<unk>  is a term for weak cartilage in the walls of the bronchial tubes, occurring in children under six months, presented with noisy breathing and/or wheezing. There is collapse of a main stem bronchus, on expiration. There are two types of<unk> . Primary<unk>  is due to a deficiency in the cartilaginous rings. Secondary<unk>  may occur by extrinsic compression from an enlarged vessel, a vascular ring or a bronchogenic cyst.
Bronchomalacia
Tracheomalacia
Tracheal diverticulum
Laryngomalacia
Croup
Bronchiectasis
Alpha 1-antitrypsin deficiency
Hydrothorax