119b biliary tract disorders Flashcards
cholestasis -
1) what is it?
2) what does it cause?
2) characteristic pathology findings on biopsy
1) failure to form bile –> hyperbilirubinemia
2) jaundice
2) canalicular cholestasis
bile plugs
enterohepatic circulation - what happens to excreted bile salts?
bile salts are almost all reabsorbed - only 5% made de novo
What do ALT/AST indicate?
liver cell death - these are released from hepatocytes when they die (AST is inside mitochondria which is damaged by ethanol)
what does high alkaline phosphatase mean?
bile duct obstruction
does a stone stuck outside of liver affect ALT/AST?
no
what should you look for first in a jaundice patient with high conjugated hyperbilirubinermia?
rule out extrahepatic biliary obstruction via US, CT, MRI, ERCP – if negative then move to intrahepatic cholestasis causes (primary liver diseases)
primary biliary cirrhosis - what does it affect? lab findings?
AMA against microscopic bile canaliculis - inflammation and injury
lab - AMA, high Alkaline Phosphatase and GGT
what does high conjugated hyperbilirubinemia mean?
cholestasis - can extra or intrahepatic;
bile salt function
fat digestion/absorption
regulate transcription of liver genes
cholesterol metabolism
ursodeoxycholic (bile salt) acid therapy - what does it treat? how?
treats cholestatic liver disease and pruritis
makes bile acid pool more soluble and less toxic->
dissolves gallstones
what disease does someone have who has occasionally gets scleral icterus when sick?what does it cause?
Gilbert’s disease - no clinical consequences but only 50% of normal UDP-GT due to TATA box increase; extra metabolic capacity of the liver accommodates normally
how do you get rid of cholesterol in body?
bile salts (50%)
Jaundice in the newborn - what is the danger?
BBB sucks and these kids can’t conjugate bilirubin (UDP-GT low at birth) if premature - bilirubin can go to brain and screw things up
how does alcohol lead to cholestasis?
inflammation downregulates transporters - leads to intrahepatic cholestasis (caused by alcohol and other things)
intrahepatic cholestasis of pregnancy
defect in transporters due to genetics that is only clinically significant except when high estrogen levels –> estrogen downregulates transporters
