LFTs - amboss Flashcards
ALT is specific to
specific to the cytoplasm of hepatocytes
AST is specific to
present in the liver, heart muscle, and erythrocytes
elevation of ALT and AST
all types of hepatocyte damage, muscle damage, myocardial infarction
significant elevation of AST and ALT
hepatotoxic drugs
some hepatitis subtypes eg. autoimmune, ishchaemic, or acute viral hepatitis
AST/ALT < 1 is called
inflammatory type hepatocellular damage
AST/ALT < 1 can be caused by
uncomplicated viral hepatitis
minor fatty liver disease
extrahepatic cholestasis
AST/ALT > 1 is called
necrotic type hepatocellular damage
AST/ALT >/= 1 can be caused by
alchoholic hepatitis
fulminant, necrotic hepatitis
decompensated cirrhosis
hepatocellular carcinoma, liver mets
muscle damage
myocardial infarction
AST/ALT in alchoholic hepatitis
> 2
AST usually does not exceed 500
AST/ALT in muscle damage
AST is present in skeletal muscle cells more than ALT, so damage to myocytes causes more increase in AST than ALT
cholestasis leads to an increase in
typically leads to an increase in direct (conjugated) bilirubin and induces the production of ALP and GGT
retention of bile salts can also cause hepatocyte damage
fractionating bilirubin
determining total bilirubin and direct bilirubin
can help to differentiate between cholestasis and other causes of hyperbilirubinaemia
cholestasis leads to high direct bilirubin
ALP is found in
isoenzymes found in numerous tissues, inclduing liver, bones, placenta and kidney
GGT is found in
most sensitive for liver and biliary tract
usually the first enzyme to rise after bile duct obstruction
ALP elevation
cholestasis (obstructive or non obstructive)
infiltrative diseases of the liver (malignancies or amyloidosis)
increased osteoblast activity
seminoma
pregnancy (third trimester)
chronic kidney disease
