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Asthma

Asthma

Definition

Asthma is a chronic (long-lasting) inflammatory disease of the airways. In people susceptible to asthma, this inflammation causes the airways to narrow periodically. This narrowing, in turn, produces wheezing and breathlessness that sometimes causes the patient to gasp for air. Obstruction to air flow either stops spontaneously or responds to a wide range of treatments, but continuing inflammation makes the airways hyper-responsive to stimuli such as cold air, exercise , dust mites, pollutants in the air, and even stress and anxiety .

Description

The changes that take place in the lungs of people with asthma make the airways (the "breathing tubes," or bronchi and the smaller bronchioles) hyper-reactive to many different types of stimuli that do not affect healthy lungs. In an asthma attack, the muscle tissues in the walls of the bronchi go into spasm, and the cells lining the airways swell and secrete mucus into the air spaces. These two actions cause the bronchi to become narrowed (bronchoconstriction). As a result, a person with asthma has to make a much greater effort to breathe.

Cells in the bronchial walls, called mast cells, release certain substances that cause the bronchial muscles to contract and stimulate mucus formation. These substances, including histamine and a group of chemicals called leukotrienes, also bring white blood cells into the area, which play a key role in the inflammatory response. Many patients with asthma are prone to react to such "foreign" substances as pollen, house dust mites, or animal dander. These are called allergens. An acute asthma attack can begin immediately after exposure to a trigger or several days or weeks later.

When asthma begins in childhood, it often affects a child who is likely, for genetic reasons, to become sensitized to common "allergens" in the environment (atopic person). When these children are exposed to house dust mites, animal proteins, fungi, or other potential allergens, they produce a type of antibody that is intended to engulf and destroy the foreign materials. This makes the airway cells sensitive to particular materials. Further exposure can rapidly lead to an asthmatic response.

Demographics

Asthma affects about 17 million Americans, including nearly five million children. Asthma usually begins in childhood or adolescence , but it also may first appear in adulthood. Asthma is the leading cause of chronic illness in children, accounting for 14 million missed school days annually. It is the third-ranking cause of hospitalization among children under age 15.

Asthma affects as many as 1012 percent of children in the United States and the number has been steadily increasing. Since 1980, asthma has increased by 160 percent among children at least four years of age. Asthma is becoming more frequent, anddespite modern drug treatmentsit is more severe than in the past. Some experts suggest this is due to increased exposure to allergens such as dust, air pollution, second-hand smoke, and industrial components.

Asthma can begin at any age, but most children experience their first symptoms by the time they are five years old. Boys have a higher incidence of asthma than girls, and the disease is more prevalent in African American children. Children living in inner cities, low-income populations, and minorities have disproportionately higher morbidity and mortality due to asthma.

Causes and symptoms

Causes

About 80 percent of childhood asthma cases are caused by allergies . In most cases, inhaling an allergen sets off the chain of biochemical and tissue changes leading to airway inflammation, bronchoconstriction, and wheezing characteristic of asthma. Because avoiding (or at least minimizing) exposure is the most effective way of treating asthma, it is vital to identify the allergen or irritant that is causing symptoms in a particular child.

Once asthma is present, symptoms can be triggered or made worse if the child also has rhinitis (inflammation of the lining of the nose) or sinusitis. Gastroesophageal reflux disease (GERD), a condition that causes stomach acid to pass back up the esophagus, can worsen asthma. Many pulmonary infections in early childhood, including those due to Chlamydia pneumoniae, Mycoplasma pneumoniae, and respiratory syncytial virus, have been linked with an increased risk for wheezing and asthma. Aspirin and a class of drugs called beta-blockers (often used to treat high blood pressure) can also worsen the symptoms of asthma. Foggy and cloudy environments have been noted to aggravate asthma, and obesity facilitates asthma, but does not cause it.

