Does lithium cause HYPO or HYPERnatremia?

[johndoe3344]

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The book I'm reading and the interwebs seem to say that lithium causes hyponatremia. But lithium causes nephrogenic diabetes insipidus = hypernatremia. Can someone explain?

 

[Brain Bucket]

The book I'm reading and the interwebs seem to say that lithium causes hyponatremia. But lithium causes nephrogenic diabetes insipidus = hypernatremia. Can someone explain?

Put the page up? I agree with Li - ADH > Neph D.I. > Pure water loss > euvolemic hypernatremia.

 

[johndoe3344]

On second look, I think I might have misread what the page says. Thanks.

 

[SpecterGT260]

Put the page up? I agree with Li - ADH > Neph D.I. > Pure water loss > euvolemic hypernatremia.

I never got why this was a euvolemic hypernatremia. The JGA freaks out and you get an aldo spike which is why you get a hypokalemia and most sodium is retained. I would expect someone to be hypovolemic and hypernatremic on labs, but they may actually have low total body sodium.

EDIT: I went back and checked some notes. Are you sure you aren't confusing Neph. DI with SIADH? In our notes we don't really differentiate or discuss volume status for hypernatremia. But for hyponatremias we do. SIADH is a euvolemic hypOnatremia because the increased ADH -> water retention -> shut down of renin/angiotensin/aldosterone -> sodium loss, which balances the water in/out and you get euvolemic hyponatremia.

 

[SpecterGT260]

https://www.muschealth.com/nutrition/documents/Hyponatremia.pdf

this says they are either euvolemic or hypervolemic. Is that due to the Osms derangement causing polydypsia? Outside of that I can't come up with any reason why peeing too much would cause hypERvolemia

 

[Brain Bucket]

I never got why this was a euvolemic hypernatremia. The JGA freaks out and you get an aldo spike which is why you get a hypokalemia and most sodium is retained. I would expect someone to be hypovolemic and hypernatremic on labs, but they may actually have low total body sodium.

EDIT: I went back and checked some notes. Are you sure you aren't confusing Neph. DI with SIADH? In our notes we don't really differentiate or discuss volume status for hypernatremia. But for hyponatremias we do. SIADH is a euvolemic hypOnatremia because the increased ADH -> water retention -> shut down of renin/angiotensin/aldosterone -> sodium loss, which balances the water in/out and you get euvolemic hyponatremia.

I'm sure 😉

http://www.merckmanuals.com/profess...trolyte_disorders/hypernatremia.html#v1149631

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[Brain Bucket]

https://www.muschealth.com/nutrition/documents/Hyponatremia.pdf

this says they are either euvolemic or hypervolemic. Is that due to the Osms derangement causing polydypsia? Outside of that I can't come up with any reason why peeing too much would cause hypERvolemia

I don't have my books with me and we haven't gotten into NDI yet in class, but my best guess -

It is hypernatremia, so there is a decrease in total body water, but the euvolemic here implies loss of Na = loss of H2O.

This drop in TBW will lead to a decreased GFR and increased water reabsorption (Epi and Angio II) at the PCT, so even though the ADH action is messed up, there isn't all that much (relatively) water reaching the CT anyway.



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