Anemia of Prematurity - Portal Neonatal

Neonatal Hypertension
Last Updated: June 7, 2004
Synonyms and related keywords: high blood pressure, high BP, premature infants
AUTHOR INFORMATION Section 1 of 10
Author: Joseph Flynn, MD, Director of Pediatric Hypertension Program, Division of Pediatric Nephro,
Children's Hospital at Montefiore; Associate Professor, Department of Pediatrics, Albert Einstein
College of Medicine
Joseph Flynn, MD, is a member of the following medical societies: American Academy of Pediatrics,
American Heart Association, American Society of Hypertension, American Society of Nephrology,
American Society of Pediatric Nephrology, National Kidney Foundation, and Phi Beta Kappa
Editor(s): Steven M Donn, MD, Professor of Pediatrics, Director, Neonatal-Perinatal Medicine,
Department of Pediatrics, University of Michigan Health System; Robert Konop, PharmD, Director,
Clinical Account Management, Ancillary Care Management; Arun Pramanik, MD, Professor,
Department of Pediatrics, Division of Neonatology, Louisiana State University Health Science Center;
Carol L Wagner, MD, Associate Professor, Department of Pediatrics, Division of Neonatology,
Medical University of South Carolina; and Neil N Finer, MD, Director, Division of Neonatology,
Professor, Department of Pediatrics, University of California at San Diego
INTRODUCTION Section 2 of 10
Background: Recent advances in the ability to identify, evaluate, and care for hypertensive infants,
coupled with advances in the practice of neonatology in general, have led to an increased awareness
of hypertension in modern neonatal intensive care units (NICUs) since its first description in the 1970s.
This article discusses an overview of the differential diagnosis of hypertension in the neonate, the
optimal diagnostic evaluation, and both immediate and long-term antihypertensive therapy.
Pathophysiology: Hypertension in newborn infants primarily is of renal origin, although cardiac,
endocrine, and pulmonary causes have been described as well. Therefore, the pathophysiology
depends on the organ system involved. For example, hypertension related to renal emboli primarily is
a high renin form of hypertension, whereas the hypertension associated with bronchopulmonary
dysplasia (BPD) is likely related to hypoxia. Such differences in pathophysiology are very important
because they can guide the clinician with respect to evaluation and treatment.
Frequency: In the US: Although precise figures are difficult to obtain, available data suggest that the
incidence of hypertension in newborns is low, with published figures ranging from 0.2-3%.
Hypertension is so unusual in otherwise healthy term infants that routine blood pressure (BP)
determination is not advocated for these patients. In 1992, Singh and colleagues found that in a group
of over 3000 infants admitted to a Chicago area NICU, the overall incidence of hypertension was
found to be 0.81%. Hypertension was considerably more common in infants with BPD, patent ductus
arteriosus, or intraventricular hemorrhage or in those who had indwelling umbilical arterial catheters.
Approximately 9% of the infants who had indwelling umbilical arterial catheters developed
hypertension.
Hypertension may also be detected following discharge from the NICU. In 1987, Friedman and
Hustead diagnosed hypertension (defined as a systolic BP >113 mm Hg on 3 consecutive visits over 6
wk) in 2.6% of infants discharged from a teaching hospital NICU. The diagnosis of hypertension was
made in these infants at a mean corrected age of approximately 2 months. Infants in this study who
developed hypertension tended to have lower initial Apgar scores and slightly longer NICU stays than
infants who remained normotensive, indicating that sicker babies have a somewhat greater likelihood
of developing hypertension. Although the number of babies affected is likely to be relatively small,
include screening for hypertension in the follow-up of NICU graduates, especially those with more
complicated NICU courses.