July 07, 2007

Asthma - Continuation

Diagnosis and Treatment

Physicians typically diagnose asthma by looking for the classic symptoms: episodic problems with breathing that include wheezing, coughing, and shortness of breath. When symptoms alone fail to establish a diagnosis of asthma, doctors may use spirometry, a test that measures airflow. By comparing a patient’s normal airflow, airflow during an attack, and airflow after the application of asthma medication, doctors determine whether the medicine improves the patient’s breathing problems. If asthma medication helps, doctors usually diagnose the condition as asthma.

Identifying the specific trigger of a patient’s asthma is usually more difficult than the initial diagnosis. Triggers may be easily recognizable and consistent; for example, a patient may always develop an asthma attack when using a particular cosmetic or household cleaning product. When the triggers are more difficult to identify, doctors perform a series of allergy skin tests to help determine whether allergy triggers are responsible. Skin tests are not conclusive, however, because patients may have skin reactions to substances that do not necessarily trigger an asthma attack. Doctors may also use spirometry to evaluate a patient’s airflow before and after exposure to common triggers. Triggers that decrease airflow may be responsible for the patient’s asthma.

Although there is no cure for asthma, effective treatment is available for preventing attacks and for controlling and ending attacks soon after they have begun. Asthma medications are taken orally or inhaled in vapor form using a metered-dose inhaler, a hand-held pump that delivers medication directly to the airways. There are two kinds of asthma medications: bronchodilators, which reduce bronchospasm; and anti-inflammatory medications, which reduce airway inflammation.

Bronchodilators are the most widely used medications for controlling sudden asthma attacks and for preventing attacks brought on by physical activity or exercise. They work directly on sites called beta-receptors that are attached to small muscle bands encircling the airways. When these drugs attach to the beta-receptors, the muscles relax and the airway dilates. Theophylline is a bronchodilator that works by relaxing the muscles surrounding the airways.

Anti-inflammatory medications work mainly by interfering with the activity and chemistry of immune cells, such as mast cells, that cause inflammation in the airway walls. Anti-inflammatory medications also help relax the airway muscles that constrict during bronchospasm. Corticosteroids reduce asthma symptoms by suppressing the immune response, and they often succeed when no other asthma treatment works. Over time they reduce the sensitivity of the airways to many common triggers. Long-term use of oral corticosteroids may have severe side effects, including weakening of the bones and the development of cataract, a clouding of the lens of the eye. Recent studies suggest that small doses of inhaled corticosteroids taken in combination with certain bronchodilators may work equally well while significantly reducing the side effects. Leukotriene modifiers, another type of anti-inflammatory medication, are taken orally as an alternative to corticosteroids for the long-term treatment of mild asthma.

Immunotherapy is a treatment option for asthma caused by allergens. This form of therapy modifies a person’s allergic response by repeated exposure to small amounts of allergens. The asthmatic is injected periodically with known allergens, a procedure that trains the asthmatic’s body to react to the allergens differently. Immunotherapy is especially effective in reducing allergic reactions to dust mites, animal dander, pollen, and fungi.

To control asthma attacks before they begin, asthmatics can measure their peak expository flow rate (PEFR), which is a gauge of how fast a person can exhale air from the lungs. By breathing into a small hand-held device called a flow meter, an asthmatic can learn when their airways are first starting to narrow. When the PEFR falls, asthma medication may be needed to prevent an attack. PEFR and medication should be used under a physician’s guidance.

Asthmatics can also prevent and control attacks by limiting their exposure to environmental triggers, especially allergens. Frequently cleaning carpeting, bedding, and household upholstery reduces levels of irritants and allergens in the home. To prevent asthma attacks, asthmatics should wear a mask while cleaning. Regularly bathing pets minimizes levels of animal dander in the air. Asthmatics should take care to avoid pollutants and irritants such as cleaning sprays and cigarette smoke whenever possible. Seasonal allergies to pollen and mold spores can be reduced by avoiding the outdoors during peak periods of activity.

Adapted from: MSN ENCCARTA