Cardiovascular system: renal artery stenosis: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Cardiovascular system: renal artery stenosis

Sample item

A 60-year-old with resistant hypertension and an abdominal bruit develops acute kidney injury within days of starting an ACE inhibitor. Imaging shows bilateral renal artery stenosis. What explains the fall in GFR?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Loss of angiotensin II mediated efferent arteriolar constriction

With stenosis, GFR is kept up by angiotensin II constricting the efferent arteriole. ACE inhibition removes this tone, lowering glomerular capillary pressure so that GFR falls. Creatinine rises soon after starting the drug.

Option by option

  • A. Loss of angiotensin II mediated efferent arteriolar constriction (correct)

    Correct. Without efferent constriction, filtration pressure falls in stenotic kidneys.

  • B. Increased glomerular hydrostatic pressure

    Glomerular hydrostatic pressure falls rather than rises.

  • C. Rise in plasma oncotic pressure

    Plasma oncotic pressure is not affected by ACE inhibition.

  • D. Dilatation of the afferent arterioles

    ACE inhibitors dilate the efferent arteriole, not the afferent.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is A, Loss of angiotensin II mediated efferent arteriolar constriction. With stenosis, GFR is kept up by angiotensin II constricting the efferent arteriole.

Why is "Increased glomerular hydrostatic pressure" not the answer?

Glomerular hydrostatic pressure falls rather than rises.

Why is "Rise in plasma oncotic pressure" not the answer?

Plasma oncotic pressure is not affected by ACE inhibition.

Why is "Dilatation of the afferent arterioles" not the answer?

ACE inhibitors dilate the efferent arteriole, not the afferent.

What concept does this question test?

It tests Cardiovascular system: renal artery stenosis in Physiology. ACE inhibition removes this tone, lowering glomerular capillary pressure so that GFR falls. Creatinine rises soon after starting the drug.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Cardiovascular system: renal artery stenosis?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.