Asthma, a condition whose incidence, prevalence and mortality rate has been increasing during the past several years, is a very serious health problem for both children and adults. Approximately 12 million adults and children now have asthma in the United States. Nearly 5,000 of them die of it every year. According to the Centers for Disease Control and Prevention, the death rate from asthma increased by 46% from 1970 to 1987 and it is still growing. Asthma-related health costs were estimated to be $6.2 billion dollars annually as of 1990.
In this article, I will describe the pathology of asthma and how it is generally treated by conventional medicine. Then I will discuss the shortcomings of this conventional approach by outlining how a complementary physician might approach the asthma patient. In doing so, I will emphasize how to prevent asthma attacks by working on one's environment, lifestyle and nutritional supplements.
Asthma is a disease that affects a person's ability to breathe. It is a chronic lung disease characterized by airway obstruction that is reversible (but not always completely so), airway inflammation, which results from edema or swelling in the lining of the bronchial tubes, and increased airway responsiveness to a variety of stimuli. The symptoms of an asthma attack include wheezing, shortness of breath and coughing. Breathing out is particularly difficult during an asthmatic attack and wheezing during expiration is particularly characteristic. Asthma may be periodic with relatively symptom free intervals or it may be relatively chronic with mild to moderate symptoms present most of the time. Either type of patient may have a severe acute life-threatening attack, which may require potent drugs in a hospital setting.
Asthma attacks may be triggered by a variety of stimuli, the nature of which varies from individual to individual. Upper respiratory infections, either viral or bacterial, often trigger an asthmatic attack. Exposures to tobacco smoke, perfumes, paints or other strong chemical odors are often culprits. Changes in weather or temperature, exposure to molds, animal danders, grass or tree pollens are all triggers for some asthmatic patients. For some patients, exposure to sulfites, used to preserve foods, has resulted in deaths due to asthma. Certain food colorings, such as the yellow dye tartrazine, as well as many other food additives may be triggers. Drugs, such as aspirin, non-steroidal anti-inflammatory drugs-like Advil, beta blockers-like Inderal, ACE inhibitors and many others can precipitate an asthma attack.
Diagnosis of Asthma
Aside from the clinical observations of shortness of breath, coughing and wheezing, how can asthma be diagnosed? In addition, to hearing the wheeze with a stethoscope, one can use two medical instruments to help with the diagnosis and response to treatment. The first is called a spirometer. Spirometry involves the patient taking a deep breath and blowing into the tube of the spirometer as hard and as fast as he can. The patient may also breathe in and out several times into the tube for additional information. The spirometer measures the amount of air expired and how much is expired at different phases of the expiration. With asthma, we'll see a reduced total amount of air expired or forced vital capacity. We'll also see a reduced volume expired during the first half second and second or forced expiratory volume 0.5 and 1.0. Finally, we'll observe a reduced volume during the middle cycle of the expiration. Each one of these measurements can be improved after the person breathes a bronchodilator drug, thus showing that these changes are at least partially reversible. This reversibility leads one to the diagnosis of asthma rather than a more fixed irreversible lung disease. Another instrument useful in monitoring the severity and response to treatment in asthma patients is a peak flowmeter. Again, the person expires a deep breath as quickly and completely as possible and the peak flow is measured. This instrument is important for monitoring treatment response.
Mechanisms of an Asthma Attack
Now, lets discuss the mechanisms of an asthmatic attack. What happens to the lungs during such attack? First, we see bronchial spasm and/or constriction of the smooth muscles of the bronchi or airway tubes, leading to a narrowing of these passages. Second, we get inflammation and edema or swelling of the inner lining of the bronchi, which further narrows the airways. Third, we observe increased mucus production with the development of mucus plugs that may further block air from getting to the little air sacs in the lungs, thus preventing oxygen from getting into the bloodstream and carbon dioxide from leaving the bloodstream in order to leave the body. And, finally, we frequently see evidence of allergic phenomena on a cellular level, with allergy cells called eosinophils, resulting in further inflammation of the airways. This allergic mechanism almost always involves the substances known as platelet activating factor or PAF and histamine, to a lesser extent. In addition to causing inflammation, this allergic reaction also contributes to bronchial hyper responsiveness.
To review, the important mechanisms of asthma are: 1) an increased responsiveness of the airways to a variety of stimuli; 2) a narrowing of those airways due to a contraction of the smooth muscles of the bronchi; 3) a further narrowing due to inflammatory changes in the walls of the bronchi; and 4) an increased production of mucous and fluids in the airways causing further narrowing and even blockage.
These mechanisms are important to keep in mind as we discuss both conventional and complementary treatments.
Conventional Treatment Approaches to Asthma
A good conventional approach to asthma will look at the environmental stimuli that set off a response from the super sensitive airways. Here, a careful medical and ecologic history is most important to establish which stimuli are most important for this particular patient. Do asthma attacks occur mostly indoors or outdoors? If indoors, are they worse at home or at work? Are they worse during a particular season? Tree pollens, for example, are very high in early spring, grass pollens peak in the late spring and the classic ragweed season begins in late summer and ends with freezing weather. Sometimes asthma attacks are precipitated by exercise.
