-Year-Old Man Who Has Had an Extensive Small Bowel