Differential Uric Acid Excretion in Essential and Renal Hypertension

In 59 hypertensive patients, differences between the two kidneys in the handling of uric acid were found in renal arterial stenosis and unilateral renal disease but were not found in essential hypertension and bilateral renal parenchymal disease. The differences were greatest in 11 patients with unilateral renal arterial stenosis and were derived from reduced uric acid excretion per unit of glomerular filtration rate by the ischemic kidney. Six patients with unilateral stenosis underwent surgery with subsequent cure of hypertension. Another patient, who did not have impaired ipsilateral uric acid excretion, failed to respond to nephrectomy. Successful revascularization of the ischemic kidney in two patients augmented uric acid excretion with disappearance of the differences between the kidneys. Hyperuricemia was often found in all groups of hypertensive patients. Although the mechanisms underlying the differences in renal handling of uric acid are undefined, separate determinations of the uric acid excretion by the two kidneys may possibly prove useful in the evaluation of patients with hypertension.