Liver Enzymes Flashcards
Liver specific/hepatocellular leakage enzymes
ALT and AST
Largest elevation of which enzyme is seen with inflammation and necrosis?
ALT
This enzyme increases with muscle damage but not significantly
ALT
Which drugs can cause an elevated ALT?
Corticosteroids, phenobarbital
Which hepatocellular leakage enzyme has a shorter half life?
AST
Which enzyme is more increased with muscle damage?
AST
What other value should you evaluate if AST»_space;> ALT and you are considering muscle damage?
Creatinine kinase
What enzyme is muscle specific?
Creatinine kinase
When will you see an elevated ALP?
Cholestasis, chronic hepatitis, necrosis, neoplasia
This enzyme is relatively non-specific and an be elevated with many hepatic disorders
ALP
Why does ALP have a low specificity in dogs?
Can be high in growing animals, w/bone neoplasia, drugs, endocrinopoathies, or chronically ill patients
What bone isoenzyme of ALP exists?
B-ALP (seen in growing animals and bone neoplasia)
What isoenzyme of ALP exists in dogs but not in cats?
Corticosteroid-induced (C-ALP)
Which dog breed normally has a relatively high ALP compared to other breeds?
Scottish terriers
What GI disease can cause ALP elevations?
IBD
Which enzyme is much more specific at indicating hepatobiliary disease in cats compared to dogs?
ALP
Why is ALP more specific for cats compared to dogs?
Hepatic stores are less than in dogs, short half life
What enzyme is more specific than ALP for cholestatic disease in dogs?
GGT
The liver is the exclusive site of synthesis for which protein?
Albumin
What are processes that cause decreased albumin other than liver problems?
PLE, PLN, acute blood loss, systemic inflammation
Are immunoglobulins made by the liver?
No
Where are immunoglobulins made?
Peripheral blood and LNs
How is BUN affected by liver dysfunction?
Decreased
Why does urea production decrease when the liver is atrophied or severely damaged?
Accumulation of ammonia
When will you see increased ammonia values assoc. w/liver damage?
Liver failure must be relatively advanced
What is unconjugated bilirubin processed from?
Heme
How do you differentiate pre-hepatic vs hepatic vs post-hepatic increases in bilirubin?
HCT, liver function, and cholesterol/cholestatic enzymes
Pre-hepatic hyperbilirubinemia usually has a concurrent _____
Anemia
Post-hepatic hyperbilirubinemia usually has a concurrent elevation in _____
Cholesterol
What does the liver extract from plasma?
Cholesterol
How will cholesterol be affected by decreased liver function?
Hypocholesterolemia
How will a bile duct obstruction affect cholesterol levels?
Elevated (hypercholesterolemia)
How much liver function must be lost before you see a decrease in glucose?
70%
What is the last liver function parameter to drop when you have liver dysfunction/failure?
Glucose
What is a negative prognostic indicator associated with liver dysfuntion?
Hypoglycemia
Which liver enzymes are induced by cholestatsis?
ALP, GGT
Which enzyme is liver specific in cows, sheep, horses, and goats?
SDH
Where is LDH found?
Muscle, heart, liver
What is the best measure of liver function?
BUN
Why might horses develop and increased bilirubin?
Response to fasting
When the liver fails in a horse, what type of crisis is it?
Hemolytic b/c RBCs become more fragile
What are clinical signs of hepatoencephalopathy?
Chronic wt loss, yawning, unaware of surroundings, neuro signs, UTD on vax
What causes hepatoencephalopathy?
Increased ammonia, aromatic AAs and ametacaptans to brain
