rida
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Patient has Cushingoid syndrome. Chemistry shows increased ACTH levels, so doc thinks its primary adrenocortical hyperplasia versus adrenal adenoma. Which can help differentiate?
A) Contralateral adrenal atrophy
B) Elevated cortisol levels
C) Normal adrenaline levels
D) Suppression by dexamethasone
E) Tendecny towards hirsutism
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| Idiopathic
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With adrenal cushing's, you shouldnt have ACTH increased...please clarify? An adrenal adenoma would not have incraesed ACTH, for instance (a pituitary adenoma might). What you describe sounds more like Addisons?
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| whereami
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Shouldn't a primary adrenal hyperplasia have decreased, not increased, ACTH due to negative feedback by excessive cortisol?
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| peekay
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suppression by dexamethasone
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| rida
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Idiopathic, i think they are saying the patient is in a Cushing LIKE state, not that he/she has the synderome. do'nt have the answer to this, i do know that the only way to differentiate between these two is with ACTH levels but that is not a choice. My guess was also suppression by dexamethason. Don't know for sure!!
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| shawn333
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rida , it is elmentry , there is a mistake in the question  i was sweating (M3 receptors), with a heavy heart beat , with Beta 2 receptor stimulated . Thinking ,''shawn what are you going to do in the real thing, if you cant answer his question '' then reading Idiopathics reply , made Ach act on the M2 (muscarinic 2 ) ?
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| rida
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Your prob rite shawn, I personally didn't like this question at all, thats why i posted it here.
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| Idiopathic
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"rida" wrote:
Idiopathic, i think they are saying the patient is in a Cushing LIKE state, not that he/she has the synderome. do'nt have the answer to this, i do know that the only way to differentiate between these two is with ACTH levels but that is not a choice. My guess was also suppression by dexamethason. Don't know for sure!!
Someone who is Cushingoid will first have a 24-hour serum cortisol run to determine Cushing status. then a low-dose dexamethasone suppression test will be done. If ACTH is not suppressed, then you know the Cushing's is originating from outside the adrenal. If ACTH is suppressed with high-dose dex test (next step), then the Dx is pituitary adenoma, if not suppressed, then an ectopic tumor is responsible (i.e. lung CA). Hope this helps. ACTH will always be decreased in a case of either primary adrenal hyperplasia or adrenal adenoma, assuming a Dx of Cushings.
The answer should be the Dexamethasone suppression test, given that you know the Px has Cushings.
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| rida
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Thanx idiopathic!!
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| hiwa
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It is obviously not Dexamethasone suppression test,
As the pathology of High ACTH is ectopic and u dont get any suppression by giving Dexamethasone, as the ectoic source has no specialised receptors for cortisone's negative feed back on ACTH.
Apparenly ,B,C,E are irrelevant,
the only explanation for A is COMPENSATORY hyperplasia as a response to atrophy of the contralateral side,
Not very good Q because we are not dealing with the primary problem, Because the primary cause is in the Ectopic ACTH secreting cells,
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| Idiopathic
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"hiwa" wrote:
It is obviously not Dexamethasone suppression test,
As the pathology of High ACTH is ectopic and u dont get any suppression by giving Dexamethasone, as the ectoic source has no specialised receptors for cortisone's negative feed back on ACTH.
Not true. I primary pituitary adenoma (functioning) will be suppressed by high-dose DEX. If not, then you can rule in ectopic ACTH. That is the standard.
I will agree that something about the question is bad. Do they want you to diagnose Cushing's? I am just wondering if, instead of adrenal adenoma (very rarely a cause of Cushing's), they meant it to say pituitary adenoma?
Otherwise, given the nature of an adrenal adenoma, the contralateral side will be atrophied, but ACTH levels would be down anyway in taht case, so...
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| rida
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I found the answer to this question today guys and it says its A.......I really don't like this question.
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| Idiopathic
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Yes, that looks right. I googled 'adrenal adenoma' and it said contralateral atrophy may be seen...but I still cant understand why plasma ACTH is increased.
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| hiwa
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Please read my explanation, because ectopic ACTH not responding to negative feedback,
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| hiwa
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I said ectopic ACTH will not be suppressed, not the primary as explined
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