Hepatobiliary - bile salts and ammonia

Question 1

What AA does cholesterol conjugate with in dogs and cats? Humans?

Answer 1

Dogs and cats – taurine

Humans – glycine

Question 2

What are most reference values based off of?

Answer 2

12 hour fast

Question 3

What is more sensitive, fasting or post-prandial testing?

Answer 3

Post prandial

Question 4

When is a post prandial sample taken?

Answer 4

2 hours

Question 5

What should we feed the animals we are doing a bile acids test? Why?

Answer 5

Science A/D
1-2 tsp for animals < 10lb
1-2 tbsp for animals > 10lb

Provides uniform gall bladder stimulation, GI motility

Question 6

What would cause a pre prandial value to be higher than a post prandial bile acid value?

Answer 6

Unexpected gall bladder contraction: maybe the animal smelled food being prepared

Question 7

What kind of sample should be taken for a bile salts assay?

Answer 7

serum

Question 8

For what assay do you need to specify taurine measurement?

Answer 8

Radioimmuno assay

Question 9

What type of assay measures total bile salts?

Answer 9

Spectrophotometry

Question 10

What interferes with bile acid tests and ammonia tests?

Answer 10

lipemia and hemolysis

Question 11

What are three ways we can test bile acids?

Answer 11

Fasting
Fasting + post prandial
Post prandial

Question 12

Why would fasting + post prandial provide greater sensitivity?

Answer 12

some affected animals with have normal resting levels.

Question 13

Why would we do a bile acids test? Is this a specific test?

Answer 13

Confirm suspicion of decreased functional mass of the liver

NOT specific for decreased functional mass!

Question 14

What are bile acid salts sensitive for?

Answer 14

Hepatobiliary disease

NOT specific for various types though!

Question 15

What are some conditions that may give abnormal results for bile acids and give you a reason NOT to use bile acid test?

Answer 15

Evidence for significant cholestasis
Evidence for significant hepatocellular injury
+/- significant GI dz

Question 16

What are some aberrant patterns/atypical findings for bile acids?

Answer 16

1. poor reabsorption of BA may cause suppress resting BA in animals that should have increase
2. Post BA </= fasted value – test is not of diagnostic value (retest!)
3. Hemolysis is a negative interferent in the assay

Question 17

What does post-BA > or equal to fasted value suggest?

Answer 17

1. spontaneous gall bladder contraction

2. poor CCK response (didn’t eat food, other)

Question 18

What are three additional dx modalities you can use to differentiate b/w shunt and hepatic insufficiency? These are follow ups taken for both bile acids and ammonia

Answer 18

1. Aspiration cytology and/or biopsy
2. Imaging
3. Surgery

Question 19

Why would we do an ammonia or ammonia tolerance test?

Answer 19

confirm presence of decreased functional mass

Question 20

What tow types of conditions present as decreased functional mass?

Answer 20

1. reduced liver parenchyma

2. vascular shunts

Question 21

What are 3 sample handling considerations for ammonia testing?

Answer 21

1. blood must be drawn into ammonia free heparin
2. blood must be put on ice immediately
3. plasma must be separated from the RBC within 20 minutes

Question 22

When should the ammonia sample be run by?

Answer 22

within 30 minutes (60 max)

if quick frozen – run within 2 days

Question 23

When should you run resting ammonia levels first, before running ATT?

Answer 23

1. debilitated animals
2. those showing CNS symptoms

DO NOT run ATT if resting levels are high!!!

Question 24

When can you run resting ammonia levels at the same time as ATT?

Answer 24

clinical symptoms are not severe

Question 25

How can you administer ammonia chloride solution?

Answer 25

orally – animals may vomit

enema (recommended)

Question 26

What provides greater sensitivity, resting ammonia levels or ATT?

Answer 26

ATT

Question 27

What can cause hyperammonemia unrelated to liver dysfunction?

Answer 27

Urea toxicity in cattle

Question 28

What are normal ATT results in a healthy animal?

Answer 28

Purdue says – similar to or less than resting values. +/- mild increase < 25% of resting

Literature says – 2-2.5 fold increase