NCIt definition : A congenital or acquired abnormality of the wall of the bronchi. In congenital cases,
there is lack of rigidity in the cartilage of the bronchial wall. In acquired cases,
the cartilage of the bronchial wall is degenerated, secondary to tracheostomy or presence
of a breathing tube. Symptoms include noisy breathing and wheezing.;
Alternative definition : NICHD: Increased bronchial collapsibility.;