Final answer:
TPN can contribute to the formation of gallbladder stones by increasing cholesterol production in the liver. The excess cholesterol can form solid gallstones, which can block the bile duct and cause jaundice.
Step-by-step explanation:
Mechanism of TPN causing gallbladder stones
TPN (Total Parenteral Nutrition) is a method of providing nutrients directly into the bloodstream bypassing the gastrointestinal tract. TPN is high in glucose and can lead to an increased production of cholesterol in the liver. The excess cholesterol can then cause the formation of gallstones in the gallbladder.
Gallstones are almost 100% cholesterol with a small amount of other substances. When cholesterol in the gallbladder precipitates and crystallizes, it can form solid gallstones. These gallstones can block the bile duct, preventing the excretion of bile and causing bile pigments like bilirubin to back up into the liver and bloodstream, resulting in jaundice.
It is important to note that TPN is not the primary cause of gallbladder stones, but it can contribute to their formation in individuals who already have risk factors for gallstone formation.