Congenital diaphragmatic hernia (CDH) is a developmental defect of the diaphragm that allows abdominal viscera to herniate into the chest. The volume of herniated contents may be small or large enough to contain most of the gut, spleen, or liver. Because herniation occurs during a critical period of lung development when bronchial and pulmonary artery branching occurs, lung compression by the herniated bowel results in pulmonary hypoplasia. With increasing severity of lung compression, there is a corresponding decrease in the bronchial branching, resulting in a reduction of generations of bronchi and lung tissue. Pulmonary hypoplasia is most severe on the ipsilateral side but may also occur on the contralateral side if the mediastinum shifts and compresses the contralateral lung. In addition, arterial branching is reduced and there is muscular hyperplasia of the pulmonary arterial tree . Biochemical analysis also indicates there is a secondary surfactant deficiency [2-4]. (See "Congenital diaphragmatic hernia: Prenatal diagnosis and management".)
CDH is estimated to occur in 1 out of 2200 births. Affected neonates usually present in the first few hours of life with respiratory distress that may be mild or so severe as to be incompatible with life. With the advent of antenatal diagnosis and improvement of neonatal care, survival has improved, but there still remains significant risk of death and complications in infants with CDH.
The clinical manifestations, diagnosis, and management of the neonate with CDH will be reviewed here. The pathogenesis, anatomy, and the prenatal diagnosis and management of CDH are discussed separately. (See "Congenital diaphragmatic hernia: Prenatal diagnosis and management".)
Infants with congenital diaphragmatic hernia (CDH) most often develop respiratory distress in the first few hours or days of life. The spectrum of presentation can vary from acute, severe respiratory distress at birth, which is common, to minimal or no symptoms, which is observed in a much smaller group of patients.
Physical examination will reveal a barrel-shaped chest, a scaphoid appearing abdomen because of loss of the abdominal contents into the chest, and absence of breath sounds on the ipsilateral side. In most patients with CDH (because the lesion is on the left side), the heartbeat is displaced to the right because of a shift in the mediastinum.