Transient hypertension with urinary tract infection in congenital hydronephrosis.

Introduction: Hypertension is occasionally associated with congenital hydronephrosis.

Case report: The authors report a four-month-old boy with severe left congenital hydronephrosis and transient hypertension triggered by his first urinary tract infection (UTI). Despite the satisfactory UTI clinical course, he suddenly developed severe hypertension (130/80 mmHg) on the ninth day of UTI. His aldosterone level was within the reference range and his plasma renin activity was slightly elevated. Although his hypertension was refractory to calcium channel blockers, an angiotensin-converting enzyme inhibitor was effective for hypertension. On day 24, he was able to discontinue the antihypertensive without organ damage.

Conclusions: Although the precise cause of hypertension was unclear in our case, we considered it to be temporary renin-associated hypertension due to decreasing renal blood flow due to UTI in a patient with severe congenital hydronephrosis. In pediatric UTI, particularly in patients with unilateral hydronephrosis, blood pressure monitoring is very important.