Renal artery stenosis
- Lesion
A narrowed renal artery makes the kidney release renin, raising blood pressure; the kidney behind it shrinks.
What it is
Renal artery stenosis causes a small but curable share of hypertension. Reduced pressure at the juxtaglomerular apparatus switches on the renin-angiotensin-aldosterone system, as in Goldblatt's experiments. Most cases are atherosclerotic plaques at the origin of the artery in older people; the rest are fibromuscular dysplasia, mostly in young women. Bilateral or solitary-kidney stenosis can also cause ischemic nephropathy, a slow loss of function.
Structure
- The affected kidney is smaller; glomeruli lie close together because tubules have atrophied.
- Its arterioles show little hyalinosis because they are shielded from systemic pressure, while the opposite kidney shows hypertensive damage.
- Fibromuscular dysplasia: ridges of thickened media alternating with thinned segments and small aneurysms.
Two causes of renal artery stenosis
| Cause | Who | Lesion | Site |
|---|---|---|---|
| Atherosclerotic stenosis | About two thirds of cases; older adults, more often men | Plaque narrowing the lumen | Origin and first part of the artery |
| Fibromuscular dysplasia | Young women | Fibrous and muscular thickening of the media, with small aneurysms | Middle and distal artery; carotids may also be involved |
Clinical notes
- Suspect it in severe or resistant hypertension, sudden onset before 30 or after 55, an abdominal bruit, or a rise in creatinine after starting ACE inhibitors.
- Atherosclerotic ischemic renal disease often coexists with coronary and peripheral artery disease.
Test yourself
Think of the answer, then tap the question to see it.
How does renal artery stenosis raise blood pressure?
Lower perfusion pressure at the juxtaglomerular apparatus stimulates renin release, activating angiotensin II and aldosterone.
What angiographic image is typical of fibromuscular dysplasia?
A string of beads: alternating narrowings and dilatations of the mid or distal renal artery.
Why does the stenotic kidney show little arteriolar hyalinosis?
Its arterioles are protected from the high systemic pressure by the upstream narrowing.
Elsewhere in DurgiPedia
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Renovascular hypertension: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.