L13: Concepts of Liver Disease

Question 1

portal vascular system**

Answer 1

• blood flows from all digestive organs to the liver via portal v.
• liver acts as metabolic filter and removes translocated intestinal bacteria

Question 2

hepatic vascular anatomy

Answer 2

• portal v., hepatic aa., bile duct feed into liver
• hepatic v. feeds into CVC
• biliary system circulates countercurrent to blood supply and eventually heads to intestines
• liver lobule is radially arranged around a central hepatic venule w/ portal triads at the periphery
• portal triad = portal v, hepatic a., bile duct

Question 3

zones in hepatic vascular anatomy

Answer 3

1: periportal region
2: intermediate zone b/w portal triads and central v.
3: around central v.

Question 4

components of acinus

Answer 4

• sinusoids lined by fenestrated endothelium
• Kupffer cells part of reticuloendothelial system (liver’s “immune system”)
• stellate cells provide support

Question 5

anatomy of hepatocyte

Answer 5

• very metabolically active
• tight junctions between
• sinusoids on top and bottom
• bile canuliculi connect to form bile ducts

Question 6

hepatic functions

Answer 6

• carb/lipid/protein/vitamin metabolism
• immunologic functions
• detoxification and excretion of bilirubin, steroids, ammonia, drugs
• synthesis, regulation, enterohepatic circulation of bile acids

Question 7

slide 11

Answer 7

:)

Question 8

Q: what % of liver can be removed before evidence of dysfunction?

Answer 8

A: 75%

Question 9

breed disposition to liver dz

Answer 9

dobies
spaniels
labs
bedlingtons

Question 10

what CS most specific for liver dz?

Answer 10

jaundice

Question 11

low protein ascites indicative of:

Answer 11

portal hypertension

hypoalbuminemia

Question 12

high protein ascites indicative of:

Answer 12

R-sided heart failure
caval syndrome (due to backflow into portal system)

Question 13

general principles of liver dz in cats

Answer 13

• ascites uncommon
• palpate thyroid gland and measure T4
• copper colored iris in 60% of feline shunts

Question 14

what is often 1st sign of liver disorder?**

Answer 14

clinicopathologic abnormalities

-often secondary to other disorder like reactive hepatopathies*

Question 15

do liver enzymes indicate function?

Answer 15

NO

Question 16

liver enzyme indicators of cell damage**

Answer 16

ALT

AST

Question 17

liver enzyme indicators of cholestasis/drugs

Answer 17

ALP

GGT

Question 18

where ALT found?

Answer 18

• cytoplasm

- liver specific*

Question 19

where AST found?

Answer 19

• cytoplasm and mitochondria

- can be in liver, muscle, RBCs

Question 20

greatest increases of ALT/AST seen with:

Answer 20

necrosis

Question 21

T/F: poor correlation b/w magnitude of increase of ALT/AST and severity of disease

Answer 21

T

Question 22

where ALP found?

Answer 22

bone, liver, steroid inducible (dogs only)

-membrane bound

Question 23

why is elevation of ALP significant?

Answer 23

-usually indicates a more chronic problem b/c minor disturbances that cause cholestasis usually don’t cause rise in ALP

Question 24

where GGT found?

Answer 24

mainly liver

-membrane bound

Question 25

ALP/GGT induced by:

Answer 25

- cholestasis | - drugs

Question 26

"Pseudofunction" liver function tests

Answer 26

- bilirubin - albumin - BUN - cholesterol - Glucose

Question 27

"True function" liver function tests

Answer 27

- ammonia | - serum bile acids

Question 28

Q: ALT greatly increased, ALKP mildly increased. Hepatocellular or cholestatic origin?

Answer 28

hepatocellular

Question 29

3 categories of causes for icterus

Answer 29

pre-hepatic hepatic post-hepatic

Question 30

pre-hepatic causes of icterus

Answer 30

-hemolysis (rule out by doing PCV or Hct)

Question 31

hepatic causes of icterus

Answer 31

- hepatitis - hepatic lipidosis - neoplasia - cirrhosis - toxins/drugs - sepsis

Question 32

post-hepatic causes of icterus

Answer 32

``` pancreatitis cholangitis cholecystitis choleliths biliary neoplasia GB mucocele duodenal disease ```

Question 33

bilirubinuria always significant in cats!!**

Answer 33

:)

Question 34

albumin produced by:

Answer 34

liver

Question 35

when is albumin decreased

Answer 35

liver disease, PLE, PLN, effusions, maldig/malab. disease

Question 36

does albumin decrease under anorexia?

Answer 36

barely

Question 37

Blood Urea Nitrogen (BUN) test

Answer 37

- related to ammonia and metabolism | - low BUN suggests dysfyunction such as dec. appetite, low protein diet, diuresis

Question 38

causes of hypoglycemia

Answer 38

- liver dysfx - insulinoma - fasting in puppies - Addison's - etc.

Question 39

when is cholesterol increased? dec?

Answer 39

inc: cholestatic disease dec: liver dysfx (uptake and synthesis in the liver)

Question 40

Blood ammonia test

Answer 40

- ammonia converted to urea in liver - can test fasting ammonia (if high, suggests liver dysfx) - lvls change based on pH of sample, which changes as sample ages!

Question 41

ammonia goes where is PSS?

Answer 41

brain

Question 42

ammonia goes where in hepatitis?

Answer 42

peripheral circulation

Question 43

Serum bile acids test

Answer 43

- give yes or no answer on whether liver functioning normally or not, but doesn't differentiate between TYPE of liver disease - bile acids don't contribute to hepatic encephalopathy - stable in serum - don't need to run if patient icteric (u already know elevated!)

Question 44

slide 32-33

Answer 44

:)

Question 45

what can cause inc. in bile acids

Answer 45

PSS | parenchymal disease

Question 46

additional diagnostics in liver dz

Answer 46

- CBC - Clotting function - Fecal exam to look for GI bleeding - rads - abdominocentesis - U/S - aspiration cytology - biopsy