What's the difference between syndrome of inappropriate antidiuretic hormone (or SIADH)
and Diabetes Insipidus?
I'm going to break it down really simple for you so you can finally understand it for nursing
school.
Hey there friend, Christina here with nursingschoolofsuccess.com and this video is all about the difference
between SIADH and diabetes insipidus.
Now I want to mention, I do have a free cheat sheet for you, it's called the med-surg study
checklist, so you can use it to help you study for your med-surg classes and all of the disorders
you need to learn, like SIADH and diabetes insipidus.
The link is down below in the description for you to snag it.
So SIADH and Diabetes Insipidus have to do with a little hormone called ADH.
And ADH stands for antidiuretic hormone.
So antidiuretic hormone, or ADH, is exactly what it sounds like, it's an ANTI diuretic.
And what do diuretics do?
They make you urinate, a lot!
So ADH, is ANTI-diuretic hormone, meaning that you won't urinate a lot.
So it's the reverse.
When ADH is released into the body, it goes and tells the kidneys to hold onto water,
instead of urinating it out.
So normally, when the body has a low fluid volume (meaning, there isn't enough water
in the body), ADH is released from the posterior pituitary gland and it tells the kidneys to
hold onto more water, rather than sending that water out into the urine.
This will increase the fluid volume in the body because the kidneys won't be sending
as much water out into the urine.
Now, SIADH stands for syndrome of inappropriate antidiuretic hormone.
The name actually tells you what's happening, which is pretty nice.
There is inappropriate antidiuretic hormone being released, meaning the even when the
body doesn't need it, ADH is still being released.
This is inappropriate ADH release, thus the name.
During SIADH, the posterior pituitary gland releases ADH even if the fluid volume isn't
low.
So even if the fluid volume in the body is totally fine, there is still too much ADH
being released.
And this causes increased fluid volume in the body and possibly fluid overload.
So that's what's happening during SIADH: ADH is being released inappropriately, even when
it's not supposed to.
And ADH goes and tells the kidneys to hold onto more and more water, which then causes
the fluid volume to keep going up, possibly leading to fluid overload.
Now, the reverse of this is diabetes insipidus, or DI for short.
During diabetes insipidus, the posterior pituitary gland does not release enough ADH, OR the
kidneys don't respond to it, either one of those 2 causes.
So during diabetes insipidus, there isn't enough ADH to start with, or the kidneys just
don't respond to it.
Either way, there's nothing to tell the kidneys to HOLD ONTO water.
So what are the kidneys going to do if there's nothing telling them to hold onto water?
They are going to get rid of it!
They're going to send all of that water out into the urine, and that's exactly what's
happening during diabetes insipidus.
The kidneys are getting rid of a lot of water because they don't have ADH telling them to
hold onto it.
This causes the fluid volume to get lower and lower, because the kidneys keep getting
rid of more and more water.
And
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I'll catch you in the next video.