Richard R. MacMahon, Ph.D.
Just what is asthma? It is a "disease that is characterized by increased responsiveness of the trachea and bronchi to some type of trigger that causes widespread narrowing of the airways that changes in severity either as a result of treatment or spontaneously." (Kupstas Soo, 1999). This definition is not entirely clear. Let us explore this in more detail.
Asthma is an increased response by the trachea and bronchi to "some type of trigger"? What are these triggers? In a word - irritants, mostly foreign proteins or allergens (Kovesi, 1996; 1996a; Asthma Triggers, 1999). The body's response is an immune system allergic response. White blood cells, including lymphocytes and eosinophils, are found in large concentrations at the bronchiolar sites of invasion. And these white blood cells seem to marshal the body's defenses. The result is an inflammatory response followed by constrictions of the bronchioles. (Boushey and Fahy, 1995).
The body has a number of responses to foreign proteins and other irritants. In the respiratory passages, especially the bronchioles, these may be collectively termed asthma. The asthma response is inflammation of the bronchiolar lining followed by spasmodic constrictions of the bronchioles plus secretion of thick, ropey mucus. Some of the more common irritants that trigger asthma include animal dander, specific plant proteins, tobacco smoke, house mites and cockroach waste. There is a long list of irritants that could be included as well, among them pesticides, byproducts of various manufacturing processes, and many common household chemicals.
Bronchioles may dilate as a result of medication or from natural recovery. The longer a person suffers from asthma, the less likely it is that the bronchioles will fully recover. Those people with asthma during childhood have a chance as they grow to be an adult, and as their airways reach adult size, to make a full recovery from asthma. Thus the teenage years become of critical importance. But only about 25% of children who suffer from asthma seem to reach a full recovery as adults. Those people who continue to suffer into their adult lives seldom reach complete recovery. (Boushey and Fahy, 1995). A further comprehensive discussion of asthma basics can be found at Allergy, Asthma & Immunology Online (1998) and at a number of other sources (JAMA, 1997b; Kovesi, 1996b; 1996c; 1996d). These articles are written for the general public, at a basic level. They do not explore the asthma immune mechanisms.
A Few Vital Statistics:
-
____
• Asthma is the #1 cause of school absences caused by chronic disease
-
-
____
• Asthma is the seventh-ranked chronic disease in the U.S.A.
-
-
____
• About 5% of the population lives with asthma, although this percentage may be much higher under some conditions
-
-
____
• Children spend approximately 50% of their time in their bedrooms, the most common site of irritation
-
-
____
• Asthma costs the country $9.5 billion annually
-
-
____
• An estimated 12.4 million Americans have asthma. Of these, 4.2 million are under the age of 18
-
-
____
• The prevalence rate of pediatric asthma (rate per 1000 children) rose from 40.1 in 1982 to 63.4 in 1992
-
-
____
• Children of smokers are twice as likely to develop asthma as children of non-smokers
-
-
____
• Only about 25% of the children outgrow the asthmatic condition when their airways reach adult size
-
-
____
• In the U.S.A. there were 4,964 deaths from asthma recorded in 1992. Blacks represent 12% of the population, but account for 21% of these deaths from asthma
-
-
____
• In 1989 there were 479,000 hospitalizations with asthma as the first listed diagnosis. From 1979-1989 asthma hospitalization for children under 15 increased 56% (Am. Lung Assoc. of Ohio, 1995)
