NBME 7-35

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NBME 7-35

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DrVirgo
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08/11/07 - 12:34 PM

A. Adrenal Cortex…
Primary Hyperalsosteronism would cause Na Rentention and K Secretion>
Here the K is HIGH! BUT Na is NORMAL!!
F. Thyroid gland? … Please explain! WHY or Why not.. thanks..

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cirus
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08/11/07 - 12:43 PM

This pt has 2ry Hyperaldosteronism..

The pt has Normal Na & decreased K (typicall of 2ry), in RAS, the blood supply to the kidney will decrease, so leading to false interpretation of hypovolemia by renal centers--> increased Aldosteron d t activation of renin angiot system

the ans is D

drplacebo
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08/11/07 - 07:28 PM

But MRA of abdomen is said to be Normal, does'nt that rule out RAS?

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dr.wad
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08/11/07 - 09:35 PM

agree with u cirus it is D

Justice
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08/11/07 - 10:27 PM

DrVirgo wrote:
Here the K is HIGH! BUT Na is NORMAL!!

DrVirgo, K+ in this case is low...
I also think that this is D...
AS for normal MRI findings and RAS, I am not sure MRI would be very sensitive here...

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vrach
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08/13/07 - 11:36 AM

I think the answer is F - problem in the thyroid gland.

Hypo- and Hyperthyroidism can cause secondary hypertension. This pt isn't on T4 supplimentation after suffering Hashimoto's so she is probably hypothyroid--->decreased functioning of Proximal tubule Na pumps--->increased Na delivery to distal tubule---->Increased sodium resorbtion and potassium secretion in distal tubules---->Normal serum sodium and decreased serum potassium.

If there was a renal artery problem or a problem in the glomeruli, this pt would have lab findings of pre-renal azotemia (elevated BUN/Cr) which is not the case. Besides the MRA is normal.

gr8doc
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08/13/07 - 12:50 PM

A.
The normal sodium is because Na always brings water along with it, so there is dilution. The hallmark here is Hypokalemia.
MRA is the most sensitive for RAS & if it doesn't pick up stenosis, you can safely rule it out.
Will be happy to solve any doubts.

dr_arc
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08/13/07 - 02:30 PM

this is a really nice and confusing question. i picked A when i first saw it looking at the lab parameters of high normal Na and low K.but am also wondering abt E
MRangio being normal comfortably rules out renal artery stenosis though her being a young female makes the diagnosis likely.
aorta fits nowhere in the picture.
thyroid can cause hypertension i guess but wont explain the lab findings of really low K
adrenal meddula - pheochromocytoma would present more dramatically and again not have this profound low K
a pt with hashimotos is more likely by virtue of associations of all thing autoimmune more likely to have AI adrenal failure than anything else.
a tumor of the JG apparatus by secreting renin would probably have the same labs so maybe the answer could be E.
also an adrenal cortical tumor would likely have other steroid related features such as hyperglycemia, maybe a little hirsutism etc.
the vignette seems to have hypertension and hypokalemis as the key features with nothing else to go with it.this scenario would be likely with something that is connected only to the renin angiotensisn aldosterone mech and nothing else. JG celss can do that.
so i think my answer would be E

gr8doc
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08/13/07 - 03:49 PM

JG apparatus is not part of the glomerular system. so it can not be E.
The answer is A. DrVirgo, which one is the wrong answer that you picked ?

hanwin
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08/15/07 - 03:09 PM

#10

A is the correct ans.
This is Conn's.

dr_arc
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08/17/07 - 04:25 PM

#11

hanwin wrote:
A is the correct ans.
This is Conn's.

agree hanwin. i think you are right.

liliaeliz
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08/18/07 - 10:33 AM

#12

a-no because there are not increase Na

b-no pheocromocitome no symp.

c-no symp.coartation

d-roule out MRI

e-no because yuxtaglom(glomerulo +DCT)

f I agree Vrach

dr_arc
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08/19/07 - 04:15 AM

#13

gr8doc wrote:
JG apparatus is not part of the glomerular system. so it can not be E.
The answer is A. DrVirgo, which one is the wrong answer that you picked ?

hey gr8doc. i think i overdiagnosed smiling face

anyway even though the jg apparatus is not anatomically a part of the glomerulus. i thought that for purposes of pathology it would be considered a part of the renal glomerulus.i agree with yor answer.
assumption and overdiagnosis= professional sucide
GL. smiling face

dr19
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11/18/07 - 04:56 PM

#14

correct answer is......????

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