Lecture 17 11/7/24 Flashcards
How is hepatic insufficiency seen in terms of carbohydrate metabolism?
hypoglycemia
How is hepatic insufficiency seen in terms of fat metabolism?
hypocholesterolemia
How is hepatic insufficiency seen in terms of protein metabolism?
-hypoalbuminemia
-low urea conc.
What can cause hypoglycemia besides hepatic insufficiency?
-sepsis
-hypoadrenocorticism
-hyperinsulinemia
What can cause hypocholesterolemia besides hepatic insufficiency?
-GI loss
-hypoadrenocorticism
What can cause hypoalbuminemia besides hepatic insufficiency?
-loss
-inflammation
What can cause low urea besides hepatic insufficiency?
-renal loss
-urea cycle enzyme deficiency
What are the characteristics of bile acids?
-component of bile
-excreted in bile and returned to liver via portal circulation
What are the causes of increased bile acids?
-decreased excretion into bile; cholestasis
-decreased clearance from portal blood; portosystemic shunt or hepatic cirrhosis
What are the steps of a bile acids test?
-fast patient for 12 hours
-obtain a pre-prandial blood sample
-feed patient small meal
-wait two hours
-obtain a post-prandial blood sample
What is the interpretation for a bile acids test?
-post-prandial bile acids greater than >20-25 micromol/L has high specificity for hepatocellular disease
What are the caveats to bile acids interpretation?
-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
What are the characteristics of ammonia?
-liver converts ammonia to urea
-decreased conversion of ammonia can result in hyperammonemia
What are the liver-specific causes of decreased urea?
-decreased hepatic functional mass
-impaired blood flow to liver
What are the causes of hyperammonemia outside of the liver?
-intestinal disease/colitis in horses
-urea toxicosis in cattle
What are the characteristics of creatine kinase?
-sensitive and specific biomarker
-short half-life
-mild increases with venipuncture and recumbency
-severe increases seen with rhabdomyolysis
What are the characteristics of skeletal muscle injury?
-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
What are the trends seen when liver is injured, but not muscle?
-increased ALT
-ALT greater than or equal to AST
-increased SDH
-increased AST
-normal/slightly increased CK
What are the trends seen when muscle is injured, but not liver?
-increased ALT
-AST much greater than ALT
-normal SDH
-increased AST
-increased CK
What are the trends seen when both liver and muscle are injured?
-increased ALT
-increased SDH
-increased AST
-normal to increased CK
What are the trends seen when there is hemolysis, but no liver or muscle injury?
-normal ALT
-normal SDH
-increased AST
-normal to increased CK
What are the characteristics of cardiac biomarkers?
-released into blood when heart is damaged or stressed
-support diagnoses of heart failure, myocarditis, and/or cardiomyopathies
-identify patients for further cardiac evaluation
What are the characteristics of cardiac troponin I?
-increases proportionally to myocardial damage
-not specific for primary cardiac disease
-strong negative predictive value
What are the characteristics of B-type natriuretic peptide?
-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
