Asthma

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Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention | Organizations

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Definition

Asthma is inflammation and narrowing of the airways (called the bronchial tubes).

Causes

The cause of asthma is not known. It does seem to run in some families. If a person has asthma, the following things can trigger an attack:

• Exercise
• Cold
• Viral illness
• Sinusitis
• Gastroesophageal reflux disease (GERD)
• Sulfites used in dried fruits and wine
• Medications, such as aspirin, ibuprofen, and beta-blockers
• Exposure to irritants or allergens, including:
  • Cigarette smoke, smoke from a wood-burning stove
  • Pet dander
  • Dust
  • Chemicals
  • Mold and mildew
  • Pollen
  • Smog
  • Perfumed products

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

• Living in a large urban area
• Regularly breathing in cigarette smoke (including second-hand smoke)
• Regularly breathing in industrial or agricultural chemicals
• A parent who has asthma
• History of multiple respiratory infections during childhood
• Low birth weight
• Being overweight
• GERD

Symptoms

Symptoms include:

• Wheezing
• Tightness in the chest
• Trouble breathing
• Shortness of breath
• Cough
• Chest pain

Diagnosis

The doctor will ask about your symptoms and medical history and perform a physical exam:

Tests may include:

Peak Flow Examination – blowing quickly and forcefully into a special instrument that measures your output of air

Pulmonary Function Tests (PFTs) – breathing into a machine that records information about the function of your lungs

Methacholine Provocation Test – lung function tests performed after taking a small dose of methacholine, which causes narrowing of the airways in susceptible people

Allergy Tests – tests to find out if allergies are causing your symptoms

Treatment

Asthma is treated with medication. Often, you'll need to take more than one type of medication.

Asthma medications include:

Quick-Acting Inhaler (such as albuterol) – relaxes your airways so that they become wider again. These are used to stop an acute episode of asthma, or "asthma attack." (also called a rescue inhaler)

Long-Acting Inhaler (such as salmeterol) – used daily to prevent asthma attacks. This inhaler should not be used to try to stop an asthma attack in progress.

Steroid Inhaler – used to reduce inflammation in your airways. This inhaler should not be used to try to stop an asthma attack in progress.

Cromolyn Sodium or Nedocromil Sodium Inhaler – used daily to prevent asthma flare-ups. These may also be used just before exercise, if you have exercise-induced asthma. This inhaler should not be used to try to stop an asthma attack in progress.

Zafirlukast and Zileuton – pills taken daily to help prevent asthma attacks

Corticosteroids – pills, injections, or intravenous (IV) medications given to treat an acute flare-up of symptoms. You may also take corticosteroid pills if you have severe asthma that isn't responding to other treatments.

Theophylline – pills taken daily to help prevent asthma attacks

Epinephrine – a shot given to stop an asthma attack

Prevention

There are no guidelines for preventing asthma because the cause is not known. However, you can help prevent asthma attacks by avoiding substances that trigger asthma attacks.

• Keep windows closed.
• Consider getting HEPA filters for your heating/cooling system and your vacuum cleaner.
• Keep the humidity down in your house.
• Avoid strenuous outdoor exercise during high-ozone days.
• Get a yearly flu shot.
• Don't smoke.
• Avoid breathing in second-hand smoke and chemicals.
• Don't use a wood-burning stove regularly.
• Consider getting allergy shots, if allergies trigger your asthma attacks.
• Talk to your doctor about an appropriate level of exercise for you.
• Talk to your doctor about how to track your asthma, so you can identify and treat flare-ups immediately.

Organizations

American Lung Association
http://www.lungusa.org/

Asthma and Allergy Foundation of America
http://www.aafa.org/

American Academy of Allergy, Asthma and Immunology
http://www.aaaai.org/

SOURCES:

Pulmonary & Critical Care Medicine. Mosby-Year Book, Inc., 1998.

Cecil Textbook of Medicine, 21st ed. W. B. Saunders Company, 2000.

Conn's Current Therapy 2001, 53rd ed. W. B. Saunders Company, 2001.

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Last reviewed June 2001 by Medical Review Board