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Old 07-19-2012
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Question Steroids and Renin Angiotensin Aldosterone System

ok, so i came across this question in an nbme. therez an old patient with orthostatic hypotension and they start him on fludracortisone. after 5 days, what do changes do u expect to see in the PLASMA RENIN, SERUM K+, and URINARY K+.

Can somebody please explain this? I really dont know what effect the steriod is supposed to have on all this
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Old 07-20-2012
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since the man has hypotension there is less blood comeing to the kidney.
the AFFERENT arteriole releases Prostaglandins to cause vasodilation and increase renal blood flow.

Now steroids inhibit Prostaglandins and therefore case vasoconstriction and as a result there is drop in Renal blood flow.

This is activate Renin and this intern will increase AT-II and Aldosterone.

Aldosterone will cause Na and H2o reabsorption and excretion of K and H ions.

if answer will be ....

Increse Renin, Decrese blood K and increse Urine K .
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sorry for the typo and grammar errors :P
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Old 07-20-2012
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To quite kaplan physio, glucocorticoids cause HTN by:
-Increasing fluid retention, by acting on the mineralocorticoid receptor
-Increased sympathetic receptor sensitivity

http://www.ncbi.nlm.nih.gov/pubmed/21565673

so you have decreased renin, increased K+ loss in urine.
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Quote:
Originally Posted by smanthrav View Post
To quite kaplan physio, glucocorticoids cause HTN by:
-Increasing fluid retention, by acting on the mineralocorticoid receptor
-Increased sympathetic receptor sensitivity

http://www.ncbi.nlm.nih.gov/pubmed/21565673

so you have decreased renin, increased K+ loss in urine.
so is my concept wrong??
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Old 07-20-2012
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Quote:
Originally Posted by numbndumb View Post
ok, so i came across this question in an nbme. therez an old patient with orthostatic hypotension and they start him on fludracortisone. after 5 days, what do changes do u expect to see in the PLASMA RENIN, SERUM K+, and URINARY K+.

Can somebody please explain this? I really dont know what effect the steriod is supposed to have on all this
fludrocortisone has more mineralocorticoid activity....so by increasing Na reabsorption they cause increase in BP---> reduced renin, increased urinary K excretion and reduced K serum levels
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Quote:
Originally Posted by aj23 View Post
so is my concept wrong??
im afraid but yes mate......glucocorticoids have mineralocorticoids like action too....they doesn't significantly effect PG's in kidney
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Old 07-20-2012
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fludrocortisone - mineralocorticoid effect, so sodium retention and potassium excretion.

Serum sodium - high, serum k - low, urine k - high,
plasma renin will be low - since sodium is high and there will be water retention and therefore RAA system will be suppressed.
hope i'm right with the concept.
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Endocrine-, Pharmacology-, Physiology-, Renal-

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