Question

Which statement correctly distinguishes renal failure from prerenal failure?

A. With prerenal failure, vasoactive substances such as dopamine (Intropin) increase BP
B. With prerenal failure, there is less response to such diuretics as furosemide (Lasix)
C. With prerenal failure, an IV isotonic saline infusion increases urine output
D. With prerenal failure, hemodialysis reduces the BUN level

Answer 1

The correct distinction between renal failure and prerenal failure is that, in prerenal failure, an IV isotonic saline infusion can increase urine output by improving blood flow to the kidneys, while actual kidney damage in renal failure does not respond the same way to fluid administration.

Step-by-step explanation:

The statement that correctly distinguishes renal failure from prerenal failure is C. With prerenal failure, an IV isotonic saline infusion increases urine output. Prerenal failure is caused by conditions that impair the blood flow to the kidneys before it reaches them, which does not usually involve direct kidney damage. Therefore, improving the blood flow, such as with an IV isotonic saline infusion, can improve urine output because it addresses the underlying issue of decreased blood flow.

Renal failure, conversely, involves damage to the kidneys themselves and is not typically responsive to fluid administration in the same way prerenal failure is. This damage can lead to the inability of the kidneys to filter blood effectively, which can cause a buildup of wastes in the blood and potentially develop into chronic kidney disease. Prerenal failure and renal failure have different therapeutic interventions and prognoses, making proper differentiation critical for treatment.