Urine Sodium Test for Hypovolemia?

Ema

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It sounds like a simple 24 hr urine sodium test may be an easy marker for hypovolemia...I recently tested mine and it came back <20.

"With hypovolemia, the urine sodium typically measures less than 25 mEq/L."

https://emedicine.medscape.com/article/242166-workup?src=soc_fb_share

According to this article, "A 24-hour urine sodium is a simple and helpful test that provides documentation that the patient is taking sufficient fluids and sodium. The goal is a volume of 1,500– 2,500 mL and sodium excretion of 170 mmol/24 hours."

Anyone else ever done a urine sodium?
 

ryan31337

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Hi @Ema,

My POTS cardiologist quotes the same research. Its apparently quite contentious as a marker for hypovolemia in POTS but perhaps better than nothing.

What do your results say exactly as you could be comparing urine sodium with expected 24hr urine sodium output.

I had a Urine sodium value of 28 mmol/L (directly equivalent to mEq/L I believe).

On the same test I had a 24 hour urine sodium output of 109 mmol/24Hr (normal range 40 - 220). Volume was measured at 3.9L.

My cardiologist came back and said I needed to approach 170 mmol/24Hr. I already take electrolyte powders 3x a day and add salt to all my food, so I probably need some salt tablets...

Ryan
 

ryan31337

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If you want to look a bit more into potential causes another blood test that may be useful is Aldosterone.

Aldosterone is a hormone that conserves salt, mine was out of range low on testing. Because of that I was booked in for an ACTH Stim test + repeat aldosterone test under suspicion of isolated mineralocorticoid deficiency, but this time round everything worked normally... the fun world of POTS...
 

Ema

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Hi @Ema,

What do your results say exactly as you could be comparing urine sodium with expected 24hr urine sodium output.

I had a Urine sodium value of 28 mmol/L (directly equivalent to mEq/L I believe).

Ryan
The test was a 24 hr urine sodium.

It actually says, "unable to calculate because urine sodium is <20." That's it.

I have mild diabetes insipidus, apparently, and I wonder if the high urine volume (about 5L) was the problem. I couldn't get any more information about the result from the lab or my doctor, unfortunately.

For adults, normal urine sodium values are generally 20 mEq/L in a random urine sample and 40 to 220 mEq/L per day (mEq/L/day). Your result depends on how much fluid and salt you take in. The examples above are common measurements for results of these tests.Aug 29, 2015
Sodium urine test: MedlinePlus Medical Encyclopedia
@ryan31337, do you typically do a 24 hr collection or a random sample?
 

ryan31337

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Interesting, either way sounds like you need more salt!

Yes, my test was 24hr collection, important to get a good overall picture.

Before the test I mentioned I had similar problems with excessive thirst and urination, I was often peeing 5 to 6L a day. Exercise & high carb meals made this considerably worse. I'd go for a swim, eat a big portion of pasta for lunch and then drink 3L of water and still be thirsty.

This improved along with all the other symptoms of poorly controlled blood glucose when I switched to a ketogenic diet. No diabetes but seems most strongly linked to digestive problems associated to POTS for me. I'm only peeing 3-4L a day now and that's because I purposefully chug the water and electrolytes.
 

Ema

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Interesting, either way sounds like you need more salt!

Yes, my test was 24hr collection, important to get a good overall picture.

Before the test I mentioned I had similar problems with excessive thirst and urination, I was often peeing 5 to 6L a day. Exercise & high carb meals made this considerably worse. I'd go for a swim, eat a big portion of pasta for lunch and then drink 3L of water and still be thirsty.

This improved along with all the other symptoms of poorly controlled blood glucose when I switched to a ketogenic diet. No diabetes but seems most strongly linked to digestive problems associated to POTS for me. I'm only peeing 3-4L a day now and that's because I purposefully chug the water and electrolytes.
A ketogenic diet has been my best intervention too.
Huge improvements in health, but alas, not the peeing problem, haha.

I’ve been thinking about desmopressin again. I was on aldosterone/Florinef for years and it didn’t help that much.
 

kangaSue

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Before the test I mentioned I had similar problems with excessive thirst and urination, I was often peeing 5 to 6L a day. Exercise & high carb meals made this considerably worse. I'd go for a swim, eat a big portion of pasta for lunch and then drink 3L of water and still be thirsty.
Can be SIADH (Syndrome of inappropriate antidiuretic hormone secretion)

I’ve been thinking about desmopressin again. I was on aldosterone/Florinef for years and it didn’t help that much
There's debate about whether the issue is hypovolemia or dysfunction of the main circulatory blood volume regulators. This paper suggests the latter may be down-regulated and desmopressin may be beneficial.

https://www.ncbi.nlm.nih.gov/pubmed/27401397
CONCLUSIONS: Both the renin-aldosterone and ADH systems were down-regulated despite the existence of reduction in cardiac preload and output in patients with ME. Desmopressin improved symptoms in half of the patients
 

Rlman

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does polyuria have any negatives effects on health if one drinks more water to compensate for the fluid loss? is there a loss of nutrients due to increased urine output?
 

Rlman

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Hi @Rlman,

General advice is that you should add electrolytes when consuming extra fluids. The reasoning being that you will be peeing out more salts and risk lower blood pressure.

Ryan
salts you mean all electrolytes or just Na? on my blood tests na usually great, potassium at 3.8 sometimes (in range but i think ideal 4 at least?). Thanks for your help @ryan31337
 

ryan31337

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Yes, balance is often said to be important. I think there is also an issue of buffering being required to get the rather high quantities of salt into your body without irritating the stomach too.

Personally I just take cheap basic electrolyte powders made for athletes, but its not really giving the levels of salt my doctors wants so I might need to try something else.

Check out a product by SaltStick called Vitassium, it was released in conjunction with Dysautonomia International.

Ryan
 

Rlman

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If you want to look a bit more into potential causes another blood test that may be useful is Aldosterone.

Aldosterone is a hormone that conserves salt, mine was out of range low on testing. Because of that I was booked in for an ACTH Stim test + repeat aldosterone test under suspicion of isolated mineralocorticoid deficiency, but this time round everything worked normally... the fun world of POTS...
my aldosterone and renin were high normal when i tested it when didn't eat salt for week preceding. i think ppl with diabetes insipidus (which i probably have as pee a lot) have such results, body's way to keep volume higher than would be possibly