Asthma
Asthma is a chronic inflammatory disorder involving constriction of the muscles lining the bronchial airways. Physical symptoms of asthma include coughing, wheezing, tightness of the chest and shortness of breath. Asthmatic lungs are often referred to as "twitchy" meaning they overreact to stimuli which are harmless to others, including allergens and cold, dry air. During an asthma attack, there are several changes in the bronchial tubes and airways that bring about these symptoms:
- The muscles around the bronchial tubes tighten, causing the airways to narrow. This is known as bronchospasm or bronchoconstriction.
- The already inflamed bronchial tubes become even more swollen.
- Thick mucus is produced within the bronchial tubes.
Causes of Asthma
The prevalence of asthma increased 75% from 1980 to 1994, and currently affects approximately 20 million Americans. Researchers have yet to pinpoint the cause for the increase in asthma. Allergic rhinitis is considered a risk factor in developing asthma, as up to 78% of people with asthma also have allergic rhinitis. It is known that the following triggers play a significant role in provoking asthma attacks:
- allergens such as pollens, molds, animal dander, dust mites and cockroaches;
- irritants such as strong odors and sprays, chemicals, air pollutants, tobacco smoke and cold air;
- viral or sinus infections including colds, pneumonia and sinusitis;
- exercise, especially in cold, dry air;
- gastroesophageal reflux disease (GERD), a condition in which stomach acid flows back up the esophagus;
- medication and foods;
- emotional anxiety.
Diagnosis and Treatment
Allergists follow the national Guidelines for the Diagnosis and Management of Asthma (National Asthma Education and Prevention Program, National Institutes of Health, 1997) to diagnosis and establish treatment plans for patients with asthma and other allergic diseases.
To diagnose asthma, a thorough history is taken and a physical examination is performed, with special attention to the nose and sinuses for evidence of chronic infection. A spirometer is used to objectively measure the amount of air inhaled and exhaled and to determine the level of airway obstruction.
Allergy skin testing is conducted to determine which specific substances trigger asthma attacks. During skin testing, a tiny amount of allergen is scratched across or lightly pricked into the skin. If a person is allergic to a specific allergen, a red bump will appear on the skin.
Although there is no cure for asthma, there are effective treatment methods. Medication therapies are designed to minimize the airway inflammation component of asthma as well as to treat airway narrowing. Environmental control measures are implemented to avoid or eliminate factors that induce or trigger asthma flare-ups. Immunotherapy may also be considered if allergies are known to be an asthma trigger, a condition which is most common in children.
Medication Therapies for Asthma
- Anti-inflammatory agents such as cromolyn or nedocromil limit inflammation in the bronchial tubes. Cromolyn and nedocromil are non-steroidal and usually are prescribed in the inhaled form.
- Corticosteroids are effective anti-inflammatory medications. They are prescribed in both the inhaled and oral form. Oral corticosteroids are generally only prescribed for those with severe asthma symptoms as they can have more side effects than inhaled corticosteroids. Long-term use of oral corticosteroids is not recommended, except in cases of uncontrolled, severe asthma. Corticosteroids are not equivalent to anabolic steroids-the drugs abused by some athletes.
- Anti-leukotrienes or leukotriene modifiers fight potent chemicals within the body called leukotrienes (lu-ko-try-eens). Leukotrienes are responsible for the contraction of the airway smooth muscle, increasing leakage of fluid from cells in the lung, and further promoting inflammation by attracting other inflammatory cells into the airways.
Recently, new anti-leukotriene medications have been introduced to fight the inflammatory response typical of allergic disease. These drugs are used in the treatment of chronic asthma. Recent data demonstrates that prescribed anti-leukotriene medications can be beneficial for many patients with asthma. It is likely that these newer medications will eventually have an increased role in asthma care as more studies are conducted.
- Bronchodilators are generally used as asthma "rescue medications" to relieve coughing, wheezing, shortness of breath and difficulty in breathing. They work by opening up the bronchial tubes so that more air can flow through. Bronchodilators include beta-agonists, theophylline and anticholinergics. They come in inhaled, tablet, capsule, liquid or injectable forms.
Salmeterol is a long-acting bronchodilator that, along with an anti-inflammatory medication, is used for maintenance in the long-term control of asthma symptoms.
