Asthma

Definition

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

Alternative Names

Causes

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. Still, 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). Triggers include pet dander, dust mites, cockroach allergens, molds, or pollens. Asthma symptoms can also be triggered by respiratory infections, exercise, cold air, tobacco smoke and other pollutants, stress, food, or drug allergies. Aspirin and other non-steroidal anti-inflammatory medications (NSAIDS) provoke asthma in some patients.

Approximately 20.5 million Americans currently have asthma. Many people with asthma have an individual or family history of allergies, such as hay fever (allergic rhinitis) or eczema

Symptoms

• Wheezing
  • Usually begins suddenly
  • Comes in episodes
  • May be worse at night or in early morning
  • Gets worse with cold aira, exercise, and heartburn (reflux)
  • May go away on its own
  • Is relieved by bronchodilators (drugs that open the airways)
• Cough with or without sputum (phlegm) production
• Shortness of breath that gets worse with exercise or activity
• Intercostal retractions (pulling of the skin between the ribs when breathing)

Emergency symptoms:

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

Additional symptoms that may be associated with this disease:

• Nasal flaring
• Chest pain
• Tightness in the chest
• Abnormal breathing pattern --breathing out takes more than twice as long as breathing in
• Breathing temporarily stops

Exams and Tests

Allergy testing may be helpful in identifying allergens in patients 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:

• Lung function tests
• Peak flow measurements
• Chest x-ray
• Blood tests, including eosinophil count (a type of white blood cell)
• Arterial blood gas

Treatment

Treatment is aimed at avoiding known allergens and respiratory irritants and controlling symptoms and airway inflammation through medication.

There are two basic kinds of medication for the treatment of asthma:

Long-term control medications are used on a regular basis to prevent attacks, not for treatment during an attack. Types include:

• Inhaled steroids (such as Azmacort, Vanceril, AeroBid, Flovent) prevent inflammation
• Leukotriene inhibitors (such as Singulair and Accolate)
• Anti-IgE therapy (Xolair), a medicine given by injection to patients with more severe asthma
• Long-acting bronchodilators (such as Serevent) help open airways
• Cromolyn sodium (Intal) or nedocromil sodium
• Aminophylline or theophylline (not used as frequently as in the past)

Sometimes a combination of steroids and bronchodilators are used, using either separate inhalers or a single inhaler (such as Advair Diskus).

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 prednisone or methylprednisolone) given by mouth or into a vein

Persons 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 medical evaluation and may require a hospital stay, oxygen, and intravenous medications.

A peak flow meter, a simple device to measure lung volume, can be used at home to help you "see an attack coming" and take the appropriate action, sometimes even before any symptoms appear. If you are not monitoring asthma on a regular basis, an attack can take you by surprise.

Peak flow measurements can help show when medication is needed, or other action needs to be taken. Peak flow values of 50-80% of an individual's personal best results indicate a moderate asthma attack, while values below 50% indicate a severe attack.

Support Groups

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.

Outlook (Prognosis)

There is no cure for asthma, though symptoms sometimes decrease over time. With proper self management and medical treatment, most people with asthma can lead normal lives.

Possible Complications

• Respiratory fatigue
• Side effects of asthma medications
• Pneumothorax
• Death

When to Contact a Medical Professional

Call for an appointment with your health care provider if you or your child experience mild asthma symptoms (to discuss treatment options).

Call your health care provider (or go to the emergency room) for moderate shortness of breath (shortness of breath with talking, peak flow 50-80% of personal best), if symptoms worsen or do not improve with treatment, or an attack requires more medication than recommended in the prescription.

Go to the emergency room for severe shortness of breath (shortness of breath at rest, peak flow less than 50% of personal best), if drowsiness or confusion develops, or for severe chest pain.

Prevention

Asthma symptoms can be substantially reduced by avoiding known allergens and respiratory irritants. If someone with asthma is sensitive to dust mites, exposure can be reduced by encasing mattresses and pillows in allergen-impermeable covers, removing carpets from bedrooms, and by vacuuming regularly. Exposure to dust mites and mold can be reduced by lowering indoor humidity.

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. Exposure to cigarette smoke, air pollution, industrial dusts, and irritating fumes should also be avoided.

Allergy desensitization may be helpful in reducing asthma symptoms and medication use, but the size of the benefit compared with other treatments is not known.

Guidelines for the Diagnosis and Management of Asthma -- Update on Selected Topics 2002. Bethesda, MD. 2003 June. National Asthma Education and Prevention Program. NIH publications 02-5074.