A case of hypertension due to unilateral hydronephrosis in a child

A case of hypertension secondary to unilateral hydronephrosis due to congenital obstruction of ureteropelvic junction in a 6-year-old boy is reported. Preoperatively, the plasma renin activity (PRA) in the peripheral vein and in the affected kidney was elevated. Blood pressure decreased significantly following administration of converting enzyme inhibitor. After nephrectomy, peripheral vein PRA and blood pressure returned to normal, despite withdrawal of antihypertensive medication and sodium restriction. Histological examination of the resected kidney revealed prominent hyperplasia of juxtaglomerular cells. These results strongly suggest that, in this case, hypertension was renin-dependent.