Airway Obstruction

Symptoms of airway obstruction include chest tightness, cough, and wheezing. Airway obstruction can be caused by multiple factors including airway smooth muscle constriction, airway edema, mucus hypersecretion, and airway remodeling. Airway smooth muscle tone is maintained by an interaction between sympathetic, parasym-pathetic, and nonadrenergic mechanisms. Acute bronchoconstriction usually results from mediators such as histamine, cysteinyl leukotrienes, prostaglandins, and tryptase released or generated during degranulation of mast cells and basophils.1 Inflammatory mediators such as histamine, leukotrienes, and bradykinin increase microvascular permeability leading to mucosal edema, which causes the airways to become more rigid and limits airflow.11 These changes exaggerate the consequences of acute bron-

choconstriction. In asthmatics, there is an increased number and volume of mucous

glands, with increased mucus secretion. Extensive mucus plugging may be a cause of persistent airway obstruction in acute severe attacks.

Although airway obstruction in asthma is generally reversible, some asthmatics have an irreversible or fixed obstruction. Airway remodeling is the term used to describe the process that produces the structural airway changes leading to this fixed obstruction; it is characterized by airway epithelial damage, subepithelial fibrosis, airway smooth muscle hypertrophy, increased mucus production, and increased vascularity of the airways.1, 2 These changes increase airflow obstruction and airway responsiveness and may decrease patient responsiveness to therapy.1

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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