Hypertension in the neonate.

Blood pressure (BP) is low at birth. It increases with age, by about 1 mm Hg per day within the period of 3 to 8 days. It rises by about 1 mm Hg per week between ages 5 to 6 weeks. At a latter age, systolic BP is close to 95 +/- 10 mm Hg. Hypertension is a rare condition in the neonate, where it carries a high risk of cardiorespiratory failure and cerebral distress. Causes of neonatal hypertension are either secondary to congenital malformations or to acquired disease states: Congenital malformations: renal artery stenosis, renal artery hypoplasia, abdominal aortic atresia, coarctation of the aorta, kidney cystic disease, reflux nephropathies. Acquired diseases: thrombo-embolic renal artery complications secondary to umbilical artery catheterization or to thrombosis of ductus arteriosus, closure of abdominal wall defects, adrenal hematoma with renal artery compression, seizures in preterm infants, central nervous system disorders, drug-induced hypertension, infants of drug-dependent mothers. The morbidity and the mortality of neonatal hypertension are elevated. Death may be caused by severe uncontrollable hypertension or by concomitant problems. Morbidity may be related to drug-resistant hypertension, or to the side-effects of hypotensive drugs. Surgery in these severely ill infants also carries a significant risk.