Congenital diaphragmatic hernia

Definition

• Developmental defect of the diaphragm that allows abdominal viscera to enter the chest, resulting in pulmonary hypoplasia, pulmonary hypertension and cardiac strain.

Classification

• In about 95% the defect is posterolateral (Bochdalek hernia), left-sided in about 85% and bilateral in about 2%; Bochdalek hernias are usually the most clinically severe.
• Anterior Morgagni hernias arising from an anteromedial defect are much less common at about 5%.

Aetiopathogenesis

Aetiology and pathophysiology

• Small and large bowel, stomach, liver and spleen may herniate through the defect into the chest; with large hernias the lung on the affected side is hypoplastic, and the contralateral lung may also be affected.
• Underdevelopment of the pulmonary vasculature raises pulmonary vascular resistance and leads to pulmonary hypertension with possible right-to-left shunting through the foramen ovale or a patent ductus arteriosus.
• In about 50% other congenital anomalies are present, particularly heart defects.

Clinical features

• Respiratory distress usually develops in the first hours of life, immediately after birth in severe cases; typical are a scaphoid abdomen and bowel sounds with absent breath sounds over the affected hemithorax, and with smaller defects symptoms may begin only after hours or days.

Diagnosis

• Prenatally the hernia may be detected on ultrasound, and fetal MRI allows additional risk stratification.
• After birth, the radiograph shows stomach and bowel loops in the chest with displacement of the heart and mediastinum to the opposite side; CT and MRI assess defect location, contents and lung volumes, and echocardiography screens for associated heart defects.

Keep learning in the app

Further reading (selection)

1. StatPearls: Congenital Diaphragmatic Hernia (NCBI Bookshelf)
2. MSD Manual Professional Edition: Diaphragmatic Hernia

Cross-references