Tracheomalacia can be associated with a variety of congenital anomalies, including cardiovascular defects, developmental delay, esophageal anomalies, and GER. It can be caused by a diffuse process of congenital origin or by a localized abnormality such as a vascular ring, anomalous innominate artery, esophageal atresia, and tracheoesophageal fistula. Internal compression by an endobronchial or tracheostomy tube also may be the culprit. Tracheal cartilage deficiency may be present in 75% of the patients with tracheoesophageal fistula. Tracheomalacia rarely is found in combination with laryngomalacia.
The entire cartilaginous structure of the upper airway is diffusely involved in congenital abnormality, or a localized area of decreased rigidity may be observed secondary to abnormal development of foregut and vasculature in embryonic life. A vascular ring around the trachea does not allow normal development in that area of trachea, and tracheomalacia is observed in the area of impingement.
The cases of acquired tracheomalacia occur with increasing frequency both in children and in adults, and the tracheomalacia often is not recognized clearly. These lesions usually cause focal tracheomalacia and may result from indwelling tracheostomy and endobronchial tube, chest trauma, chronic tracheobronchitis, and inflammation (relapsing polychondritis). They may be secondary to pulmonary resection and tracheal malignancy (cylindroma), and they may be idiopathic.
A. Primary (congenital) tracheomalacia or idiopathic – due to an intrinsic abnormality in the wall of airway. It may be classified as follows :
B. Secondary (acquired) adult tracheomalacia may be classified as follows :