diabetes 1 question

jennifers · Feb 23, 2009

I wanted to also point out that they are saying that Diabetes I has nothing to do with the pituitary it is autoimmune. So Dont I have to rule out anything brain related such as a thirst center? The polydipsia is throwing me. Thanks for any help.

blondy2061h, MSN, RN · Feb 23, 2009

The kidneys excrete glucose once the blood glucose raises above 180 in an attempt to lower glucose. The glucose drags urine out with it- polyuria. The result is dehydration- polydipsia.

jennifers · Feb 23, 2009

Thank you. I guess thats why when the kidneys are overworked it can lead to nephropathy.

So its more like the polyuria causes the polydipsia instead of the other way around. I was trying to figure out the reason for the excess thirst instead of the reason for the excess urination. Makes sense now. Thanks!

Saifudin · Feb 23, 2009

That's correct diabetes type I and II are not related to the pituitary. Type I, meaning a total lack of insulin is likely autoimmune. There is evidence that beta cell damage may be secondary to a past viral infection.

Diabetes Insipidus can be mediated by a lack of Antidiuretic hormone (ADH) that is produced by the pituitary gland. ADH or vasopressin causes the kidneys to conserve water.

In DM, particularly Type I the related elevated blood glucose has a diuretic effect in the kidney causing fluid loss that can be dramatic. The resulting 'thirst' is related to dehydration and is a protective mechanism to cause the person to take fluids. Of course, this reaches a state that the fluid loss is too great, the glucose too high and the patient severely dehydrated leading metabolic acidosis and diabetic ketoacidosis (DKA).

blondy2061h, MSN, RN · Feb 23, 2009

Thank you. I guess thats why when the kidneys are overworked it can lead to nephropathy.
So its more like the polyuria causes the polydipsia instead of the other way around. I was trying to figure out the reason for the excess thirst instead of the reason for the excess urination. Makes sense now. Thanks!

That's part of it, but glucose molecules are large. When excessive glucose is passing through small blood vessels, it can damage them just because it's more mass than these small blood vessels were meant to accommodate. That's a big reason for nephropathy and retinophaty. It's also a huge reason why eye exams are important. It's hard to look at the kidneys, but easy to look at the retina. If there's damage to the retina, it can be assumed that there's damage to the kidney.

jennifers · Feb 23, 2009

thanks!

Daytonite, BSN, RN · Feb 24, 2009

what causes the polydipsia??

the patient is dehydrated. because the glucose cannot get into the cells to be metabolized it builds up in the circulating blood. the kidneys attempt to filter it out. when the glucose in the blood reaches a level of more than 180mg/dl the kidneys start to filter glucose out of the blood and excrete it into the urine. it requires water to do this. as glucose levels rise, the kidneys attempt to excrete more and more glucose using more and more water until the body becomes dehydrated if the water is not replaced. homeostatic factors cause the body to become thirsty and crave water to replace what is being lost through the urine. so, the patient will become polydipsic, or start drinking a lot of water and fluids.