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Flashcards in Liver Function Tests Deck (11)
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explain why gynecomastia is seen in patients with chronic cirrhosis

  • liver's ability to degrade testosterone decreases, which leads to increased conversion of testosterone into estrogen by aromatase


describe what serum bilirubin levels are in hepatitis

  • liver conjugated bilirubin with glucuronic acid to form conjugated bilirubin that is excreted into the intestine
  • in patients with hepatitis, serum total, conjugated and unconjugated bilirubin are increased
    • unconjugated increased because damaged liver has lower capacity for uptake and conjugation of bilirubin
    • conjugated bilirubin elevated in hepatitis due to inflammation 


describe serum bilirubin levels in cholestatic disease and how it changes in prolonged cholestsis

  • serum conjugated bilirubin is predominantly elevated
    • urine is darker colored because conjugated bilirubin is being excreted into the urine
  • serum unconjugated bilirubin may also be elevated in prolonged cholestasis, since liver cells become damaged over time


contrast intrahepatic vs extrahepatic cholestasis

  • intra-hepatic cholestasis is observed in viral hepatitis and drug toxicity and chronic cirrhosis
  • extra-hepatic cholestasis is observed in:
    • stone in the common bile duct or gallbladder
    • tumors around the common bile duct or head of pancreas


describe enzyme levels in hepatocellular injury

  • raised ALT levels is more specific for acute liver cell damage compared to raised AST
    • in acute hepatitis, ALT levels >>>> AST levels
  • in long standing alcoholic cirrhosis, AST >>>> ALT (2:1)


which enzymes indicate cholestasis?

  • ALP and GGT


which enzymes are elevated in biliary stasis (intra or extra hepatic cholestasis)?



What does an elevation in ALP with no increase in GGT indicate?

  • bone disease, placental ALP


what does an elevation in GGT and no increase in ALP indicate?

  • only GGT increased is indicative of recent alcohol use or ingestion of drugs that induce GGT synthesis


how does an ultrasound assess the biliary tree?

  • if the biliary tree is dilated, then there is extrahepatic cholestasis
  • if the biliary tree is not dilated, then intrahepatic cholestasis is suspected


explain why there is an increased prothrombin time in patients with cholestasis

  • cholestasis results in impaired absorption of fat soluble vitamins, including vitamin K, due to reduced entry of bile acids into intestine
  • decreased absorption of vtamin K impairs the post-translational carboxylation of vitamin K dependent clotting factors (II, VII, IX, X) resulting in increased prothrombin time