Kidney stones and Acute renal failure

[medInUSA]

A Qbank question I recently did said that kidney stones are unlikely to cause acute renal failure but are very likely to cause pyelonephritis.

If the stone obstructs the outflow the urine would back out and decrease the GFR, and acute renal failure is defined as the sudden dramatic decrease in GFR why cannt kidney stones cause ARF??

thank you in advance

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[indo]

kidney stones in the situation you described cause post-renal failure...i believe. Obstructions= post-renal, blood flood restrictions = pre-renal, and kidney damage= renal

 

[vtucci]

Agree with indo.

It is a language nuance. Post-renal after the glomerulus and kidney, as with urinary obstruction. Pre-renal, before the glomerulus- as with an obstruction- renal artery stenosis. Renal deals with the glomerulus and kidney apparatus itself. Also, pre-renal or post-renal can lead to renal failure but in this case, I believe it would be more chronic than acute. There are also different BUN/Creatinine ratios associated with pre-renal v. renal.

 

[medInUSA]

Thank you very much,

I guess Kaplan got this one wrong, Qbank

 

[fakin' the funk]

I guess Kaplan got this one wrong, Qbank

Nope, YOU'RE wrong. Kidney stones ARE unlikely to cause ARF, b/c the occlusion would have to be nearly complete bilaterally; this is unlikely.

Pyelonephritis is far more likely b/c many sizes of kidney stone can cause urinary stasis and predispose to infection.

Stop posting QBank questions that you don't get. That's what the EXPLANATION is for.

 

[exmike]

A Qbank question I recently did said that kidney stones are unlikely to cause acute renal failure but are very likely to cause pyelonephritis.

If the stone obstructs the outflow the urine would back out and decrease the GFR, and acute renal failure is defined as the sudden dramatic decrease in GFR why cannt kidney stones cause ARF??

thank you in advance

I suppose it could cause ARF.. if you already sold one of your kidneys to pay for med school.

 

[Whisker Barrel Cortex]

One healthy kidney can function enough to maintain GFR and prevent ARF. Thus, as mentioned above, unless the patient only has one kidney or just happens to have bilateral simultaneous tandem coordinated parallel stones causing obstruction, its not going to cause ARF.