Arterial hypertension in infants with hydronephrosis. Report of six cases.

Six infants with hydronephrosis developed hypertension during the first year of life. Five of them, all with proved or suspected acute urinary tract infection, had transient hypertensive episodes lasting for 7 to 17 days. One of the five infants, who had ureteropelvic junction obstruction and unilateral hydronephrosis, remained normotensive after nephrectomy. The sixth patient, with bilateral hydronephrosis and elevated peripheral vein renin activity, has had persistent hypertension. We discuss possible mechanisms underlying hypertension in these infants and suggest that young patients with hydronephrosis may be unusually predisposed to acute hypertensive episodes.