Autopsy data are lacking, and no animal model exists. Some children with tracheomalacia have the lesion due to vascular anomalies or other causes of compression of the airway. Others have tracheomalacia as a residua of repair of a tracheoesophageal fistula. In the latter case, a history of surgery should exist. Tracheomalacia may coexist with and complicate other disorders, including cystic fibrosis and bronchopulmonary dysplasia.
Some infants have evidence of coexisting airway hyperreactivity.
Diagnosis often can be confirmed by fluoroscopy of the airway. During the study, the radiologist observes the airway collapsing and opening up. This may be suggested by the anteroposterior films, in which the tracheal air shadow seems to disappear and reappear with respirations in the affected area of the trachea. The lesion may be observed more easily on lateral films, where the anterior and posterior walls of the trachea may be observed apposing dynamically. A static collapse of the airway is suggested by loss of the tracheal air shadow with no respiratory changes.