The most important inhaled allergens and triggers contributing to attacks of asthma are:

  • animal dander
  • smites in house dust
  • fungi (molds) that grow indoors
  • mold spores that grow outdoors
  • cockroach allergens
  • tree, grass, and weed pollen
  • occupational exposure to chemicals, fumes, or particles of industrial materials in the air
  • strong odors, such as from perfume
  • wood smoke

Inhaling tobacco smoke (from secondhand smoke or smoking ) can irritate the airways and trigger an asthmatic attack. Air pollutants can have a similar effect.

There are three important factors that regularly produce attacks in certain patients with asthma, and they may sometimes be the sole cause of symptoms. They are:

  • humidity and temperature changes, especially inhaling cold air
  • exercise (in certain children, asthma is caused simply by exercising, and is called exercise-induced asthma)
  • stress, strong emotions, or a high level of anxiety

Risk factors

There are many risk factors for childhood asthma, including:

  • presence of allergies
  • family history of asthma and/or allergies
  • frequent respiratory infections
  • low birth weight
  • mother's exposure to tobacco smoke during pregnancy and/or child's exposure after birth
  • wheezing with upper respiratory infections

Symptoms

Wheezing is often very obvious, but mild asthmatic attacks may be confirmed when the physician listens to the patient's chest with a stethoscope. Wheezing is often loudest when the child breathes out, in an attempt to expel used air through the narrowed airways. Besides wheezing and shortness of breath, the child may cough and experience pain or pressure in the chest. The child may have itching on the back or neck at the start of an attack. Infants may have feeding problems and may grunt while sucking or feeding. Tiring easily or becoming irritated are other common symptoms.

Some children with asthma are free of symptoms most of the time, but may occasionally experience brief periods during which they are short of breath. Others spend much of their days (and nights) coughing and wheezing, until the asthma is properly treated. Crying or even laughing may bring on an attack. Severe episodes, which are less common, may be seen when the patient has a viral respiratory tract infection or is exposed to a heavy load of an allergen or irritant. Asthmatic attacks may last only a few minutes or can go on for hours or even days (a condition called status asthmaticus).

Asthma symptoms can be classified as:

  • Mild intermittent: Symptoms occur twice a week or less; nighttime symptoms occur twice a month or less; symptoms are brief and last a few hours to a few days; no symptoms occur between more severe episodes.
  • Mild persistent: Symptoms occur more than twice a week but not every day; nighttime symptoms occur more than twice a month; episodes are severe and sometimes affect activity.
  • Moderate persistent: Symptoms occur daily; nighttime symptoms occur more than once a week; quick-relief medication is used daily; symptoms affect daily activities; severe episodes occur twice a week or more and last for days.
  • Severe persistent: Symptoms occur continually throughout the day and frequently at night; symptoms affect daily activities and cause the patient to limit activities.

Shortness of breath may cause a patient to become very anxious, sit upright, lean forward, and use the neck or chest wall muscles to help with breathing. These symptoms require emergency attention. In a severe attack that lasts for some time, some of the air sacs in the lung may rupture so that air collects within the chest. This makes it even harder to breathe in adequate amounts of air.

Almost always, even patients with the most severe attacks will recover completely.

When to call the doctor

If a child has the following symptoms, the parent should contact the child's pediatrician:

  • inability to participate in normal activities
  • missed school due to asthma symptoms
  • symptoms that do not improve about 15 minutes after initial treatment with medication
  • signs of infection such as increased fatigue or weakness, fever or chills, sore throat , coughing up mucus, yellow or green mucus, sinus drainage, nasal congestion, headaches, or tenderness along the cheekbones

If the parent is unsure about what action to take to treat the child's symptoms, he or she should call the child's doctor.

The parent or caregiver should seek emergency care by calling 911 in most areas when the child has these symptoms or conditions:

  • bluish skin tone
  • bluish coloration around the lips, fingernail beds, and tongue
  • severe wheezing
  • uncontrolled coughing
  • very rapid breathing
  • inability to catch his or her breath
  • tightened neck and chest muscles due to breathing difficulty
  • inability to perform a peak expiratory flow
  • feelings of anxiety or panic
  • pale, sweaty face
  • difficulty talking
  • difficulty walking
  • confusion
  • dizziness or fainting
  • chest pain or pressure

Diagnosis

Early diagnosis is critical to proper asthma treatment and management. Asthma may be diagnosed by the child's primary pediatrician or an asthma specialist, such as an allergist.

