Clinical Pathology of the Liver Flashcards
Name five functions of the liver
- Protein metabolism
- Carbohydrate metabolism
- Lipid Metabolism
- Storage of glycogen, triglycerides etc.
- Detoxification
- Excretory fuction
What part of the liver is most likely to have hypoxic damage?
Central lobular cells
What are hepatocellular enzymes?
Enzymes released from the cytoplasm of damaged hepatocytes
What is the function of ALP and where is it found?
ALP is an enzyme found in the bloodstream, it helps breakdown proteins in the body
What two genes are needed for the production of ALP?
I-ALP (Intestinal ALP) and tissue non-specific ALP
What is Cholestasis?
Reduced or Stopped Bile Flow
What do hepatocellular enzymes tell us?
They tell us that there is a problem in the liver but can also give us some indication of which part of the liver is affected
What would an increase in ALT, AST, GLDH, SDH, or LDH tell us?
That there is likely an issue with a hepatocyte
Name the special considerations for each animal when it comes to ALP
- Dogs have a high sensitivity for detecting cholestasis, tends to occur before icterus appears
- Cats are typically icteric before the increase in ALP so their diagnostic sensitivity is less optimal than with dogs
- Horses are typically icteric before the increase in ALP
- Cattle have a moderate sensitivity to detection, cholestasis is uncommon
Name the special considerations for each animal when it comes to GGT
- Horses have a better sensitivity for GGT than they do for ALP for detecting cholestasis
- In cattle GGT has a better sensitivity than ALP for detecting cholestasis
- In dogs GGT is parallel with ALP
- in dogs GGT can be indicative for cholestasis but not always increased
What is an increase in ALP indicative of?
Cholestasis
What is liver disease?
Damage or a pathological process affecting the liver
What is hepatic insufficiency?
The liver being unable to function properly
What are some functional indicators of liver disease?
- Decreased Urea
- Increased Billirubin
- Decreased albumin
- increased/ decreased cholesterol
- Increased/ Decreased triglycerides
- Decreased glucose unless cirrhosis
Why may there be increased billirubin in liver disease?
If the liver is not functioning properly then the billirubin will not be properly excreted as bile
Why should you not expose billirubin samples to daylight?
billirubin is sensitive to light
Why is an excess of billirubin indicative of erythrocyte breakdown?
- Once haemoglobin degrades it can be converted to billirubin
When does hyperbilirubinaemia occur?
Occurs when rate of Bu production exceeds rate of Bu uptake by hepatocytes,
» OR rate of Bc formation in hepatocytes exceeds rate of Bc excretion in the bile
What is the difference between conjugated and unconjugated billirubin?
Conjugated billirubin can be excreted in urine whereas unconjugated cannot
What is functional cholestasis and what is it seen in?
When there doesnt appear to be any liver disease or obstruction but there is still an increase in billirubin
- Reported in E.coli and S. intermedius infections in dogs –
Which organ are bile acids released from?
They are released from the gall bladder which contracts in response to feeding
How do you take a bile acid stimulation test?
- Starve the patient for 12 hours
- take a baseline blood sample
- take a second sample 2 hours later
Name 5 hepatocellular liver enzymes
- ALT
- AST
- GLDH
- SDH
- LDH
Name two billiary liver enzymes
- ALP
- GGT- gamma
Name six functional indicators of the liver
- Urea
- Billirubin
- Albumin
- Cholesterol
- Triglycerides
- Glucose
Why is AST not a good indicator of muscle damage in horses?
- Horses already have a high AST baseline
What are the two isoforms of tissue non-specific ALP?
L- ALP (liver ALP)
* B-ALP (bone ALP)
What form of ALP is generally not detected in serum?
intestinal ALP
What is the link between GGT and cholestasis?
increases with cholestasis
Why may high liver enzymes not tell us a lot?
- Liver has a high functional reserve- so it can have extremely high liver enzymes and still function adequately
- or if the liver cirrhoses there may be a loss in the cells that produce liver enzymes (overall loss in liver enzymes)
