Asthma symptoms are produced by reversible narrowing of the airway, which increases resistance to airflow and consequently reduces the efficiency of movement of air to and from the alveoli. In addition to airway obstruction, cardinal features of asthma include inflammation and hyperreactivity of the airway. In contrast to chronic obstructive pulmonary disease (emphysema and chronic bronchitis), the airway obstruction associated with asthma is generally reversible. However, severe long-standing asthma changes the architecture of the airway. These changes, including smooth muscle hypertrophy and bronchofibrosis, can lead to an irreversible decrement in pulmonary function. These structural changes are limited to the airways. The lung parenchyma is generally spared.
An aberrant immune response associated with allergy appears to underlie asthma in most children over age 3 years and in most young adults; allergy-induced asthma is also known as extrinsic asthma. In contrast, a large number of patients, especially those who acquire asthma as older adults, have no discernible immunolog-ical basis for their condition, although airway inflammation remains a characteristic of the disease; this type of asthma is termed intrinsic asthma. Other patients may have both allergic and nonallergic forms of asthma.
Was this article helpful?
Do You Suffer From ASTHMA Chronic asthma is a paralyzing, suffocating and socially isolating condition that can cause anxiety that can trigger even more attacks. Before you know it you are caught in a vicious cycle Put an end to the dependence on inhalers, buying expensive prescription drugs and avoidance of allergenic situations and animals. Get control of your life again and Deal With Asthma Naturally