Asthma is an inflammatory disorder of the airways, which causes attacks of wheezing , shortness of breath, chest tightness, and coughing.
See also: Pediatric asthma
Bronchial asthma; Exercise-induced asthma
Causes, incidence, and risk factors:
Asthma is caused by inflammation in the airways. When an asthma attack occurs, the muscles surrounding the airways become tight and the lining of the air passages swell. This reduces the amount of air that can pass by, and can lead to wheezing sounds.
Most people with asthma have wheezing attacks separated by symptom-free periods. Some patients have long-term shortness of breath with episodes of increased shortness of breath. In others, a cough may be the main symptom. Asthma attacks can last minutes to days and can become dangerous if the airflow becomes severely restricted.
In sensitive individuals, asthma symptoms can be triggered by breathing in allergy-causing substances (called allergens or triggers).
Common asthma triggers include:
- Animals (pet hair or dander)
- Changes in weather (most often cold weather)
- Chemicals in the air or in food
- Respiratory infections, such as the common cold
- Strong emotions (stress)
- Tobacco smoke
Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) provoke asthma in some patients.
Many people with asthma have an individual or family history of allergies , such as hay fever (allergic rhinitis) or eczema . Others have no history of allergies.
- Cough with or without sputum (phlegm) production
- Pulling in of the skin between the ribs when breathing (intercostal retractions )
- Shortness of breath that gets worse with exercise or activity
- Comes in episodes
- May be worse at night or in early morning
- May go away on its own
- Gets better when using drugs that open the airways (bronchodilators)
- Gets worse when breathing in cold air
- Gets worse with exercise
- Gets worse with heartburn (reflux)
- Usually begins suddenly
Additional symptoms that may be associated with this disease:
- Abnormal breathing pattern --breathing out takes more than twice as long as breathing in
- Breathing temporarily stops
- Chest pain
- Nasal flaring
- Tightness in the chest
Signs and tests:
Allergy testing may be helpful in identifying allergens in people with persistent asthma. Common allergens include pet dander, dust mites, cockroach allergens, molds, and pollens. Common respiratory irritants include tobacco smoke, pollution, and fumes from burning wood or gas.
The doctor will use a stethoscope to listen to the lungs. Asthma-related sounds may be heard. However, lung sounds are usually normal between asthma episodes.
Tests may include:
- Arterial blood gas
- Blood tests to measure eosinophil count (a type of white blood cell) and IgE (a type of immune system protein called an immunoglobulin)
- Chest x-ray
- Lung function tests
- Peak flow measurements
The goal of treatment is to avoid the substances that trigger your symptoms and to control airway inflammation. You and your doctor should work together as a team to develop and carry out a plan for eliminating asthma triggers and monitoring symptoms.
There are two basic kinds of medication for the treatment of asthma:
- Long-acting medications to prevent attacks
- Quick-relief medications for use during attacks
Long-term control medications are used on a regular basis to prevent attacks, not to treat them. Such medicines include:
- Inhaled corticosteroids (such as Azmacort, Vanceril, AeroBid, Flovent) prevent inflammation
- Leukotriene inhibitors (such as Singulair and Accolate)
- Long-acting bronchodilators (such as Serevent) help open airways
- Omilizumab (Xolair), which blocks a pathway that the immune system uses to trigger asthma symptoms
- Cromolyn sodium (Intal) or nedocromil sodium (Tilade)
- Aminophylline or theophylline (not used as frequently as in the past)
- Sometimes a single medication that combines steroids and bronchodilators are used (Advair, Symbicort)
Quick relief, or rescue, medications are used to relieve symptoms during an attack. These include:
- Short-acting bronchodilators (inhalers), such as Proventil, Ventolin, Xopenex, and others
- Corticosteroids, such as methylprednisolone, may be given directly into a vein (intravenously), during a severe attack, along with other inhaled medications
People with mild asthma (infrequent attacks) may use quick relief medication as needed. Those with persistent asthma should take control medications on a regular basis to prevent symptoms. A severe asthma attack requires a check up by a doctor and, possibly, a hospital stay, oxygen, and medications through a vein (IV).
A peak flow meter is a simple device to measure how quickly you can move air out of your lungs. It can help you see if an attack is coming, sometimes even before any symptoms appear. Peak flow measurements can help show when medication is needed, or other action needs to be taken. Peak flow values of 50-80% of a specific person's best results are a sign of a moderate asthma attack, while values below 50% are a sign of a severe attack.
The stress caused by illness can often be helped by joining a support group, where members share common experiences and problems.
See: Asthma and allergy - support group
There is no cure for asthma, although symptoms sometimes improve over time. With proper self management and medical treatment, most people with asthma can lead normal lives.
The complications of asthma can be severe. Some include:
- Decreased ability to exercise and take part in other activities
- Lack of sleep due to nighttime symptoms
- Permanent changes in the function of the lungs
- Persistent cough
- Trouble breathing that requires breathing assistance (ventilator)
Calling your health care provider:
Call for an appointment with your health care provider if asthma symptoms develop.
Call your health care provider or go to the emergency room if:
- An asthma attack requires more medication than recommended
- Symptoms get worse or do not improve with treatment
- You have shortness of breath while talking
- Your peak flow measurement is 50-80% of your personal best
Go to the emergency room if:
- Drowsiness or confusion develops
- There is severe shortness of breath at rest
- The peak flow measurement is less than 50% of your personal best
- You have severe chest pain
Asthma symptoms can be substantially reduced by avoiding known triggers and substances that irritate the airways.
Bedding can be covered with "allergy proof" casings to reduce exposure to dust mites. Removing carpets from bedrooms and vacuuming regularly is also helpful. Detergents and cleaning materials in the home should be unscented.
Keeping humidity levels low and fixing leaks can reduce growth of organisms such as mold. Keep the house clean and keep food in containers and out of bedrooms -- this helps reduce the possibility of cockroaches, which can trigger asthma attacks in some people.
If a person is allergic to an animal that cannot be removed from the home, the animal should be kept out of the patient's bedroom. Filtering material can be placed over the heating outlets to trap animal dander.
Eliminating tobacco smoke from the home is the single most important thing a family can do to help a child with asthma. Smoking outside the house is not enough. Family members and visitors who smoke outside carry smoke residue inside on their clothes and hair -- this can trigger asthma symptoms.
Persons with asthma should also avoid air pollution, industrial dusts, and other irritating fumes, as much as possible.
National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Rockville, MD. National Heart, Lung, and Blood Institute, US Dept of Health and Human Services; 2007. NIH publication 08-4051.