Overview, Causes, & Risk Factors

Asthma is a common lung disease that causes repeated bouts ofwheezing, shortness of breath, chest tightness, and coughing, especially atnight or in the early morning. A person with asthma has difficulty breathingbecause of inflammation and narrowing of the airways.

What is going on in the body?

In a person with asthma, the airways narrow as a result of irritation and inflammation.During an asthma flare-up or “asthma attack,” muscles of the airwaytubes, or bronchi, tighten. The reaction in the lungs is out of proportion withthe amount of stimulation experienced. The inflammation and tightening in theairways increases, trapping air in the lungs. The overreaction to the triggercauses excess mucus to form in the lungs. The person cannot take in a fullbreath and feels short of breath.

Sometimes the reaction to the trigger causes swelling throughout the entirebronchial tube. The opening in the center of the tube then becomes smaller, andbreathing becomes more difficult. When the muscles relax, the bronchial tubesopen wider. Asthma symptoms then resolve, and breathingbecomes easier.

What are the causes and risks of the disease?

Asthma is caused by an immune system response. The immune system overreacts totriggers and causes the airways to become inflamed and tight. Often there areprovoking factors, or triggers, that cause asthmasymptoms. Triggers differ from person to person. Asthma triggers include:

  • allergies to food such as peanutsor to foods with sulfites, such as beer, wine, processed foods, and shrimp
  • cold and dry air and wind
  • dust and dust mites
  • exercise
  • heartburn
  • hormonal changes resulting from pregnancyor menstruation
  • indoor and outdoor pollution from exposure to fumes, paint, fireplacesmoke, or perfume
  • medicine allergies
  • mold
  • pets with fur or feathers
  • pollen
  • smoke inhalation
  • stress
  • viral infections, such as a cold or flu
  • Symptoms & Signs

    What are the signs and symptoms of the disease?

    Following are the main symptoms of asthma:

  • coughing
  • production of excess mucus
  • shortness of breath
  • tightness in the chest
  • wheezing
  • Some people have all of these asthma symptoms. Others have just a few or onlyone. Symptoms often get worse in the early morning and during the night.

    Diagnosis & Tests

    How is the disease diagnosed?

    Diagnosis of asthma begins with a medical history and physicalexam. Pulmonary function tests are simple breathing teststhat are often used to measure breathing limitations.Sometimes chest X-rays can show air trapped in the lungs.

    Sometimes a person has symptoms of asthma, but showsnormal results on pulmonary function tests. In this case, the healthcareprovider may order a bronchoprovocation test. This type of test increases thedemand on the lungs and may provoke symptoms of asthma. A medicine such asmethacholine may be given to the individual to provoke symptoms. Alternately,the person may be asked to walk on a treadmill or do some other form ofexercise. When the lungs are working their hardest, pulmonary function tests may then be able to detectairway problems.

    Prevention & Expectations

    What can be done to prevent the disease?

    There are no immunizations or other treatments that can prevent asthma, but some measures can help to prevent flare-ups of asthma. Once anindividual has been diagnosed with asthma, the healthcare provider will recommend atreatment plan. The plan usually includes identifying and avoiding any triggers andtaking medicines. By following the treatment plan, an individual can minimizeasthma flare-ups.

    What are the long-term effects of the disease?

    Asthma is characterized by periodic flare-ups. Between flare-ups, many people will have a return to normal breathing. Over many years, this pattern can continue without theperson getting dramatically worse. In some people, asthma flare-ups increase asthey get older.

    In people with more severe asthma, long-terminflammation can lead to permanent changes in the airways. This is calledairway remodeling. The actual structure of the airway walls can change, causingblockage that can’t be completely reversed with treatment.

    Some children outgrow asthma. Sometimes symptoms stop and asthma disappears asthey grow up.

    What are the risks to others?

    Asthma is not contagious and poses no risk to others.

    Treatment & Monitoring

    What are the treatments for the disease?

    Successful treatment of asthma involves two important factors:

  • avoiding known irritants or triggers
  • taking medicines to reduce airway inflammation
  • Avoiding known irritants is key to controlling asthma. Avoid anything that onecan see or smell in the air, especially cigarette smoke, dust, and strongchemical odors. Many people with asthma also have allergies. Allergic reactionscan trigger an asthma flare-up. Avoiding things that cause the allergies,called allergens, is important. Controlling allergies with appropriate medicine or allergy shots can often improveasthma symptoms.

    Medicines for treatment of asthma include both quick-relief andlong-term-control medicines. The healthcare provider will prescribe theappropriate medicines for each individual. In general, the following principlesare used:

  • people who have asthma only intermittently are given quick-reliefmedicines
  • people with persistent asthma are often given both quick-relief andlong-term-control medicines
  • people with exercise-induced asthma symptoms may be told to takequick-relief or long-term-control medicines right before exercise
  • Quick-relief medicines work within minutes. They prevent or help reduce thetightening of the muscles of the bronchial tubes. They are used when aperson experiences an asthma attack or sudden shortness of breath. Short-actingbeta-2 agonists, such as albuterol, are used for quick symptom relief. These medicines are usuallytaken through a metered dose inhaler or nebulizer.

    Long-term-control medicines are taken on a regular basis to calmthe airways and prevent symptoms. They are not effective for quickrelief during an asthma attack. These medicines include:

  • cromolyn and nedocromil, which act on the immune system to reduceinflammation
  • inhaled or oral corticosteroids, which prevent swelling and irritation ofthe airways
  • leukotriene modifiers, which block the chemicals that start airwayinflammation
  • long-acting inhaled beta-2 agonists, which help relax the airways
  • methylxanthines, which relax the airway muscles
  • What are the side effects of the treatments?

    Short-acting beta-2 agonists and anticholinergics may cause thefollowing side effects:

  • cough
  • dizziness
  • dry mouth and difficulty speaking
  • headache
  • high blood pressure
  • nausea
  • racing heartbeat
  • Corticosteroids have fewer side effects when given by inhaler than when theyare taken orally. Side effects may include:

  • bone thinning
  • change in voice tone
  • growth problems in children
  • headache
  • muscle weakness
  • oral thrush, a yeastinfection in the mouth
  • weight gain
  • Long-acting beta-2 agonists may cause the following side effects:

  • difficulty sleeping
  • dizziness
  • dry mouth
  • feeling nervous or shaky
  • headache
  • Leukotriene modifiers may cause:

  • abdominal pain anddiarrhea
  • fatigue
  • nausea andvomiting
  • sore throat
  • Methylxanthines may cause:

  • difficulty sleeping
  • headache
  • irritability andshakiness
  • nausea andvomiting
  • palpitations
  • Cromolyn and nedocromil may cause:

  • a bad taste in the mouth
  • chest tightness
  • cough
  • headache
  • nausea
  • sneezing
  • What happens after treatment for the disease?

    Effective treatment of asthma reduces inflammation and tightening of theairways, lowering the frequency of asthma attacks. Successful treatment allowspeople with asthma to enjoy life without significant breathing problems.

    How is the disease monitored?

    A person with asthma can monitor breathing at home with a devicecalled apeak flow meter. Some people use peak flow meters every day and keep a record intheir asthma diary. Airway changes show up on a peak flow meterbefore symptoms are even felt. Following the treatment plan at this time will often prevent an asthma attack from getting any worse.

    Periodic pulmonary function testing can help guide the healthcareprovider in prescribing medicines. Any new or worsening symptoms should bereported to the healthcare provider.

    Article type: xmedgeneral