Asthma

Lungs — The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.

Also known as: Bronchial asthma and Exercise-induced asthma

Definition

Asthma is an inflammatory disorder of the airways, which causes attacks of wheezing, shortness of breath, chest tightness, and coughing.

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 swells. This reduces the amount of air that can pass by.

In sensitive people, asthma symptoms can be triggered by breathing in allergy-causing substances (called allergens or triggers).

Common asthma triggers include:

Animals (pet hair or dander)
Dust
Changes in weather (most often cold weather)
Chemicals in the air or in food
Exercise
Mold
Pollen
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 a personal or family history of allergies, such as hay fever (allergic rhinitis) or eczema. Others have no history of allergies.

Symptoms

Most people with asthma have attacks separated by symptom-free periods. Some people have long-term shortness of breath with episodes of increased shortness of breath. Either wheezing or a cough may be the main symptom.

Asthma attacks can last for minutes to days, and can become dangerous if the airflow is severely restricted.

Symptoms include:

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
Wheezing, which:
- Comes in episodes with symptom-free periods in between
- 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

Emergency symptoms:

Bluish color to the lips and face
Decreased level of alertness, such as severe drowsiness or confusion, during an asthma attack
Extreme difficulty breathing
Rapid pulse
Severe anxiety due to shortness of breath
Sweating

Other symptoms that may occur 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 to identify allergens in people with persistent asthma. Common allergens include:

Cockroach allergens
Dust mites
Molds
Pet dander
Pollens

Common respiratory irritants include:

Fumes from burning wood or gas
Pollution
Tobacco smoke

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

Treatment

The goal of treatment is to avoid the substances that trigger your symptoms and 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 treating asthma:

Control drugs to prevent attacks
Quick-relief drugs for use during attacks

Control drugs for asthma control your symptoms if you don't have mild asthma. You must take them every day for them to work. Take them even when you feel okay.

The most common control drugs are:

Inhaled corticosteroids (such as Azmacort, Vanceril, AeroBid, Flovent) prevent symptoms by helping to keep your airways from swelling up.
Long-acting beta-agonist inhalers also help prevent asthma symptoms. Do not take long-acting beta-agonist inhaler drugs alone. These drugs are generally used together with an inhaled steroid drug. It may be easier to use an inhaler that contains both drugs.

Other control drugs that may be used are:

Leukotriene inhibitors (such as Singulair and Accolate)
Omalizumab (Xolair), which blocks a pathway that the immune system uses to trigger asthma symptoms
Cromolyn sodium (Intal) or nedocromil sodium (Tilade)
Aminophylline or theophylline (rarely used anymore)

Asthma quick-relief drugs work fast to control asthma symptoms:

You take them when you are coughing, wheezing, having trouble breathing, or having an asthma attack. They are also called "rescue" drugs.
They also can be used just before exercising to help prevent asthma symptoms that are caused by exercise.
Tell your doctor if you are using quick-relief medicines twice a week or more to control your asthma symptoms. Your asthma may not be under control, and your doctor may need to change your dose of daily control drugs.

Quick-relief drugs include:

Short-acting bronchodilators (inhalers), such as Proventil, Ventolin, and Xopenex
Your doctor might prescribe oral steroids (corticosteroids) when you have an asthma attack that is not going away. These are medicines that you take by mouth as pills, capsules, or liquid. Plan ahead. Make sure you do not run out of these medications.

A severe asthma attack requires a check-up by a doctor. You may also need a hospital stay, oxygen, and medications given through a vein (IV).

Asthma action plans are written documents for anyone with asthma. An asthma action plan should include:

A plan for taking asthma medications when your condition is stable
A list of asthma triggers and how to avoid them
How to recognize when your asthma is getting worse, and when to call your doctor or nurse

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.

Support Groups

You can often ease the stress caused by illness by joining a support group, where members share common experiences and problems.

See: Asthma and allergy - support group

Expectations (prognosis)

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.

Complications

The complications of asthma can be severe. Some include:

Death
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:

You develop drowsiness or confusion
You have severe shortness of breath at rest
Your peak flow measurement is less than 50% of your personal best
You have severe chest pain

Prevention

You can reduce asthma symptoms by avoiding known triggers and substances that irritate the airways.

Cover bedding with "allergy-proof" casings to reduce exposure to dust mites.
Remove carpets from bedrooms and vacuum regularly.
Use only unscented detergents and cleaning materials in the home.
Keep humidity levels low and fix leaks to reduce the 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 bedroom. Place filtering material over the heating outlets to trap animal dander.
Eliminate tobacco smoke from the home. This 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.

References

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.

Wechsler ME. Managing asthma in primary care: putting new guideline recommendations into context. Mayo Clin Proc. 2009;84:707-717.

Fanta CH. Asthma. N Engl J Med. 2009;360:1002-1014.

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Review date:: July 14, 2010
Reviewed by:: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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