Asthma Health Article

Physical examination

Apart from listening to the patient's chest, the examiner should look for maximum chest expansion while taking in air. Hunched shoulders and contracting neck muscles are other signs of narrowed airways. Nasal polyps or increased amounts of nasal secretions are often noted in asthmatic patients. Skin problems like atopic dermatitis or eczema indicate that the patient has allergic problems. A family history of asthma or allergies can be a valuable indicator. The diagnosis may be strongly suggested when typical symptoms and signs are present.

Spirometry and chest x ray

Spirometry can confirm a diagnosis of asthma by measuring lung function: how much air the lungs can hold and how much they can expel. Asthma patients typically have normal lung volumes with diminished flow rates. Repeating the test after the patient inhales a bronchodilator will show whether the airway narrowing is reversible, a finding that distinguishes asthma from other obstructive diseases like emphysema.

Often patients use a related instrument, called a peak flow meter, to monitor asthma severity at home. Because this device measures the strength with which air is exhaled, it can detect narrowed airways at the earliest stage, before an attack becomes full blown. This allows the patient to take the appropriate medication and diminish or avoid the episode.

Determining what triggers asthma attacks can be difficult. Skin testing may be helpful, although an allergic skin response does not necessarily mean that the allergen being tested is causing the asthma. Once a specific allergen is suspected, a blood test can be run to check for IgE antibodies, since the immune system always produces an antibody in response to an allergen. This will show if the patient is sensitive to a particular allergen. If the diagnosis is still in doubt, the patient can inhale a suspect allergen while using a spirometer to detect airway narrowing, a test called "allergen challenge." Spirometry may also be repeated after a bout of exercise to confirm or refute the diagnosis of exercise-induced asthma. A chest x ray may help to rule out other pulmonary disorders, or confirm findings particular to asthma.

Treatment

Patients should be examined periodically and have their pulmonary function measured by spirometry to ensure that treatment goals are being maintained. The goal is to prevent troublesome symptoms, maintain lung function as close to normal as possible, and allow patients to pursue their normal activities, including those requiring exertion. The best drug therapy is that which controls asthmatic symptoms while causing few or no side-effects.

Drugs

METHYLXANTHINES. The chief methylxanthine is theophylline. It may exert some anti-inflammatory effect, and is especially helpful in controlling nighttime asthma. When, for some reason, a patient cannot use an inhaler to maintain long-term control, sustained-release oral theophylline is a good alternative. The blood levels of the drug must be measured periodically, as too high a dose can cause an abnormal heart rhythm or convulsions.

BETA-RECEPTOR AGONISTS. These bronchodilators, such as albuterol, are the best choice for relieving sudden attacks of asthma and for preventing attacks triggered by exercise because they relax the smooth muscles in the lungs. This prevents bronchospasm but doesn't help the swelling that often accompanies an asthma attack. These drugs are effective within about 30 minutes, and are maximally effective for three or four hours. They may be taken by mouth, inhaled, or injected, although the oral forms often produce such side effects as jitters and sleeplessness.

STEROIDS. Steroids and corticosteroids block inflammation and are extremely effective in relieving asthma symptoms. When taken by inhalation for a long period, they reduce the airways' sensitivity to allergens, and asthma attacks become less frequent. This is the strongest medicine for asthma, and can control even severe cases over the long term. Oral or intravenous steroids taken over long periods, however, can cause numerous side effects, including gastric bleeding, loss of calcium from bones, cataracts, and diabetes. Patients on long-term steroid therapy may also have problems with wound healing and weight gain, and may develop mental problems as well. In children, growth may be slowed. Besides being inhaled, steroids may be taken by mouth or injected to control severe asthma rapidly.

LEUKOTRIENE MODIFIERS. Leukotriene modifiers, such as montelukast (Singulair), zileuton (Zyflo), and zafirlukast (Accolate) are drugs that work by counteracting leukotrienes, substances released by white blood cells in the lungs that constrict air passages and promote mucus secretion. They may reduce the need for short-acting inhalers, and may replace inhaled steroid treatment for patients with mild forms of asthma. Leukotrine modifiers may also help asthma patients recover from severe attacks more quickly, and can even help alleviate the allergic rhinitis that often accompanies allergies.

OTHER DRUGS AND TREATMENTS. Cromolyn sodium (Intal) and nedocromil (Tilade) are anti-inflammatory agents that stabilize the airways and help prevent the swelling and inflammation that trigger asthma attacks. They can also prevent flareups when given before exercise or when exposure to an allergen cannot be avoided. Like most asthma medication, these drugs must be taken regularly even if there are no symptoms, and require weeks or months of use before they reach their optimum effectiveness.

Anti-cholinergic drugs, such as ipratropium bromide (Atrovent), are useful in controlling severe attacks when added to an inhaled beta-receptor agonist. They help widen the airways and suppress mucus production. The effects of anti-cholingerics usually last longer than beta-agonists, and are often given in combination with bronchodilators to improve breathing.

If a patient's asthma is caused by an allergen that cannot be avoided and has become difficult to control through drug therapy alone, immunotherapy (allergy shots) may be beneficial. In this treatment, increasing amounts of the allergen are injected over a period of three to five years, so the body can build up an effective immune response. There is a risk that this treatment may itself trigger an asthma attack or even anaphylaxis. Immunotherapy has been used since the early twentieth century to treat allergies and hayfever. New studies have indicated that it also reduces asthma symptoms caused by exposure to such allergens as dust mites, ragweed pollen, and cats.