Early assessment of organ involvement in hypertension: renal assessment.

Hypertension in the malignant phase is all too commonly associated with impairment of renal function, which may be gross and dominate the clinical picture. In contrast, the vast majority of patients with essential hypertension show no evidence of impairment of renal function, despite the well recognized morbid anatomical changes of Renal haemodynamic changes can be detected in some two-thirds of hypertensive subjects with a variable decrease in renal blood flow and increase in filtration fraction. This pattern could be considered a potential mechanism for hyperfiltration damage to glomeruli, but there is no direct evidence. Estimates of renal blood flow and glomerular filtration rate are not sensitive indices of early renal damage of hypertensive origin. Much more sensitive but relatively unexplored is the measurement of micro-albuminuria in hypertensive patients. There is some evidence that the degree of micro-albuminuria may correlate inversely with the control of arterial pressure in essential hypertension. These observations and the suggestion that increased urinary N-acetyl-beta-D-glucosaminidase may be a sensitive index of renal tubular damage need further confirmation.