Lung Disease in Premature Neonates: Radiologic-Pathologic Correlation

Abstract

Pulmonary disease is the most important cause of morbidity in preterm neonates, whose lungs are often physiologically and morphologically immature. Surfactant deficiency in immature lungs triggers a cascade of alveolar instability and collapse, capillary leak edema, and hyaline membrane formation. The term respiratory distress syndrome (RDS) has come to represent the clinical expression of surfactant deficiency and its nonspecific histologic counterpart, hyaline membrane disease. Historically, chest radiographs of infants with RDS predictably demonstrated decreased pulmonary expansion, symmetric generalized reticulogranular lung opacities, and air bronchograms. Refinements in perinatal medicine, including antenatal glucocorticoid administration, surfactant replacement therapy, and increasingly sophisticated ventilatory strategies have decreased the prevalence of RDS and air leak, altered familiar radiographic features, and lowered the threshold of potential viability to a gestational age of approximately 23 weeks. Alveolar paucity and pulmonary interstitial thickness in these profoundly premature neonates impair normal gas exchange and may necessitate prolonged mechanical ventilation, increasing the risk of lung injury. Bronchopulmonary dysplasia (BPD), alternatively termed chronic lung disease of infancy, is a disorder of lung injury and repair originally ascribed to positive-pressure mechanical ventilation and oxygen toxicity. Before the advent of surfactant replacement therapy, chest radiographs of infants with classic BPD demonstrated coarse reticular lung opacities, cystic lucencies, and markedly disordered lung aeration that reflected alternating regions of alveolar septal fibrosis and hyperinflated normal lung parenchyma. In the current era of surfactant replacement, BPD is increasingly a disorder of very low-birth-weight neonates with arrested alveolar and pulmonary vascular development, minimal alveolar septal fibrosis and inflammation, and more subtle radiographic abnormalities.

Lung epithelial branching program antagonizes alveolar differentiation

“…1) may provide new insights to mechanisms and therapies of lung defects in premature birth. This transition is interrupted by premature birth, especially in very/extremely low birth-weight infants born at the canalicular stage of lung development (gestation week 24 in humans and E17 in mice) (44,45). Interruption to this transition may lead to not only cellular immaturity as a result of insufficient alveolar differentiation, but also structural immaturity as a result of incomplete branching morphogenesis.…”

Brain Natriuretic Peptide: A Predictor for Severity Respiratory Distress Syndrome in Newborns

“…In premature infants, alveolar vessels as well as lungs are not fully developed and they are not able to cope with the quick changes such as increased arterial O2 and gaseous transfer during the first minute of life (13). Therefore, it causes volume overload and increased pulmonary vascular resistance as well as decrease in the systematic resistance which in return result in RDS (14). Some infants sickening to RDS possess a clinically significant shunt of PDA which is left open due to hypoxia, acidosis, secondary lung pressure increase in response to contraction of pulmonary venous pressure, systemic hypotension, immaturity and local secretion of prostaglandins due to the duct dilation; so it seems as if there is a relation between duct patency, airway inflammation and brochopulmonary dysplasia (BPD) (15,16).…”

Diagnostic imaging Comparative analysis of imaging examinations of the thoracic cage in neonates. Defining indications for cat scanning

“…However, in this area also, its role changes with the progress in neonatology; on one hand, it is limited to cases where monitoring respiratory and biochemical parameters is insufficient for the evalu-Comparative analysis of imaging examinations of the thoracic cage in neonates. Defining indications for cat scanning ation of the seriousness of the patient's condition, while on the other, the increased survival rate of preterm infants with a lowered survival threshold after childbirth of 23 weeks of gestational age [1] causes an increased requirement for roentgenographic examination.…”