Lecture 17 11/7/24

Question 1

How is hepatic insufficiency seen in terms of carbohydrate metabolism?

Answer 1

hypoglycemia

Question 2

How is hepatic insufficiency seen in terms of fat metabolism?

Answer 2

hypocholesterolemia

Question 3

How is hepatic insufficiency seen in terms of protein metabolism?

Answer 3

-hypoalbuminemia
-low urea conc.

Question 4

What can cause hypoglycemia besides hepatic insufficiency?

Answer 4

-sepsis
-hypoadrenocorticism
-hyperinsulinemia

Question 5

What can cause hypocholesterolemia besides hepatic insufficiency?

Answer 5

-GI loss
-hypoadrenocorticism

Question 6

What can cause hypoalbuminemia besides hepatic insufficiency?

Answer 6

-loss
-inflammation

Question 7

What can cause low urea besides hepatic insufficiency?

Answer 7

-renal loss
-urea cycle enzyme deficiency

Question 8

What are the characteristics of bile acids?

Answer 8

-component of bile
-excreted in bile and returned to liver via portal circulation

Question 9

What are the causes of increased bile acids?

Answer 9

-decreased excretion into bile; cholestasis
-decreased clearance from portal blood; portosystemic shunt or hepatic cirrhosis

Question 10

What are the steps of a bile acids test?

Answer 10

-fast patient for 12 hours
-obtain a pre-prandial blood sample
-feed patient small meal
-wait two hours
-obtain a post-prandial blood sample

Question 11

What is the interpretation for a bile acids test?

Answer 11

-post-prandial bile acids greater than >20-25 micromol/L has high specificity for hepatocellular disease

Question 12

What are the caveats to bile acids interpretation?

Answer 12

-cholestasis causes increased bile acids
-spontaneous gall bladder contraction can increase pre-prandial bile acids
-intestinal disease causes decreased bile acids
-cannot interpret results when pre-prandial bile acids is higher than post-prandial bile acids

Question 13

What are the characteristics of ammonia?

Answer 13

-liver converts ammonia to urea
-decreased conversion of ammonia can result in hyperammonemia

Question 14

What are the liver-specific causes of decreased urea?

Answer 14

-decreased hepatic functional mass
-impaired blood flow to liver

Question 15

What are the causes of hyperammonemia outside of the liver?

Answer 15

-intestinal disease/colitis in horses
-urea toxicosis in cattle

Question 16

What are the characteristics of creatine kinase?

Answer 16

-sensitive and specific biomarker
-short half-life
-mild increases with venipuncture and recumbency
-severe increases seen with rhabdomyolysis

Question 17

What are the characteristics of skeletal muscle injury?

Answer 17

-creatine kinase is main biomarker
-myoglobinuria is supporting evidence
-AST can be derived from skeletal muscle in severe injury; evaluate CK with hepatocellular injury markers

Question 18

What are the trends seen when liver is injured, but not muscle?

Answer 18

-increased ALT
-ALT greater than or equal to AST
-increased SDH
-increased AST
-normal/slightly increased CK

Question 19

What are the trends seen when muscle is injured, but not liver?

Answer 19

-increased ALT
-AST much greater than ALT
-normal SDH
-increased AST
-increased CK

Question 20

What are the trends seen when both liver and muscle are injured?

Answer 20

-increased ALT
-increased SDH
-increased AST
-normal to increased CK

Question 21

What are the trends seen when there is hemolysis, but no liver or muscle injury?

Answer 21

-normal ALT
-normal SDH
-increased AST
-normal to increased CK

Question 22

What are the characteristics of cardiac biomarkers?

Answer 22

-released into blood when heart is damaged or stressed
-support diagnoses of heart failure, myocarditis, and/or cardiomyopathies
-identify patients for further cardiac evaluation

Question 23

What are the characteristics of cardiac troponin I?

Answer 23

-increases proportionally to myocardial damage
-not specific for primary cardiac disease
-strong negative predictive value

Question 24

What are the characteristics of B-type natriuretic peptide?

Answer 24

-useful to differentiate cardiac and non-cardiac causes of resp. distress
-higher conc. seen with congestive heart failure
-used to screen cats for HCM prior to anesthesia