Which of the following events occurs first in the pathogenesis of asthma?

a. destruction of lung tissue
b. airway inflammation
c. bronchodilation
d. loss of lung elasticity

b. The first event that occurs is airway inflammation, which is due to the release of inflammatory mediators (e.g., histamine, prostaglandins, leukotrienes, and other cytokines), triggered by exposure to allergens such as dust, plant pollen, smoke, and animal dander; exercise; stress; changes in weather; and most frequently, upper respiratory viral infection. These inflammatory mediators cause swelling of the airways and provoke contraction of the airway smooth muscle.