The diagnosis of asthma may be strongly suggested when the typical symptoms and signs are present, including coughing, wheezing, shortness of breath, rapid breathing, or chest tightness. The physician will question the child (if old enough to provide an accurate history of symptoms) or parent about his or her physical health (the medical history), perform a physical examination, and perform or order certain tests to rule out other conditions.

The medical and family history help the physician determine if the child has any conditions or disorders that might be the cause of asthma. A family history of asthma or allergies can be a valuable indicator of asthma and may suggest a genetic predisposition to the condition. The physician will ask detailed questions about the child's symptoms, including when they first occurred, what seems to cause them, the frequency and severity, and how they are being managed.

During the physical exam, the pediatrician will listen to the patient's chest with a stethoscope to evaluate distinctive breathing sounds. He or she also will look for maximum chest expansion during inhalation. Hunched shoulders and contracting neck muscles are signs of narrowed airways. Nasal polyps or increased amounts of nasal secretions are often noted in patients with asthma. Skin changes, like atopic dermatitis or eczema, may demonstrate that the patient has allergic problems.

When asthma is suspected, the diagnosis can be confirmed using certain respiratory tests. Spirometry is a test that measures how rapidly air is exhaled and how much air is retained in the lungs. Usually the child should be at least five years of age for this test to be successful. During the test, the child exhales and the spirometer measures the airflow, comparing lung capacity to the normal range for the child's age and race. The child then inhales a drug that widens the air passages (a short-acting bronchodilator) and the doctor takes another measurement of the lung capacity. An increase in lung capacity after taking this medication often indicates the asthma symptoms are reversible (a very typical finding in asthma). The spirometer is similar to the peak flow meter that patients use to keep track of asthma severity at home.

Often, it is difficult to determine what is triggering asthma attacks. Allergy skin testing may be performed, especially if the doctor suspects the child's symptoms are persistent. An allergic skin response does not always mean that the allergen being tested is causing the asthma. Also, the body's immune system produces an antibody to fight off the allergen. The amount of antibody can be measured by a blood test that will show how sensitive the patient is to a particular allergen. If the diagnosis is still in doubt, the patient can inhale a suspect allergen while using a spirometer to detect airway narrowing. Spirometry can also be repeated after a bout of exercise if exercise-induced asthma is a possibility. A chest x ray will help rule out other disorders.

Treatment

Once asthma is diagnosed, a treatment plan should be initiated as quickly as possible to manage asthma symptoms.

In most cases, asthma treatment is managed by the child's pediatrician. Referral to an asthma specialist should be considered if:

  • There has been a life-threatening asthma attack or severe, persistent asthma.
  • Treatment for three to six months has not met its goals.
  • Some other condition, such as nasal polyps or chronic lung disease, complicates the asthma.
  • Special tests, such as allergy skin testing or an allergen challenge, are needed.
  • Intensive steroid therapy has been necessary.

The first step in bringing asthma under control is to reduce or avoid exposure to known allergens or triggers as much as possible. Treatment goals for all patients with asthma are to prevent troublesome symptoms, maintain lung function as close to normal as possible, avoid emergency room visits or hospitalizations, allow participation in normal activitiesincluding exercise and those requiring exertionand improve the quality of life.

Medications

The best drug treatment plan will control asthmatic symptoms while causing few or no side effects. The child's doctor will work with the parent to determine the drugs that are most appropriate and may be the most effective, based on the severity of symptoms. Age and the presence of other medical conditions may affect the drugs selected.

Two types of asthma medications include short-acting, quick relief, medications and long-acting, controller, medications. Quick relief medications are used to treat asthma symptoms when they occur. They relieve symptoms rapidly and are usually taken only when needed. Long-acting medications are preventative and are taken daily to help a patient achieve and maintain control of asthma symptoms.

