Asthma
Asthma is a chronic disease of the lungs and airways that affects an estimated 14 million to 17 million people in the United States. Severe asthma is a serious health concern that can lead to respiratory failure and death. Asthma kills an estimated 5000 people a year in the United States. There are over 470,000 individuals that seek hospital treatment for asthma symptoms.
Despite its prevalence, experts differ in the definition of the disease. Clinical authorities typically favor a broad, comprehensive definition. The National Heart, Lung and Blood Institute, for example, defines asthma as:
"A chronic inflammatory disorder of the airways (which causes recurrent episodes of wheezing, breathlessness, chest tightness and coughing, particularly at night or in the early morning) usually associated with widespread but variable airflow obstruction that is often reversible, either spontaneously or with treatment."
Organizations geared primarily toward the informational needs of patients usually promote, simpler, more "user-friendly" definitions. The American Lung Association, for example, defines asthma as:
"A chronic disease of the lungs in which the airways overreact to certain factors by becoming inflamed or obstructed, making it difficult to breathe comfortably."
Asthma is a condition in which the bronchial tubes in the lungs react to different stimuli by becoming inflamed. These asthma triggers vary and may include exercise, cold air, allergens (such as dust, ragweed, mold, or cat dander), infections, and emotional reactions. Inflammation of the bronchial airways causes them to become constricted and narrowed. This narrowing of the airways, called bronchoconstriction, produces the symptoms: shortness of breath, tightness in the chest, coughing, and wheezing.
Some people suffer asthma symptoms continuously; others experience them only if exposed to triggers. Regardless of the cause, severe asthma is a serious health concern that can lead to respiratory failure and death.
Except in severe cases, symptoms are occasional. The duration and severity of asthma symptoms vary greatly from time to time and from patient to patient. The symptoms may be intermittent, and they can last just a few minutes or days. In severe cases, symptoms may be constant and persistent.
Pharmacological (drug) therapy for asthma has several goals: prevention of chronic symptoms, recurrent exacerbations, emergency room visits, and hospitalization; maintenance of normal lung function and normal activity levels; and avoidance of side effects of other medications. There are two broad classes of medications used in the treatment of asthma: quick-relief, or rescue, medications; and long-term control medications.