New Insights in Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a 1 out of 2500 live-born disease with a persistent 30-40% mortality rate, consecutively to severe pulmonary hypoplasia and hypertension. The etiology of CDH remains unknown, although recent studies have identified genes potentially involved. The classical view that unclosure of pleuroperitoneal canals is responsible for the occurrence of CDH has been challenged by recent work in transgenic mice. Recent studies on the pathophysiology of CDH provided a closer evaluation of formerly debated pulmonary consequences, especially for alveolarization and surfactant production. Recent advances in prenatal ultrasonography have largely improved the determination of prognosis, allowing reliable evaluation of pulmonary hypoplasia to be achieved through the simultaneous use of Lung-over-Head Ratio, liver position, and/or fetal lung volume measured by 3D ultrasound and MRI, although it remains difficult to predict the functionality of CDH lungs. Open fetal surgery to correct the diaphragmatic defect has been abandoned, but fetal tracheal occlusion used to force lung expansion and growth, after a number of pre-clinical studies in animals, has been applied to the human fetus with encouraging results. Last, post-natal care of CDH neonates was also improved with the use of high-frequency ventilation and vasodilators, particularly inhaled nitric oxide.