Basic Science and Pathohysiology

Asthma is a disorder of the airways that is complex and still not fully understood. However, it is characterised by:

• Bronchial hypersensitivity
• Broncho-constriction
• Bronchial inflammation
• Recurring symptoms of reversible airway obstruction that vary in severity

A large number of cells and mediators have been implicated in the airway inflammation pathway, including the following:

• Eosinophils
• Mast cells
• Leukotrienes
• Prostaglandins
• T-lymphocytes
• Macrophages
• Adhesion molecules

Increased mucous secretion and bronchial oedema also contribute to airflow obstruction. Chronically, desquamation of the epithelium and smooth muscle hyperplasia may result in airway re-modelling [3].