Renal artery stenosis

Introduction Renal hypertension caused by renal artery stenosis, accounting for 5%-10% of patients with hypertension. The causes of renal artery stenosis are common atherosclerosis, multiple arteritis and renal artery muscle fibrosis. The former is more common in the elderly, the latter two are common in young people, especially women. The severity of renal artery stenosis varies from obvious renal artery stenosis to small renal artery lesions that are not clinically detectable. Severe stenosis can cause renal perfusion damage, decreased glomerular filtration rate (GFR), resulting in sodium retention, increased extracellular fluid volume, hypertension and renal failure.

Cause

Common causes of renal artery stenosis are atherosclerosis, fibromuscular dysplasia, and arteritis. Aortic inflammation is a chronic non-specific inflammation of the main artery and major branches, involving the renal artery causing stenosis and renal ischemia, which occurs in women under 30 years of age. Renal artery muscle fiber structure is poor, the lesion is located in the distal 2 / 3 of the renal artery and its branches, more common in young and middle-aged women.

an examination

1. Captopril-renin challenge test: Under normal circumstances, after taking the conversion enzyme inhibitor captopril, the body's high renin response can be enhanced by inhibiting the negative feedback of angiotensin II. This reaction is particularly prominent in patients with renal artery stenosis, and the increase in plasma renin after oral captopril is significantly greater than that in essential hypertension. The sensitivity and specificity of this test can reach 93% to 100% and 80% to 95%, respectively.

2. Captopril-radio-nuclear kidney map: Stimulation of renin-angiotensin system activity in renal artery stenosis, and the contraction of angiotensin II to the small arterioles helps maintain glomerular internal pressure and Glomerular filtration rate. Use of a conversion enzyme inhibitor (such as captopril) to inhibit the production of angiotensin II, can reduce glomerular internal pressure and glomerular filtration rate, before and after taking captopril, using radionuclide The technique is more ideal for detecting ischemic conditions in unilateral kidneys with a sensitivity and specificity of more than 90%.

Differential diagnosis

diagnosis

Differential diagnosis of renal artery stenosis includes:

1 renal artery congenital dysplasia: generally the entire segment of the renal artery with renal dysplasia.

2 atrophic pyelonephritis: the renal artery trunk has no localized stenosis, the intrarenal artery is generally thin and often close to each other or curled, renal parenchymal atrophy with irregular shape, no renal artery stenosis after expansion and collateral circulation.

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