Kinda crazy question about SIADH

[KeikoTanaka]

So, I'm studying for my Renal Mod right now... and I came across this Anki card that is SIADH Treatment:

Fluid Restriction <800 mL/24 hours (Fluid Electrolyte concentration must be greater concentration than electrolytes in urine)

So, here's my crazy question...

If you had a bunch of people stranded out in sea, would a person with SIADH, drinking 800mL of sea water daily, survive longer than the "healthy" individuals?

Also, in a less extreme example, would Gatorade actually be more beneficial of a liquid to drink 800 mL of if you had SIADH over straight up tap water?

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[Throwawaycall]

Sounds like a good case presentation. I’ll shoot up some vasopressin and drink the Gatorade you can do the fish poop soup.

 

[Ho0v-man]

 

[Drrrrrr. Celty]

1) If you have SIADH you likely have a primary condition causing SIADH. Most common one being pneumonia.

2) The treatment for SIADH is treat the primary condition. Fluid restriction keeps you from needing to send the patient to the ICU.

 

[MADD!!!]

So, I'm studying for my Renal Mod right now... and I came across this Anki card that is SIADH Treatment:

Fluid Restriction <800 mL/24 hours (Fluid Electrolyte concentration must be greater concentration than electrolytes in urine)

So, here's my crazy question...

If you had a bunch of people stranded out in sea, would a person with SIADH, drinking 800mL of sea water daily, survive longer than the "healthy" individuals?

Also, in a less extreme example, would Gatorade actually be more beneficial of a liquid to drink 800 mL of if you had SIADH over straight up tap water?

Giving my shot at this (not sure if it’s right or not). If you’re drinking sea water, you will be excreting a lot of salt —> excretion of lots of fluid —> dehydration and hypovolemia —> maximal ADH secretion. So In essence in these conditions, the normal response would be to maximally secrete ADH to attempt to retain as much water as possible as well.

2) Gatorade would make it worse because you’re adding even more electrolytes in a solution where you have too much electrolytes to begin with.

Let me know your thoughts, I wonder if this is how it works or not.

 

[MADD!!!]

So, I'm studying for my Renal Mod right now... and I came across this Anki card that is SIADH Treatment:

Fluid Restriction <800 mL/24 hours (Fluid Electrolyte concentration must be greater concentration than electrolytes in urine)

So, here's my crazy question...

If you had a bunch of people stranded out in sea, would a person with SIADH, drinking 800mL of sea water daily, survive longer than the "healthy" individuals?

Also, in a less extreme example, would Gatorade actually be more beneficial of a liquid to drink 800 mL of if you had SIADH over straight up tap water?

I think if you also flipped it where no one was drinking any water at all, the pt. with SIADH would have a better survival rate b/c they've retained their water for a longer period of time?

 

[deleted645092]

Giving my shot at this (not sure if it’s right or not). If you’re drinking sea water, you will be excreting a lot of salt —> excretion of lots of fluid —> dehydration and hypovolemia —> maximal ADH secretion. So In essence in these conditions, the normal response would be to maximally secrete ADH to attempt to retain as much water as possible as well.

2) Gatorade would make it worse because you’re adding even more electrolytes in a solution where you have too much electrolytes to begin with.

Let me know your thoughts, I wonder if this is how it works or not.

You’re correct about the salt excretion, however technically you’d actually be treating the hyponatremia resulting from the SIADH through the extra water loss so at least you won’t have seizures while dying of dehydration? I might also add that I believe that seawater also has an osmotic-laxative effect in the intestines due to loss of the osmotic gradient that normally promote electrolyte absorption, so you’d end up losing more water through there as well. Overall you wouldn’t last longer but it would have a therapeutic effect for the first day or so if you had symptomatic hyponatremia.

As for the Gatorade you actually wouldn’t be causing any issues with electrolytes because the main electrolyte balance issue you’re concerned about in SIADH is hyponatremia, not hypernatremia, which is why part of treatment for resistant or symptomatic SIADH is oral salt tablets and/ or hypertonic saline. A quick Google search told me that Gatorade has 63mEq of sodium so it theoretically can overcome the urine sodium loss, assuming ~40mEq loss per day which is the average in SIADH according to UptoDate. However I also found a study that stated isotonic sports drinks such as Gatorade don’t actually prevent hyponatremia by any significant degree compared to plain water, although they do replace the other electrolytes in adequate amounts such as potassium. In addition you’d have them taking in 32g of sugar per liter so you don’t want to do that either. So theoretically you could, but practically no.