Hypertension in the first month of life.

We reviewed our 10-year experience with neonatal hypertension. Fifty-three cases were identified, which represented 0.7% of all neonatal tertiary care admissions. Causes were identified in 23 (43%) neonates. These included acute tubular necrosis (n = 7), renal vascular abnormalities (n = 8), renal structural abnormalities (n = 4), interstitial nephritis (n = 2), and coarctation of the aorta (n = 2). No cause was identified in 30 (57%) infants. If the two neonates with coarctation are excluded, infants who had normal urinalyses, blood urea nitrogen (BUN), serum creatinine and plasma renin activity (PRA), had non-malignant hypertension that tended to be short-lived and always resolved spontaneously. In contrast, a cause of hypertension was found in 68% of those having an abnormal urinalysis, BUN, serum creatinine or PRA. There were two hypertensive deaths in this group. While the hypertension was usually more prolonged, it still generally resolved spontaneously by 1 year of age or following corrective surgery. Our experience indicates that diagnostic studies can be postponed if the urinalysis, BUN, serum creatinine and PRA are normal and if coarctation of the aorta has been excluded. If these preliminary studies are abnormal, however, a renal cause is likely and further studies are indicated.