OLD Q BANK:q35 - hallucination

[ArchivalUser]

35>A 40-year-old woman presents to the emergency department because of
hematuria. Laboratory analyses show significant proteinuria, bacteria
and white cells in the urine, and a blood urea nitrogen (BUN) of
40 mg/dL with a creatinine of 4.0 mg/dL. Ultrasonography reveals
enlarged kidneys, and she is given a provisional diagnosis of
polycystic renal disease. Which of the following is likely to
be decreased in this patient?
A. Creatinine clearance
B. Extracellular sodium concentration
C. Glucose clearance
D. Plasma creatinine levels
E. Plasma inulin levels

[ArchivalUser]

B. Extracellular sodium concentration due to renal insufficiency?

[ArchivalUser]

My reasoning is, due to renal insufficiency, there will be hypervolemic state, so hyponatremia-decrease Na+ concentration in ECF?

[ArchivalUser]

the BUN/Cr ratio is 10:1 ;within normal limits.so,i dont think she is in renal failure.but,b/c cr. level has increased i think cr clearance has decreased.(A)

[ArchivalUser]

Normal BUN: 7-18, normal Cr: 0.6-1.2

Here BUN: 40, Cr: 18, why do you use the ratio to assess renal function?

[ArchivalUser]

But I agree with answer A

[ArchivalUser]

there is definate renal insufficiecy in this case. The issue though is that it might not be at the glomerular level as per the ratio. This ratio shows that they are both equally affected which might sugest that the filtration process is normal. I think this is a tubular problem which will mean that Na reabsorption is affected hence a reduced extra cellular concetration B.

[ArchivalUser]

its A.regarding the choice B(which some of ourfreinds had opted for)PCK causes compression of the renal parenchyma nad blood vessels decreasing the blood flow and stimulating RAS leading to increased aldosterone and increased Na and water retention.correct me if i'm wrong with my explanation

[ArchivalUser]

Naren you are right in that aspect,but apparently there is nothing in the history to sugest that for now. We have hematuria, wbc, bacteria which leads me to think that it is a pylelonephritis (tubular lesion).We have protenuria a reason lean towards a glomerulonephritis and that should have been the cause of the reduced creatinine clearence secondary to reduced GFR.Off cause the obstruction componet of the cysts can cause a whole mixed bag of pathology , thats why the U/C ratio is very important in this aspect. Iam still playing the B drums. Any more ideas out there please?

[ArchivalUser]

hallucination, answer please.