Asthma treatment guidelines may be based on these symptom classifications:

  • Mild intermittent: No daily medication is needed but a short-acting beta2 agonist may be used when needed to treat symptoms.
  • Mild persistent: Daily long-term medication may be prescribed.
  • Moderate persistent: Two medications may be prescribed, including a long-term medication to control inflammation and a short-acting medication to use when symptoms are more severe.
  • Severe persistent: Multiple long-term control medications are required.

When asthma symptoms worsen, medication is increased. When asthma symptoms are controlled, less medication is needed. It is very important to discuss any desired changes to the medication schedule with the doctor. The medication dose should never be changed without the doctor's approval. The condition can worsen if certain medications are not taken.

Inhaled medications have a special inhaler that meters the dose. The inhaler may have a spacer that holds the burst of medication until it is inhaled. Patients will be instructed on how to properly use an inhaler to ensure that it will deliver the right amount of medication.

A home nebulizer, also known as a breathing machine, may be used to deliver asthma medications at home. The nebulizer changes medication from liquid form to a mist. The child wears a face mask to breathe in the medications. Nebulizer treatments generally take seven to 10 minutes.

Quick relief medications include short-acting, inhaled beta2 agonists and anticholinergics. Long-acting medications include leukotriene modifiers, mast cell stabilizers, inhaled and oral corticosteroids, long-acting beta2 agonists, and methylxanthines.

SHORT-ACTING BETA-2 AGONISTS These drugs, which are bronchodilators, open the airways by relaxing the muscles around the airways that have tightened (bronchospasm). The short-acting forms of beta-receptor agonists are the best choice for relieving sudden attacks of asthma and for preventing attacks triggered by exercise. These drugs generally start acting within minutes, but their effects last only four to six hours (although longer-acting forms are being developed). They may be taken by mouth, inhaled, or injected.

ANTICHOLINERGICS Anticholinergics are medications that open the airways by relaxing the muscle bands that tighten around the airways. They also suppress mucus production. They do not provide immediate relief, but can be used to control severe attacks when added to an inhaled beta-receptor agonist.

LEUKOTRIENE MODIFIERS Leukotriene modifiers, also called antileukotrienes, can be used in place of steroids for older children who have a mild degree of asthma that persists. They work by counteracting leukotrienes, substances released by white blood cells in the lung that cause the air passages to constrict and promote mucus secretion.

MAST CELL STABILIZERS Available only in inhaled form, mast cell stabilizers, such as cromolyn and nedocromil, prevent asthma symptoms. These anti-inflammatory drugs are often given to children as the initial treatment to prevent asthmatic attacks over the long term. They can also prevent attacks when given before exercise or when exposure to an allergen cannot be avoided. They are not effective until three to four weeks after therapy is started. These medications need to be taken two to four times a day.

STEROIDS These drugs, which resemble natural body hormones, block inflammation. Steroids are extremely effective in relieving asthma symptoms and can control even severe cases over the long term while maintaining good lung function. When steroids are taken by inhalation for a long period, asthma attacks become less frequent as the airways become less sensitive to allergens. Besides being inhaled, steroids may be taken by mouth or injected, to rapidly control severe asthma. Steroids are the strongest class of asthma medications and can cause numerous side-effects, including bleeding from the stomach, loss of calcium from bones, cataracts in the eye, and a diabetes-like state. Patients using steroids for lengthy periods also may have problems with wound healing, weight gain, and mental disorders. In children, growth may be slowed. To prevent serious side effects, the child will have periodic monitoring tests.

LONG-ACTING BETA-2 AGONISTS Long-acting beta-2 agonists are used for better controlnot reliefof asthma symptoms. The medications take longer to work and the effects last longer, up to 12 hours.

METHYLXANTHINES Theophylline is the chief methylxanthine drug. It may exert some anti-inflammatory effect, and is especially helpful in controlling nighttime symptoms of asthma. If a patient cannot use an inhaler to maintain long-term control, sustained-release theophylline is a good alternative. The blood levels of the drug must be measured periodically, as too high of a dose can cause an abnormal heart rhythm or convulsions.

