Atlas of Neonatal Pathology: Persistent pulmonary hypertension of the newborn (persistent fetal circulation)

+ Introduction

+ Support

+ Neonatal pathology

Persistent pulmonary hypertension of the newborn (persistent fetal circulation)

Introduction

Failure to reduce pulmonary vascular resistance in the postnatal period

Etiology, pathogenesis

primary (idiopathic) — affects term infants an has no obvious pulmonary or cardiovascular causes
secondary — with known etiology for example lung hypoplasia, masive meconium aspiration, pneumonia, congenital heart diseases or bronchopulmonary dysplasia

Clinical signs

Idiopathic PPHN:

central cyanosis
respiratory distress
right to left shunt across the foramen ovale and the ductus arteriosus
decreased pulmonary blood flow

Histology

Preacinar and intra-acinar pulmonary arteries and arterioles show medial hyperplasia with extension of smooth muscle into small peripheral vessels. It is likely that the arterial changes begin in utero from increased sensitivity to hypoxia or stress or primary failure of mechanism governing arterial muscularization.