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].