Clinical pathology Flashcards
Hepatocellular enzymes small animals
ALT - liver specific
AST - not liver specific - also found in muscles & rbcs
ALP is found in
liver, bone, placenta, intestinal mucosa, renal tubules
Muscle damage
Increased AST (but no increase ALT) Increased creatinine kinase
Increased ALP in cats
Small rise significant following liver damage. Insensitive for choleostasis.
Increased ALP in dogs
Indicates choleostasis
Increased GGT
choleostasis & biliary hyperplasia
(+ due to steroids & anti-convulsants in dogs)
more sensitive marker than ALP in cats.
Hepatic lipidosis in cats
Marked increase ALP + normal GGT
Bile acid production
Produced from cholesterol in hepatocytes.
- conjugated to taurine or lysine
- released into biliary system
- stored in gall bladder
- released into SI - aid fat absorption
Continually circulate between liver and intestine, small amounts lost in faeces
Increased fasting serum bile acid concentration
- disruption of the enterohepatic circuit - cholestasis/bile duct obstruction or PSS
- reduced uptake/excretion by hepatocytes - damage or reduced mass
Bilirubin production
RBCs degraded by macrophages in liver/spleen/BM - unconjugated bilirubin - binds albumin - taken up by hepatocytes - conjugated bilirubin - biliary system - intestines
- converted to faecal pigment by intestinal bacteria
- reabsorbed - excreted in urine
Hyperbilirubinaemia causes
(jaundice)
- pre-hepatic - haemolytic anaemia - also see severe regenerative anaemia.
- hepatic dz - abnormal uptake, conjugation & release
- post-hepatic biliary obstruction
Increased ammonia levels
- hepatic insufficiency
- PSS
- increased production - excessive protein diet, GI bleeding, urea cycle failure
Ammonia processing
produced in intestines as a by product of protein metabolism - detoxified to urea in hepatocytes