Renal Disease

Renal disease is the most common cause of secondary hypertension. Parenchymal renal disease, both acute and chronic, results primarily in volume overload due to impaired salt and water excretion. High renin levels may also contribute. Initial screening tests include a urinalysis, urine microalbumin, BUN and creatinine. Vascular renal disease with renal artery stenosis reduces renal blood flow. This sets off the renin-angiotensin-aldosterone mechanism, that results in peripheral vasoconstriction.

Renal artery stenosis should be suspected when hypertension: is severe; is of sudden onset; is resistant to treatment, or is associated with an abdominal or flank bruit, especially if the bruit is continuous, or, if there is a marked increase in BUN / creatinine with ACE-I therapy. The underlying cause in young females may be fibromuscular dysplasia of the renal arteries. In older patients and smokers, atherosclerosis is more likely.

Renal arteriography is the gold standard for the diagnosis of renal artery stenosis. Non-invasive tests such as magnetic resonance, CT angiography or Doppler ultrasound are also used.

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