Asthma By Mayo Clinic staff

Transcription

1 MayoClinic.com reprints This single copy is for your personal, noncommercial use only. For permission to reprint multiple copies or to order presentation-ready copies for distribution, use the reprints link below. Order reprints of this article now. Asthma By Mayo Clinic staff Original Article: Definition When you have asthma, your airways narrow and swell. They produce extra mucus, and breathing becomes difficult. The most common asthma signs and symptoms are coughing, wheezing and shortness of breath. For some people, asthma symptoms are a minor nuisance. For others, they're a major problem that interferes with daily activities. If you have severe asthma, you may be at risk of a life-threatening asthma attack. Asthma can't be cured, but its symptoms can be controlled. Treatments include taking steps to avoid your particular asthma triggers, using long-term control medications to prevent flare-ups and using a quick-relief inhaler to control symptoms once they start. Because asthma changes over time, you'll work with your doctor to track your signs and symptoms and adjust treatment as needed. Symptoms Asthma symptoms range from minor to severe and vary from person to person. You may have mild symptoms and asthma attacks may be infrequent. Between asthma flare-ups you may feel Asthma attack 1 of 16 12/1/11 8:51 AM

2 normal and have no trouble breathing. You may have symptoms primarily at night, during exercise or when you're exposed to specific triggers. Or you may have asthma symptoms all the time. Asthma signs and symptoms include: Shortness of breath Chest tightness or pain Trouble sleeping caused by shortness of breath, coughing or wheezing An audible whistling or wheezing sound when exhaling (wheezing is a common sign of asthma in children) Bouts of coughing or wheezing that are worsened by a respiratory virus such as a cold or the flu Signs that your asthma is probably getting worse include: More frequent and bothersome asthma signs and symptoms Increasing difficulty breathing (this can be measured by a peak flow meter, a simple device used to check how well your lungs are working) An increasingly frequent need to use a quick-relief inhaler For some people, asthma symptoms flare up in certain situations: Exercise-induced asthma occurs during exercise. For many people, exercise-induced asthma is worse when the air is cold and dry. Occupational asthma is asthma that's caused or worsened by breathing in a workplace irritant such as chemical fumes, gases or dust. Allergy-induced asthma. Some people have asthma symptoms that are triggered by particular allergens, such as pet dander, cockroaches or pollen. When to see a doctor These key circumstances may lead you to talk to your doctor about asthma: If you think you have asthma. If you have frequent coughing that lasts more than a few days or any other signs or symptoms of asthma, see your doctor. Treating asthma early, especially in children, may prevent long-term lung damage and help keep the condition from worsening over time. To monitor your asthma after diagnosis. If you know you have asthma, 2 of 16 12/1/11 8:51 AM

3 work with your doctor to keep it under control. Good long-term asthma control not only helps you feel better on a daily basis, but also can prevent a life-threatening asthma attack. If your asthma symptoms get worse. Contact your doctor right away if your medication doesn't seem to ease your symptoms or you need to use your quick-relief inhaler more and more often. Don't try to solve the problem by taking more medication without consulting your doctor. Overusing asthma medication can cause side effects and may even make your asthma worse. To review your treatment. Asthma changes over time. Meet with your doctor on a regular basis to discuss your symptoms and make any needed adjustments to your treatment. When to seek emergency treatment Severe asthma attacks can be life-threatening. Work with your doctor ahead of time to determine what to do when your signs and symptoms worsen and when you need emergency treatment. If your quick-relief medications don't relieve symptoms of a severe asthma attack, seek emergency help right away. Signs of an asthma emergency include: Causes Rapid worsening of shortness of breath or wheezing No improvement even after using a quick-relief inhaler such as albuterol Shortness of breath when you are doing minimal physical activity It isn't clear why some people get asthma and others don't, but it's probably due to a combination of environmental and genetic (inherited) factors. Asthma triggers are different from person to person. Exposure to a number of different allergens and irritants can trigger signs and symptoms of asthma, including: Airborne allergens, such as pollen, animal dander, mold, cockroaches and dust mites Respiratory infections, such as the common cold Physical activity (exercise-induced asthma) Cold air 3 of 16 12/1/11 8:51 AM

4 Air pollutants and irritants, such as smoke Certain medications, including beta blockers, aspirin and other nonsteroidal anti-inflammatory drugs Strong emotions and stress Sulfites, preservatives added to some types of foods and beverages Gastroesophageal reflux disease (GERD), a condition in which stomach acids back up into your throat Menstrual cycle in some women Allergic reactions to some foods, such as peanuts or shellfish Risk factors Asthma is common, affecting millions of adults and children. A growing number of people are diagnosed with the condition each year, but it isn't clear why. A number of factors are thought to increase your chances of developing asthma. These include: Having a blood relative (such as a parent or sibling) with asthma Having an allergic condition, such as atopic dermatitis or allergic rhinitis (hay fever) Being overweight Being a smoker Exposure to secondhand smoke Having a mother who smoked while pregnant Exposure to exhaust fumes or other types of pollution Exposure to occupational triggers, such as chemicals used in farming, hairdressing and manufacturing Low birth weight Exposure to allergens, exposure to certain germs, and having some types of bacterial or viral infections may also be risk factors. However, more research is needed to determine what role they may play in developing asthma. Complications 4 of 16 12/1/11 8:51 AM

