Bronchial asthma: pathophysiological mechanisms and corticosteroids

The clinical effects in asthma of corticosteroids can be ascribed to their strong anti-inflammatory action. The pathophysiology of asthma is complex. A diversity of mediators and interactions between mediators and between mediators and various cell types enhances and maintains the inflammatory process in the airways resulting in severe asthma. This is a vicious circle. Penetration through the airway epithelium of allergens and other insulting particles trigger release of inflammatory mediators and neurotransmitters, which, by chemotaxis and activation of inflammatory cells, results in enhanced and prolonged mediator release. Several of these mediators possess tissue-toxic properties enhancing the airway inflammation. The glucocorticoids have several points of action affecting both mediator release and accumulation and activation of inflammatory cells, which explains their favourable effect in asthma.