Endocrinology: Hyperadrenocorticism Clicker Questions Flashcards
Name the Cushing’s screening test with the highest sensitivity:
A. Low Dose Dexamethasone Suppression (LDDS)
B. AdrenoCorticoTropic Hormone (ACTH) stim test
C. Ultrasound
D. Urine Cortisol Creatinine Ratio (UCCR)
E. Endogenous ACTH
D. Urine Cortisol Creatinine Ratio
This test has 100% sensitivity. We do not use it because it is too sensitive and it’s specificity is too low to be useful as a diagnostic test.
It is a great test to rule out Cushing’s before investigating other diseases.
Which screening test has better sensitivity in screening for Cushing’s?
A. ACTH stimulation test
B. Low Dose Dexamethasone Suppresion Test (LDDST)
B. LDDST
ACTH stim test is about 50% sensitive with adrenal tumor nd no more than 85% sensitive with pituitary -dependent tumors. Whereas the LDDST can be up to 95% sensitive.
Which screening test has the benefit of having very good specificity?
A. UCCR
B. LDDS
C. ACTH stimulation test
D. Oral LDDS with UCCR
C. ACTH Stimulation Test
ACTH stim test is a screening test that also has the benefit of you being very sure that there is Cushing’s present and there are no false positives from chronic disease, stress, etc.
LDDST, despite being very sensitive, is influenced by many chronic diseases. So if you want to do a LDDST, you can not do it the same day of a dental. You need to send the patient home and treat the underlying disease or condition. Once it is healthy, you can perform the LDDST.
The LDDST can NOT be used when there are chronic co-morbid diseases such as diabetes as it will yield a false positive.
Which endocrine test is used to diagnose iatrogenic Cushing’s disease?
A. UCCR
B. LDDST
C. ACTH stim test
D. endogenous [ACTH]
C. ACTH stim test
Adrenal atrophy occurs as a result of exogenous steroids so you want to test adrenal reserve.
You see the dog already has Cushing’s so you don’t want to diagnose Cushing’s. You want to confirm that the Cushing’s is not from an adrenal or pituitary tumor.
The only way to check adrenal reserve is through an ACTH stimulation test
You know that if you give a dog steroid, it will supress the endogenous {ACTH]. You don’t need to test that either.
Which test is not a differentiating test?
A. ACTH stim
B. endogenous [ACTH]
C. LDDST
D. Abdominal ultrasound
E. CT of the head
A. ACTH stim test
A differentiating test can distinguish between a pituitary-dependent and an adrenal-dependent hyperadrenocorticism.
An ACTH stim test is only capable of diagnosing Cushing’s. It will be positive (stimulate beyond the reference range) for both pituitary-dependent and adrenal-dependent HAC.
Endogenous [ACTH] will be extremely low in adrenal-dependent and extremely high in pituitary-dependent (> 50 mg/mL).
LDDST
