Small Animal Hyperadrenocorticism Flashcards
Which is the most common type of hyperadrenocorticism?
Pituitary dependent. Due to excess ACTH secretion. Results in excess endogenous cortisol secretion.
What are common clinical signs associated with hyperadrenocorticism?
Polyuria, with compensatory polydipsia, truncal alopecia. polyphagia with abdominal distension, muscle wasting/weakness
What will the serum Chemistry usually show with hyperadrenocorticism?
Hyperglycemia, increased liver enzymes, With ALP being greater than ALT. Hypercholesterolemia, hypertriglyceridemia
What will a UA usually show with hyperadrenocorticism?
Dilute urine (USG <1.020). proteinuria, often UIT is present
What result of the urine cortisol: creatinine ratio test is consistent with HAC?
UC:CR > RR value= POSSIBLE HAC
How do you perform a LDDST?
What result of the Low-dose Dexamethasone suppression test is consistent with HAC?
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
Can LDDST differentiate pituitary and adrenal dependent?
Yes- If 4 hr cortisol < RR value OR 4hr cortisol is <50% of 0 hr cortisol= pituitary dependent.
How do you perform an ACTH stimulation test
What result of the ACTH stimulation test is consistent with HAC?
Administer cosyntropin and take 0 hr blood sample. Then take blood again in 1 hr.
If 1 hr cortisol is > RR= consistent with HAC
Can ACTH stim test differentiate pituitary and adrenal dependent?
Yes- if endogenous ACTH concentration is tested. eACTH < RR is adrenal dependent. Lower or normal eACTH is pituitary dependent.
What would a pituitary dependent HAC LDDST results look like
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
What are the important facts about treating with Trilostane?
Recommended starting dose and frequency is 1-2 mg/kg q12hr. Give with food. and you have to give brand name.
Which test is the monitoring test of choice for Trilostane?
ACTH stim test.
When should the ACTH stim test be performed after starting Trilostane?
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.
What is the goal of the ACTH stim test to know the dose is working?
Post-ACTH cortisol of 1.5-5.5 with CONTROL of clinical signs.
T/F If the 10-14 day post treatment test shows a cortisol of >5.5 the dose should be adjusted?
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)
T/F if post ACTH cortisol is >5.5 but CS are under control the dose should be adjusted anyway.
False- main goal is to control CS so there is no need to adjust dose.
What percentage should the dose be adjsuted if the post ACTh cortisol is >5.5 with CS present?
increase dose by 25%.
If post ACTH cortisol is between 0.7-1.5 what should be done?
Stop the Trilostane for 5-7 days then restart at a 25-50% dose reduction.
If Post ACTH is <0.7 what is the recommendation?
Stop Trilostane and do not restart until CS of HAC return and adrenal function (ACTH stim test) returns to normal
What is the cut off of normal vs abnormal on the ACTH stim test
20-22
On abdominal US what would you see to help differentiate pituitary and adrenal dependent HAC?
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.
T/F a patient comes in with no signs of HAC but the LDDST is consistent with HAC so you should start treatment.
False- need presence of one or more of the common CS and PE findings to dx HAC
