Congenital diaphragmatic hernia

What it is

Congenital diaphragmatic hernia (CDH) comes from impaired development and/or fusion of embryonic structures — the pleuroperitoneal membrane — which leads to a persistent defect in the diaphragm during fetal development. Abdominal contents are displaced into the pleural cavity, and the compression of lung tissue leads to pulmonary hypoplasia. That hypoplasia, not the hernia itself, is what matters most.

Left-sided postero-lateral diaphragmatic defects (Bochdalek hernias) are the most common; anterior defects (Morgagni hernias) follow. Approximately 50% of babies with CDH have additional congenital malformations.

How it presents

It is one of the DDx of respiratory distress in a term infant, alongside transient tachypnoea of the new-born (the commonest of them), meconium aspiration, pneumonia, pneumothorax and persistent pulmonary hypertension of the new-born.

The respiratory symptoms are respiratory distress with nasal flaring, tachypnea, cyanosis, intercostal retractions and grunting. The physical findings are:

• Barrel-shaped chest.
• Scaphoid abdomen, a concave anterior abdominal wall.
• Bowel sounds auscultated in the chest.
• Absent breath sounds on the ipsilateral side.
• Shift of heart sounds and apex beat to the right side.

In the neonatal period the other presentation is failure to respond to resuscitation. Possible syndromic dysmorphism may go with it: craniofacial abnormalities, spinal dysraphism, cardiac anomalies.