[Beta 2 stimulants in the therapy of childhood asthma].

Bronchial obstruction, chronic or acute, is due to different anatomical and functional events, mainly to smooth muscular contraction and oedema and secretions. In the first age of life the secretions and thickness of bronchial wool are the most important factors due to small bronchial caliber and poor muscular component. In the older child the most important cause is determined by the reactive spasm of bronchial smooth muscle.