Small Animal Hyperadrenocorticism

Question 1

Which is the most common type of hyperadrenocorticism?

Answer 1

Pituitary dependent. Due to excess ACTH secretion. Results in excess endogenous cortisol secretion.

Question 2

What are common clinical signs associated with hyperadrenocorticism?

Answer 2

Polyuria, with compensatory polydipsia, truncal alopecia. polyphagia with abdominal distension, muscle wasting/weakness

Question 3

What will the serum Chemistry usually show with hyperadrenocorticism?

Answer 3

Hyperglycemia, increased liver enzymes, With ALP being greater than ALT. Hypercholesterolemia, hypertriglyceridemia

Question 4

What will a UA usually show with hyperadrenocorticism?

Answer 4

Dilute urine (USG <1.020). proteinuria, often UIT is present

Question 5

What result of the urine cortisol: creatinine ratio test is consistent with HAC?

Answer 5

UC:CR > RR value= POSSIBLE HAC

Question 6

How do you perform a LDDST?
What result of the Low-dose Dexamethasone suppression test is consistent with HAC?

Answer 6

Administer dex and take a 0 hr blood sample. Take blood at 4 hrs and 8hrs. If the 8 hrs cortisol is > RR= consistent with HAC

Question 7

Can LDDST differentiate pituitary and adrenal dependent?

Answer 7

Yes- If 4 hr cortisol < RR value OR 4hr cortisol is <50% of 0 hr cortisol= pituitary dependent.

Question 8

How do you perform an ACTH stimulation test
What result of the ACTH stimulation test is consistent with HAC?

Answer 8

Administer cosyntropin and take 0 hr blood sample. Then take blood again in 1 hr.
If 1 hr cortisol is > RR= consistent with HAC

Question 9

Can ACTH stim test differentiate pituitary and adrenal dependent?

Answer 9

Yes- if endogenous ACTH concentration is tested. eACTH < RR is adrenal dependent. Lower or normal eACTH is pituitary dependent.

Question 10

What would a pituitary dependent HAC LDDST results look like

Answer 10

4 hr and 8 hr cortisol is > RR value (usually 1)
4 hr and/or 8 hr cortisol <50% of 0-hr cortisol but ios > RR

Question 11

What are the important facts about treating with Trilostane?

Answer 11

Recommended starting dose and frequency is 1-2 mg/kg q12hr. Give with food. and you have to give brand name.

Question 12

Which test is the monitoring test of choice for Trilostane?

Answer 12

ACTH stim test.

Question 13

When should the ACTH stim test be performed after starting Trilostane?

Answer 13

After diagnosis at day 10-14,
again at day 28-30
then after ANY dose changes at day 14.
Once optimal dose is reached @ 3 months, 6 months then q6months.

Question 14

What is the goal of the ACTH stim test to know the dose is working?

Answer 14

Post-ACTH cortisol of 1.5-5.5 with CONTROL of clinical signs.

Question 15

T/F If the 10-14 day post treatment test shows a cortisol of >5.5 the dose should be adjusted?

Answer 15

False- treatment can take up to 30 days to see a complete response at starting dose.
This test is performed to make sure that cortisol levels are not too LOW (<1.5)

Question 16

T/F if post ACTH cortisol is >5.5 but CS are under control the dose should be adjusted anyway.

Answer 16

False- main goal is to control CS so there is no need to adjust dose.

Question 17

What percentage should the dose be adjsuted if the post ACTh cortisol is >5.5 with CS present?

Answer 17

increase dose by 25%.

Question 18

If post ACTH cortisol is between 0.7-1.5 what should be done?

Answer 18

Stop the Trilostane for 5-7 days then restart at a 25-50% dose reduction.

Question 19

If Post ACTH is <0.7 what is the recommendation?

Answer 19

Stop Trilostane and do not restart until CS of HAC return and adrenal function (ACTH stim test) returns to normal

Question 20

What is the cut off of normal vs abnormal on the ACTH stim test

Answer 20

20-22

Question 21

On abdominal US what would you see to help differentiate pituitary and adrenal dependent HAC?

Answer 21

pituitary would have bilaterally symmetrical enlargement of the adrenal glands
Adrenal dependent would have a mass in the affected adrenal gland and the contralateral adrenal gland would be small.

Question 22

T/F a patient comes in with no signs of HAC but the LDDST is consistent with HAC so you should start treatment.

Answer 22

False- need presence of one or more of the common CS and PE findings to dx HAC