Pathophysiology/Differential Diagnosis (Congenital Diaphragmatic Hernia/Respiratory Distress Syndrome=RDS)

The differential diagnosis of congenital diaphragmatic hernia and of the respiratory distress syndrome may be grouped into five different pathophysiological mechanisms, with each one having several pathologies. 1. Valve mechanism of the bronchial system: The exchange of air of a part of the lung is insufficient; due to a hindered backflow the involved part of the lung is overinflated, the exchange of gases insufficient, and the non-involved parts of the lung are compressed. 2. Compression of the lung: Space-occupying processes and lesions displace the normal lung and block the exchange of gases. 3. Hypoplasia of the lung: There are uni- or bilateral hypoplasias, such as isolated anomalies or - more frequently - combined pathologies in diaphragmatic hernia (Bochdalek's hernia). 4. Obstruction of the upper airways: Congenital malformations and tumors may lead to an occlusion of the upper respiratory tract due to functional disturbances or compression. 5. Aspiration into the lung and distention of the abdomen: Aspiration may occur if saliva or food cannot be swallowed; or, in case of vomiting, by overflow into the respiratory airways. An abdomen which is distended after obstructed intestinal passage impairs - besides a possible aspiration - the respiration by the high level of the diaphragm.