h2O and Na

[cdb6c]

i know that where water goes, sodium goes. just got confused...so if there is an edema (water retention), there's hypernatremia???? In SIADH, there is a decreased urine output (of course) but why is sodium decreased too???

help!

[hopingtobeanRNsoon]

i got confused by that too but just remember the facts for DI and SIADH...its just different for that type of diseases...dont get too overwhelmed by it...

[wannabenars]

i know that where water goes, sodium goes. just got confused...so if there is an edema (water retention), there's hypernatremia???? In SIADH, there is a decreased urine output (of course) but why is sodium decreased too???

help!

in SIADH, its not necessarily that Na is decreased, but rather, you have more water in proportion to your Na because you're not excreting enough water. It's called dilutional hypoNa because the Na gets diluted with more H2o. That's how i understand it. please correct me if im wrong.

This is how I remember it:

-SIADH--dec water excretion, too much water, lil sodium=dilutional hypoNa

-Diab Insip--too much water excretion, sodium gets concentrated in lil water=hyperNa

hope that helps.

[cdb6c]

thanks! now I have an idea about that topic!

[ElliShay]

i know that where water goes, sodium goes. just got confused...so if there is an edema (water retention), there's hypernatremia???? In SIADH, there is a decreased urine output (of course) but why is sodium decreased too???

help!

Actually-- water follows sodium (as opposed to the other way around) since sodium is a major determinant of osmolality.

Remember--

Aldosterone controls sodium (increased aldosterone release = increased sodium retention)

ADH controls water (increased ADH = increased water retention)

SIADH = increased water retention and dilution of sodium (because aldosterone is not a player in this situation)

[spongebob6286, BSN, RN]

sodium attracts water.

in SIADH sodium is decreades because it gets diluted by the increased water since it isnt excreted.