5 react to the trigger, you likely have asthma. This test may be used if your initial lung function test is normal. Nitric oxide test. This test is sometimes used to diagnose and monitor asthma. It measures the amount of a gas called nitric oxide you have in your breath. If your airways are inflamed a sign of asthma you may have higher than normal nitric oxide levels. This test isn't widely available. How asthma is classified To classify your asthma severity, your doctor will consider your answers to questions about symptoms (such as how often you have asthma attacks and how bad they are), along with the results of your physical exam and diagnostic tests. Determining the severity level of your asthma will help your doctor choose the best treatment for you. Asthma severity often changes over time, requiring an adjustment to treatment. Asthma is classified into four general categories: Asthma classification Mild intermittent Mild persistent Moderate persistent Severe persistent Signs and symptoms Mild symptoms up to two days a week and up to two nights a month Symptoms more than twice a week, but no more than once in a single day Symptoms once a day and more than one night a week Symptoms throughout the day on most days and frequently at night Treatments and drugs Prevention and long-term control is the key to preventing asthma attacks. Treatment usually involves learning to recognize your triggers and taking steps to avoid them, and tracking your breathing to make sure your daily asthma medications are keeping symptoms under control. In case of an asthma flare-up, you may need to use a quick-relief inhaler such as albuterol. Medications The right medications for you depend on a number of things, including your age, your symptoms, your asthma triggers and what seems to work best to keep your asthma under control. Preventive, long-term control medications reduce the inflammation in your airways that leads to symptoms. Quick-relief inhalers (bronchodilators) quickly open swollen airways that are limiting breathing. In some cases, medications to treat specific allergies are needed. 8 of 16 12/1/11 8:51 AM

6 Long-term control medications In most cases, these medications need to be taken every day. Types of long-term control medications include: Inhaled corticosteroids. These medications include fluticasone (Flovent Diskus, Flovent HFA), budesonide (Pulmicort Flexhaler), mometasone (Asmanex), flunisolide (Aerobid), beclomethasone (Qvar) and others. They are the most commonly prescribed type of long-term asthma medication. You may need to use these medications for several days to weeks before they reach their maximum benefit. Unlike oral corticosteroids, these corticosteroid medications have a relatively low risk of side effects and are generally safe for long-term use. Leukotriene modifiers. These oral medications include montelukast (Singulair), zafirlukast (Accolate) and zileuton (Zyflo, Zyflo CR). They help prevent asthma symptoms for up to 24 hours. In rare cases, these medications have been linked to psychological reactions such as agitation, aggression, hallucinations, depression and suicidal thinking. Seek medical advice right away for any unusual reaction. Long-acting beta agonists (LABAs). These inhaled medications include salmeterol (Serevent Diskus) and formoterol (Foradil Aerolizer). LABAs open the airways and reduce inflammation. However, they've been linked to severe asthma attacks. LABAs should be taken only in combination with an inhaled corticosteroid. Combination inhalers such as fluticasone and salmeterol (Advair Diskus) and budesonide and formoterol (Symbicort). These medications contain a LABA along with a corticosteroid. Like other LABA medications, these medications may increase your risk of having a severe asthma attack. Theophylline. This is a daily pill that helps keep the airways open (bronchodilator). Theophylline (Theo-24, Elixophyllin, others) relaxes the muscles around the airways to make breathing easier. It's not used as often now as in past years. Quick-relief medications Quick-relief (rescue) medications are used as needed for rapid, short-term symptom relief during an asthma attack or before exercise if your doctor recommends it. Types of quick-relief medications include: 9 of 16 12/1/11 8:51 AM

7 Asthma - PubMed Health Asthmatic bronchiole and normal bronchiole Asthma is a disease in which inflammation of the airways causes airflow into and out of the lungs to be restricted. When an asthma attack occurs, mucus production is increased, muscles of the bronchial tree become tight, and the lining of the air passages swells, reducing airflow and producing the characteristic wheezing sound. Review Date: 5/1/2011. Reviewed by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. A.D.A.M., Disclaimer Copyright 2011, A.D.A.M., Inc. PubMed Health. A service of the National Library of Medicine, National Institutes of Health. 1 of 1 12/1/11 8:42 AM

8 Exercise Induced Asthma: Exercise can even induce an asthma attack in people who have no other triggers and do not experience asthma under any other circumstances. People with exercise-induced asthma are believed to be more sensitive to changes in the temperature and humidity of the air. When you are at rest, you breathe through your nose, which serves to warm, humidify, and cleanse the air you inhale to make it more like the air in the lungs. When you are exercising, you breathe through your mouth, and the air that hits your lungs is colder and drier. The contrast between the warm air in the lungs and the cold inhaled air or the dry inhaled air and moist air in the lungs, can trigger an attack. Once the attack is triggered, the airways begin to swell (bronchospasm) and secrete large amounts of mucus. The swelling and extra mucus partially block or obstruct the airways. This makes it more difficult to push air out of your lungs (exhale).