Patients will be warned about the adverse effects of active or passive tobacco smoke. They may also be advised to avoid dust or fumes of chemicals, exposures to people who have upper respiratory infections, cold air, known inhalant allergens such as cats or dogs, grasses or pollens and various drugs such as the beta blockers, ace inhibitors, aspirin and certain non-steroidal anti-inflammatory drugs. Once allergens have been identified, measures recommended to minimize exposure to them might include avoiding outdoor activities in early morning when allergen levels are highest, keeping windows closed as much as possible during the peaks of allergy seasons and keeping indoor humidity levels between 40 and 50 percent to reduce pollen and mold exposure. Eliminating carpeting and upholstery when possible and using plastic pillow and mattress casings will help to keep dust exposure to a minimum. Laundering bedclothes weekly in hot water is also recommended. High efficiency particulate air, abbreviated HEPA filtering devices, effectively reduce airborne allergens and other inhaled irritants.
Occupational exposure must be explored as more than 200 different occupational asthma triggers have been reported in the medical literature. The concept of total body burden of toxic and allergy factors is very important here. To prevent and treat asthma attacks, the goal is to reduce exposure to toxic and allergenic substances as much as possible to lower the total body burden.
Use of Bronchodilator Drugs by Conventional Physicians to Manage Asthma
Frequently, an asthma attack may be precipitated by a bacterial infection. In such a case, an antibiotic medication is helpful in clearing up the infection. During severe attacks, respiration may be limited so much that the oxygen concentration in the bloodstream may be dangerously low. Breathing in oxygen will help to correct this situation. Aside from oxygen and antibiotics, the medications to treat both acute and chronic asthma are classified into two categories, bronchodilators and anti-inflammatory agents. Together, these medications are used to reverse or prevent air flow obstruction. The smooth muscles of the airways contain receptors that are known as beta 2-adrenergic receptors. Upon stimulation, these receptors cause a relaxation of the smooth muscles of the bronchi.
A hormone in our body that stimulates this type of receptor is adrenaline or epinephrine, which is the fight or flight hormone secreted by the adrenal medulla. The drugs used to stimulate these receptors are called beta 2- adrenergic agonists. One of the most used of these drugs is albuterol whose brand names are Proventil or Ventolin. They are administered mostly by metered dose inhalers (abbreviated MDI). For severe attacks, albuterol may be administered in the hospital by nebulizer every one or two hours. However, the frequency is reduced as soon as possible, and the patient is switched to the metered dose inhaler. Outside of the hospital the medication is used as necessary, preferably only one or two puffs daily. It may be used prior to exercise to prevent an exercise induced asthmatic attack.
Although the product literature states that up to 12 puffs a day may be used, patients with mild asthma should need these drugs only 3 or 4 time a week. A pattern of regular or increasing use approaching 8 to 12 puffs a day reflects poor asthma control and warrants immediate re-evaluation. Although these beta 2-adrenergic agonists are reported to be reasonably safe, they do stimulate the autonomic nervous system and may produce rapid or irregular heartbeat, insomnia, shakiness and nervousness.
Anti-cholinergic agents constitute the second class of bronchodilators. Whereas the beta 2-adrenergic agonists mimic the sympathetic nervous system, the anti-cholinergic agents work by inhibiting the parasympathetic nervous system as the latter tends to constrict the bronchi. So by inhibiting the action of the parasympathetic nervous system with anti-cholinergic drugs like ipratropium bromide or Atrovent, bronchodilation is promoted. Atrovent is also given by inhaler. Potential adverse effects include dry mouth, cough, headaches, a worsening of glaucoma and urinary retention.
A third class of bronchodilators are the methylxanthines, such as aminophylline and theophylline. Caffeine is another example of a methyl xanthine, although it is not used in asthma. The exact mechanisms of action of the methylxanthines in causing bronchodilation is unclear. Previously, these drugs had been considered the first line of therapy for asthma, but because of their serious side effects, they are somewhat less important at the present time. However, aminophylline or theophylline may be used intravenously if other treatments have not gotten an attack under control.
For chronic asthma, theophylline, whose brand names include Theo-Dur, Uniphyl, Slo-bid and others, is now considered a third-line choice, but may be of benefit in nighttime asthma, due to its long duration of action. Adverse effects of theophylline involve many organ systems. They may be mild or severe and life threatening. Gastrointestinal symptoms include heartburn, nausea and vomiting. Central nervous system negative side effects include headaches, insomnia, tremor and seizures. And finally abnormal heart rhythms and deaths have been reported.
Some studies have shown that frequent over use of the bronchodilators may result in an overall worsening of the asthma condition. This effect and the adverse effects on the cardiovascular system may explain in part the increasing death rate from asthma during the past several years. In other words, increasing mortality from asthma may be partially iatrogenic, or in other words, doctor caused.