UW pigment gallstones Flashcards
what bilirubin is increased in pigment stone formation?
unconjugated bilirubin
due to incr. unconjugated bilirubin what substance is precipitated?
calcium-bilirubinate precipitation
beta-glucuronidase is released by?2
injured hepatocytes and bacteria.
what stones under infection?
brown
what stones under hemolysis?
black
what does beta-glucuronidase?
hydrolyzes bilirubin glucuronides and increases the amount of unconjugated bilirubin
ileal disease, what stones?
black
incr. enterohepatic cycling of bilirubin (ileal disease)?
black
estrogens effect on HMG Co-A reductase?
estrogens upregulate HMG Co-A reductase, which increases cholesterol synthesis
Desmolase (cholesterol side-chain cleavage enzyme) catalyzes the conversion of cholesterol to pregnenolone, which is the first step in the synthesis of steroid hormones.
.
What substance induce formation of black stones?
Black gallstones form due to the supersaturation of bilirubin,
bilirubin precipitate with what to form black stones?
precipitates with calcium to form multiple small calcium bilirubinate stones.
Bilirubin supersaturation occurs through what mechanism?
Increased bilirubin production
Altered enterohepatic circulation of bilirubin
why occurs increased bilirubin production?
chronic hemolysis
what conditions leads to chronic hemolysis?
sickle cell anemia, hereditary spherocytosis, and thalassemia
what bilirubin is increased due to chronic hemolysis disorders?
free bilirubin
whats happens with free bilirubin due to chronic hemolysis?
increased circulating levels of free bilirubin, which is taken up by the liver and excreted into bile
Altered enterohepatic circulation of bilirubin occurs in what condition?
Ileal disease (eg, Crohn disease) or resection allows bile acids, which are normally reabsorbed in the ileum, to spill into the colon. There, bile acids solubilize unconjugated bilirubin, allowing its reabsorption and concentration within the bile
Stasis can occur due to gallbladder denervation. Eg what condiiton?
transection of the nerves that control gallbladder contraction
Cirrhosis can also occasionally promote the formation of what stones?
black
cirrhosis –> black. Why?
impaired bile acid synthesis and hyperbilirubinemia (due to cholestasis).
