Approach to Incidental Liver Enzyme Elevation

Question 1

hepatocellular injury

Answer 1

ALT and AST

• increase due to hepatocellular necrosis or degeneration
• magnitude of increase indicates the number of effected hepatocytes
• half life of ALT is 2.5 days in dogs and shorter in cats
• persistent increases in ALT mean there is continued hepatocyte injury

Question 2

Cholestasis/Enzyme Induction

Answer 2

ALP and GGT

Question 3

Impaired Liver Function Enzymes

Answer 3

Bilirubin
Albumin
Glucose
Cholesterol
BUN

these are decreased if the liver isn’t functioning

Question 4

if a dog presents with an acute elevation in ALT, is put on liver supplements that cause ALT to go down by 50% a week later, what is likely the general cause?

Answer 4

the dog got into something that caused hepatocellular injury

Question 5

what are ALP isoenzymes and when might they elevate ALP?

Answer 5

1. Liver -> cholestasis -> decreased bile flow and increased ALP
2. Corticosteroid -> cushings, common in dogs but not cats
3. Bone -> YOUNG growing dogs

** the value we get on a chem is a combo of all 3 of these**

Question 6

Bilirubin in relation to liver function

Answer 6

increases with hemolysis, bile tract disease and liver dysfunction

Question 7

Albumin in relation to liver function

Answer 7

Made exclusively in the liver so low albumin indicates significant liver dysfunction as long as loss (through GI or kidneys) has been ruled out

Question 8

Cholesterol in relation to liver function

Answer 8

variable but may decrease

Question 8

Glucose is decreased when >__% of the liver function is lost

Answer 8

75%

Question 9

BUN in relation to liver function

Answer 9

Decrease from PSS or chronic liver disease, r/o low dietary protein intake or starvation

Question 10

__ clotting times suggest significant hepatic disease or factor consumption

Answer 10

prolonged

Question 11

Bile Acids for liver function

Answer 11

Bile acids are the most sensitive liver function test that is readily available for use in small animals. It can be used to screen for loss of hepatic function and PSS.

not indicated if hyperbilirubinemic

>25-30 is abnormal, specificity for liver disease exceeds 90% if >30, 100% if >50

Question 12

common drugs that may cause abnormal liver enzyme elevation

Answer 12

NSAIDs, acetaminophen, anticonvulsants, CBD, antifungal medications, antibiotics (TMS), Azothioprine, Methimazole

Question 13

when should you investigate elevated liver enzymes further?

Answer 13

1. ALT greater than twice the normal RR over several months
2. unexplained liver enzyme elevation persisting over 6-8 weeks (especially ALT)
3. Non hepatic causes have been ruled out

Question 14

Differentials for primary liver disease causing liver enzyme elevation

Answer 14

• idiopathic, inflamm hepatopathy
• copper associated hepatopathy
• infectious hepatopathy
• biliary tract disorders (choleliths, mucocele)
• hepatic vacuolar disorders
• benign hepatic nodular hyperplasia
• hepatic neoplasia
• portal vein hypoplasia

Question 15

whats a liver supplement/protectant and antioxidant?

Answer 15

Denamarin (Sam E and Milk thistle)

Question 16

diagnosis of copper accumulation

Answer 16

liver biopsy

Question 17

treatment of copper accumulation and inflammation

Answer 17

D - penacillamine, liver diet with protein and prednisone

Question 18

chronic hepatitis breed predispositions

Answer 18

• Labs
• american and english cocker spaniel
• Doberman pinscher
• Westies

Question 19

Copper associated hepatitis breed predispositions

Answer 19

• labs
• dalmations
• skye terrier
• doberman pinscher
• west highland white terrier
• bedlington terrier