LAUSR

To the Editor: Tracheobronchomalacia (TBM) is a type of disorder that is caused by malformation of cartilage; the malformation leads to a deformity of the trachea or bronchus, with a cross-sectional reduction of ≥50% during exhalation, due to primary or secondary reasons. The severity of TBMdepends on the anatomical changes of airways, which are described as mild (50%–75% reduction), moderate (75%–90% reduction), and severe (>90% reduction). According to previous studies, a set of causes have been identified to be associated with TBM. Congenital airway malacia can be a part of many rare syndromes, including chromosomal defect syndromes, de novo genetic mutations, mucopolysaccharidoses, and inherited connective tissue disorders. In addition, some conditions, such as tracheoesophageal fistula, vascular rings, malformation of the cardiovascular system, vitamin D deficiency, and recurrent infections, are revealed as the secondary reasons for TBM. Therefore, for TBM patients, it is important to distinguish the etiologies of TBM, which help to guide therapeutic and nursing strategies.