Asthma

Definition

Asthma is inflammation and narrowing of the bronchial tubes. Air travels in and out of the lungs through these tubes.

Inflamed Bronchus in the Lungs

© 2008 Nucleus Medical Art, Inc.

Causes

The cause of asthma is not known. It does seem to run in some families. Current research suggests a combination of environment, genetics and biology may lead to asthma. Possible triggers of an asthma attack in a person with asthma include:

  • Exercise
  • Cold weather
  • 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 or air pollution
    • 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
  • Gastroesophageal reflux disease (GERD)

Symptoms

Symptoms include:

  • Wheezing
  • Tightness in the chest
  • Trouble breathing
  • Shortness of breath
  • Cough
  • Chest pain
  • Self-limited exercise, difficulty keeping up with peers

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
  • Bronchoprovocation tests—lung function tests performed after exposure to methacholine, histamine, or cold or dry air, to stimulate asthma
    • Can help to confirm asthma in unclear cases, but not often used in a general practice setting
  • Exhaled nitric oxide (a marker of airway inflammation)—to confirm the diagnosis and manage medications
  • Allergy tests—usually skin or sometimes blood tests to find out if allergies are causing your symptoms

Treatment

The treatment approach to asthma is four-fold:

Often, you'll need to take more than one type of medication.

Asthma Medications

  • Quick-acting beta agonists—(eg, inhaled albuterol or xopenex) relax your airways so that they become wider again
    • Also called rescue inhalers, are used to stop an acute episode of asthma, or "asthma attack"
  • Long-acting beta agonists—(eg, inhaled salmeterol) used daily to prevent asthma attacks
    • Should not be used to try to stop an asthma attack in progress
    • A study showed that long-acting inhalers, like salmeterol, may increase the risk of a life-threatening asthma attack and asthma-related death if taken for more than three months, talk to your doctor about risks *
  • Inhaled steroid—used daily to reduce inflammation in your airways, 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
    • May also be used just before exercise for exercise induced asthma
    • Should not be used to try to stop an asthma attack in progress
  • Zafirlukast, Zileuton, and Montelukast—taken daily to help prevent asthma attacks
  • Omalizumab (Xolair)—a monoclonal antibody against immunoglobulin E (IgE), used in conjunction with other medications
    • Given as a subcutaneous injection to treat allergic asthma
  • Anticholinergic agents— inhaled medications, such as ipratropium, that function as a bronchodilator
  • Corticosteroids—pills, injections, or intravenous (IV) medications given to treat acute flare-up of symptoms
    • Corticosteroid pills may be taken for a longer period of time if you have severe asthma that isn't responding to other treatments
  • Theophylline—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 things that trigger the attacks. Some general guidelines include:

  • 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 days with high air pollution, a high pollen count, or a high ozone level.
  • Get a yearly flu shot.
  • Treat allergies and sinusitis.
  • Don't smoke.
  • Avoid breathing in chemicals or second-hand smoke.
  • 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.

RESOURCES:

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

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

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

CANADIAN RESOURCES:

Allergy Asthma Information Association
http://aaia.ca/

The Canadian Lung Association
http://www.lung.ca/

References:

Bone R, et al. Pulmonary and Critical Care Medicine. St. Louis, MO: Mosby-Year Book, Inc;1998.

Cecil RL, Goldman L, Bennett JC. Cecil Textbook of Medicine. 21st ed. Philadelphia, PA: WB Saunders Company;2000.

Conn HF, Rakel RE. Conn's Current Therapy 2001. 53rd ed. Philadelphia, PA: WB Saunders Company;2001.

High ozone levels harmful to respiratory system, especially for asthmatics. American Academy of Allergy, Asthma & Immunology website. Available at http://www.aaaai.org/media/resources/academy_statements/position_statements/mold.pdf. Accessed June 23, 2008.

Kleigman RM, Jensen HB, Behrman RE, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Saunders Elsevier;2007.

*Updated section on Treatment on 9/14/06 according to the following study, as cited by DynaMed's Systematic Literature Surveillance: Salpeter SR, Buckley NS, Ormiston TM, et al. Meta-analysis: effect of long-acting beta-agonists on severe asthma exacerbations and asthma-related deaths. Ann Intern Med. 2006;144:904-912.



Last reviewed November 2007 by Kari Kassir, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.


Your Health and Happiness


DiggDeliciousNewsvineRedditStumbleTechnoratiFacebook