[Treatment of hypertension in renal parenchymal diseases]

Hypertension is a common finding in patients with renal parenchymatous diseases. Development of hypertension causes increased proteinuria, decline in glomerular filtration rate and reduced life span in experimental models of glomerulonephritis. Hypertension has been shown to reduce glomerular filtration rate in man. It is therefore important to treat hypertension. The blood pressure should be reduced to about 140/80 mm Hg. Reduction of glomerular capillary pressure, inhibition of glomerular permeability, renal hypertrophy and inhibition of mesangial metabolism are the main mechanisms of renal protection during antihypertensive therapy. Autoregulation of the renal blood flow probably has an impact on these mechanisms. Impaired autoregulation is found in kidneys with low glomerular filtration rate and during treatment with calcium channel blockers. Alpha receptor blockers, angiotensin converting enzyme inhibitors (ACE-) and angiotensin II receptor blockers do not interfere with autoregulation. All types of antihypertensive drugs provide similar renal protection when the glomerular filtration rate is reduced. When calcium channel blockers are used in kidneys with normal or slightly reduced function, either blood pressure should be kept strictly at normal levels or these type of drugs should be combined with ACE inhibitors or angiotensin II receptor blockers.