Question about Renal Failure

[IcanHealYou]

Why is it that in ARF the first thing that happens is an Oliguric phase and then a Diuretic phase but on the other hand in CRF the first stage indicates polyuria and then oliguira?

[GilaRRT]

I am not sure you have a totally accurate clinical picture of renal failure, especially acute renal failure. In the setting of acute renal failure, the body is almost always not able to adapt to the sudden loss of renal function, therefore it is quite easy to appreciate the clinical and physiological differences between acute and chronic renal failure. In addition, chronic failure is almost always accompanied by a phase of renal insufficiency that can last many years without progression to "renal failure."

This concept of oliguria and diuresis is not totally accurate, because you can have decent output but not be filtering out toxins or regulating electrolytes effectively.

The best way to view acute renal failure is to ask what is the general cause.

You have three general causes to consider:

1) Pre-renal

2) Parenchymal

3) Post-renal

Each broad class has its own defining characteristics and clinical features.

Chronic renal failure can be seen as its own animal; however, acute renal failure can certainly progress to chronic renal failure.

Also remember that renal failure is not a condition by its self. Renal failure can be seen as the clinical course or outcome of any number of diseases or injuries. Therefore, it is crucial to focus on the underlying cause and not develop renal failure tunnel vision.

[IcanHealYou]

Hey Gila,

Thanks for answering my question again. I'm just going through what I've been taught in nursing school. In ARF ther are three phases. The Oliguric, Diuretic and recovery phase.

[GilaRRT]

I do think people talk about an early oliguric phase when uremia and electrolyte imbalance occurs, a diuresis phase with return of renal function, and a recovery phase; however painting such a broad picture of ARF is not totally accurate. It is not uncommon to have an initial diuresis indicating recovery, only to have the patient develop CRF. Additionally, in post-renal failure such as an obstruction, it is not uncommon to have a reflex action occur that can in fact preserve GFR until the pressure gradient equalizes and total movement ceases.

So, I think it is more important to study the categories and causes of ARF, because failure to identify and correct the underlying problem will result in CRF and/or death.

Unfortunately, you will most likely have to answer with whatever you're nursing instructors state as fact. "Cooperate to graduate" as the old saying goes.

[Tait, MSN, RN]

Unfortunately, you will most likely have to answer with whatever you're nursing instructors state as fact. "Cooperate to graduate" as the old saying goes.

This is too true...

Great responses Gila. Thank you.

Tait

[IcanHealYou]

Yea, this is for all for NCLEX studying =/