Image: STEVE KAGAN, M.D.
Asthma is an eminently controllable illness. Indeed, for most sufferers, control is so effective that it amounts to a virtual cure. But asthma is not curable in the same way as, say, a bacterial pneumonia; it never entirely goes away. Also, no one cure would ever suffice. It is becoming increasingly clear that there many types of asthma--and they differ greatly in their presentation and genesis. For example, asthma that presents as a chronic cough, the "cough variant of asthma," appears to be very different from the life-threatening variety, which results in extreme respiratory failure and sometimes death.
Nevertheless, the sine qua non of asthma--as we understand it today--is the increased sensitivity of the airways to many different agents. These agents include respiratory viruses (common cold virus), pollutants (ozone and cigarette smoke), airborne allergens (animal dander, pollens and molds) and exercise, especially in a cold and dry environment. These agents, called triggers, induce an inflammatory reaction in the airways that, in turn, results in the common symptoms of cough, wheezing, increased mucus production and shortness of breath. Successful control of asthma entails controlling the inflammation in the airways and reversing the symptoms before they get out of hand.
The greatest advances in controlling asthma may be the change in physicians' attitudes toward using preventive medications, as well as attempts to make home rescue plans more aggressive and self-sufficient. The availability of selective and potent medications has made such changes possible. By avoiding known triggers in the environment, such as cigarette smoke, dust mites, roach antigens and dander from warm-blooded pets like cats and dogs, patients can help minimize airway inflammation. Also, newer, tighter and more energy-efficient homes, forced-air heating and wall-to-wall carpeting all contribute to higher levels of indoor triggers.
Another effective strategy for preventing inflammation is the use of certain medications either daily during a season (for most individuals with asthma, it is the fall season), during multiple seasons or year-round. One class of these medications stabilizes the mast cell, (large cells filled with potent inflammation-inducing chemicals called leukotrienes), which line the respiratory tract and play a central role in allergy-induced asthma. These mast cell-stabilizing inhalants include Cromolyn and Nedocromyl. Cromolyn is of particular interest as it is derived from the plant Ammi Visnaga, long used by American Indians as an herbal remedy for colic.
An exciting new class of oral medications, called leukotriene modifiers, neutralize the actions of leukotrienes. This class of medication is the first new class to become available for asthma management in the past 20 years and holds great promise. It includes Zafirlukast, Pranlukast and Zileuton. The most effective preventive medications for asthma belong to the family of corticosteroids. These inhaled medications are delivered either via pressurized canisters or dry powder dispensers and include Beclamethasone, Triamcinolone, Flunisolide, Budesonide and Fluticasone. Their widespread use is the single most important reason for the improved control of asthma in recent decades. Because these medications are applied directly to the surface of the airways through inhalation--and so do not affect other parts of the body as they might if taken orally--their side effects are minimized.
Another attitudinal advance in managing asthma has been the early and aggressive use of symptom relief medications, including Beta-2 receptor stimulants and short courses of oral steroids, as a part of the home rescue therapy. This form of therapy has the additional advantage of making patients and caregivers self-sufficient and confident in handling an acute episode of asthma. This type of self-sufficiency is essential in the successful control of any chronic illness. And the good news on this front is that a second class of Beta-2 medications (essentially more selective optical isomers of their parent medications) has just become available.
The past few years have also seen a concerted effort by the National Institutes of Health, especially the National Heart, Lung, and Blood Institute, and other agencies to educate physicians in the best ways to manage asthma. Community education programs, support groups and the Internet have played a major role in providing useful information to parents of asthmatic children and patients alike.
In summary, the therapeutic and attitudinal advances in managing asthma have been very substantial in the past 15 to 20 years, resulting in more effective and safer ways of controlling it. Although a cure is not on the horizon, nearly complete control is well within reach.