Congenital Diaphragmatic Hernia and Diaphragmatic Eventration

Abstract

Congenital diaphragmatic hernia (CDH) is a group of conditions characterised by developmental defects in the diaphragm. The cause is disordered embryogenesis, resulting in incomplete fusion of elements giving rise to the diaphragm. The diagnosis can be made in the antenatal period and can present in the early postnatal period with respiratory distress. Associated lung, vascular, and cardiac abnormalities (including pulmonary hypotension, pulmonary hypertension and increased pulmonary vasculature reactivity) lead to a high mortality (almost 50% overall), and prompt neonatal management is the most important influence on outcome. In this regard, surgical correction has become a nonurgent secondary intervention. Chromosomal abnormalities are found in 5–30% of cases (trisomy 18 and 13 are the most common). CDH can present outside the neonatal period in patients with minimal physiological compromise. The mortality is negligible in this naturally selected group. Eventration of the diaphragm is defined as an abnormal elevation of an otherwise intact diaphragm due to poor or absent musculature. Although some of the mechanical effects are similar to those of CDH, the incidence of pulmonary hypertension is low, and the degree of associated pulmonary hypoplasia is minimal. Thus, the presentation is less dramatic and usually somewhat delayed, and the outcome is significantly better.