Do dehydration and high renin in CAH mean I need MC therapy?

Question

Hello doctor,

I am a 34-year-old woman with non-classic lipoid congenital adrenal hyperplasia (CAH). I am currently taking 30 mg of Hydrocortisone daily in divided doses. My aldosterone levels are normal, but my renin levels are elevated. Electrolytes (potassium and sodium) are within normal range, though my BUN is elevated.

Despite this, I have been experiencing frequent episodes of dehydration and have been needing IV fluids once a week. My concern is whether these symptoms mean that I might need Mineralocorticoid (MC) replacement.

Additional medical details:

Height/weight: 5’7”, 138 lbs.
Current medications: Estradiol patch 0.1 mg (twice weekly), Testosterone cypionate 20 mg (weekly), Hydrocortisone 30 mg (daily in divided doses).

Could these ongoing dehydration episodes, along with the elevated renin, be a sign that Mineralocorticoid support is necessary, even though my aldosterone and electrolytes appear normal? Please help.

Thank you in advance.

Answer 1

Hi,

Welcome to icliniq.com.

I read your query and can understand your concern.

From what you have described, it sounds like adding a Mineralocorticoid (MC) replacement, usually a medicine called Fludrocortisone, would be very important. This seems to be the main issue needing attention.

Here is why:

Your renin level is very high, even though aldosterone (the hormone that usually balances salt and water) looks “normal.” In your condition (lipoid CAH (lipoid congenital adrenal hyperplasia), a very rare genetic condition that affects the adrenal glands), “normal” aldosterone is actually too low for how hard your body is trying to compensate.
The renin-angiotensin-aldosterone system (RAAS) is a natural hormone loop that kicks in when your body senses it is losing too much salt or water. Your high renin means this system is working overtime to keep your sodium and potassium numbers looking okay on paper.
The cost of this compensation is that your body is constantly under stress, which explains your frequent dehydration, need for weekly IV fluids, and elevated BUN or blood urea nitrogen (a kidney blood test that rises when you are dried out or your blood volume is too low).

In short, your current Hydrocortisone dose is covering the glucocorticoid (stress hormone) aspect of CAH, but it does not provide you enough Mineralocorticoid support (hormone responsible for regulating salt and water balance). That is why you are still having dehydration and kidney stress.

Starting Fludrocortisone would:

Help your body hold on to salt and water properly.
Lower the high renin levels.
Prevent the constant volume depletion (low blood fluid).
Likely to stop the weekly dehydration crises and bring your BUN back to normal.

Based on your symptoms and lab results, adding a Mineralocorticoid is not just optional; it appears to be a necessary step to stabilize your condition.

I hope this helps.

Kindly revert so I can assist you further.

Thank you.