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Q- A very tan child with a pale mother found to be hypotensive in your clinic. Whats the diagnosis?
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Q- A very tan child with a pale mother found to be hypotensive in your clinic. Whats the diagnosis?
some kind of genetic adrenal insufficiency? Sounds like the kid is having an addisonian crisis. Not sure how the pale mom relates to this.
I think mom is Caucasian so vignette expects the child to be Caucasian too not tan, for that reason child being tan and hypotensive is not normal and I think that's because the child has Cushing's syndrome. That's what I think.
I think mom is Caucasian so vignette expects the child to be Caucasian too not tan, for that reason child being tan and hypotensive is not normal and I think that's because the child has Cushing's syndrome. That's what I think.
Cushing's syndrome involves a hypercortisol state, which would present as hypertension, not hypotension. Remember that cortisol is permissive to autonomic vasoconstriction.
In this case, you have hypotension, pointing towards a possible cortisol deficiency. The tanned skin further points to a primary adrenal deficiency. In this case, the child's adrenals are not responding to ACTH, so they're not making enough aldosterone and cortisol (hence the hypotension). Because the adrenals aren't making aldo and cort, you lose the negative feedback on ACTH, so the body makes more ACTH. The precursor to ACTH is POMC, which also gets made in higher quantities. High POMC means higher levels of all POMC derivatives, including melanin. That's where the tanned skin comes into play.
EDIT: More accurately, high POMC promotes high melanin stimulating hormone (MSH), a direct derivative of POMC. The MSH then goes on to stimulate increased melanin production.
The child does not have cushing's syndrome. Cushing's doesn't cause hyperpigmentation nor does it cause hypotension (infact cushings cause hypo pigmentation and it causes hypertension).
The increase in glucocorticoids causes arterial constriction, which increases blood pressure. It also has a negative feedback loop which decreased ACH secretion, also decreasing melanin formation. http://en.wikipedia.org/wiki/Adrenocorticotropic_hormone
Addisons is the exact opposite, a defect in adrenal output. This causes too much ACTH ->hyperpigmentation. No glucocorticoids or aldosterone ->hypotension.
ignore what I wrote, this is a better explanation. 👍
You are right. I had them switched in my brain and didn't realize it till I rested my brain and thought about it again when I woke up. Thanks for your explanation and correcting me.
The child does not have cushing's syndrome. Cushing's doesn't cause hyperpigmentation nor does it cause hypotension (infact cushings cause hypo pigmentation and it causes hypertension).
The increase in glucocorticoids causes arterial constriction, which increases blood pressure. It also has a negative feedback loop which decreased ACH secretion, also decreasing melanin formation. http://en.wikipedia.org/wiki/Adrenocorticotropic_hormone
Addisons is the exact opposite, a defect in adrenal output. This causes too much ACTH ->hyperpigmentation. No glucocorticoids or aldosterone ->hypotension.
I think actually Cushing's can cause hyperpigmentation if it's a pituitary adenoma--the increased ACTH would be synthesized from preopiomelanocortin along with melanocyte stimulating hormone and Beta-endorphin like withrye mentioned.
Cushing's syndrome mediated by either an adrenal cortical tumor or ectopic ACTH production from small cell lung cancer wouldn't be expected to cause hyperpigmentation.