OTHER DRUGS Some inhalers contain a combination of two different medications that can be delivered together to shorten treatment times and decrease the number of inhalers that need to be purchased. Clinical trials are continuously evaluating new asthma medications.

IMMUNOTHERAPY If a patient's asthma is caused by an allergen that cannot be avoided, or if medications have not been effective in controlling symptoms, immunotherapy (also called allergy shots ) may be considered. Immunotherapy is helpful when symptoms tend to occur throughout all or most of the year. Typically, increasing amounts of the allergen are injected over a period of three to five years, so that the body can build up an effective immune response. There is a risk that this treatment may cause the airways to become narrowed and bring on an asthmatic attack.

An international conference, Immunotherapy in Allergic Asthma, hosted by the American College of Allergy, Asthma, and Immunology (ACAII) in 2000 concluded that immunotherapy is an effective treatment for allergic asthma and can prevent the onset of asthma in children with allergic rhinitis . The Preventive Allergy Treatment study, published in 2002, confirmed the ACAII conference conclusions, documenting that immunotherapy reduces the risk of developing asthma and reduces lung airway inflammation in children with hay fever, a condition that predisposes them to asthma.

Managing asthmatic attacks

Urgent measures to control asthma attacks and ongoing treatment to prevent attacks are equally important. No matter how severe a person's asthma, quick-relief medications must be readily available to treat acute symptoms. If the patient's asthma symptoms are present most of the time, an anti-inflammatory medication should be used regularly.

A severe asthma attack should be treated as quickly as possible. It is most important for a patient suffering an acute attack to be given extra oxygen. Rarely, it may be necessary to use a mechanical ventilator to help the patient breathe. A beta-receptor agonist is inhaled repeatedly or continuously. A steroid is given if the patient's symptoms do not improve promptly and completely. Steroids also may help if a viral infection caused severe asthmatic symptoms. A course of steroid therapy, given after the attack is over, will make a recurrence less likely.

Starting treatment at home, rather than in a hospital, minimizes delays and helps the patient gain a sense of control over the disease. When deciding whether a patient should be hospitalized, the past history of acute attacks, severity of symptoms, current medication, and availability of adequate support at home must be taken into account.

Maintaining control

Children with asthma should follow up with their doctor every one to six months, depending on the frequency of attacks. During the follow-up visits, the child's lung function should be measured by spirometry to make sure treatment goals are being met. Once asthma has been controlled for several weeks or months, the child's physician may adjust the medication dosage. If there is no clear improvement with the current treatment plan, another treatment plan should be established.

All patients with asthma should learn how to monitor their symptoms so that they will know when an attack is starting. Symptoms can be monitored with a peak flow meter (also called a peak expiratory flow meter). To effectively follow the instructions for using a peak flow meter, the child should be at least five years old. The peak flow meter measures the child's airflow when he or she blows into it quickly and forcefully. The peak flow meter can be used to determine when to call the doctor or seek emergency care.

Knowing the child's allergens or triggers will help parents reduce exposure by making improvements in the home environment. Specific guidelines may include reducing indoor humidity, using allergen-impermeable bedding covers, minimizing the use of carpet and upholstered furniture, and minimizing pet exposure. For more information, see the Prevention section.

All patients with asthma should have a written action plan to follow if symptoms suddenly become worse, including how to adjust medication and when to seek medical help. A Northwestern University study indicates that asthma symptoms and the need for emergency medications in children can be greatly reduced by using a planned-care method. This method involves regularly scheduled visits with specially trained nurses to help the patient and family learn how to anticipate and improve the management of asthma symptoms.

The health care provider should write out an asthma treatment plan for the child's school personnel or care providers. The plan should detail the early warning signs of an asthma attack, what medications the student uses and how they are taken, and when to contact the doctor or seek emergency care. Children with asthma often need medication at school to control acute symptoms or to prevent exercise-induced attacks. Proper management will usually allow a child to take part in play activities. Only as a last resort should activities be limited.

Alternative treatment

Alternative and complementary therapies include approaches considered to be outside the mainstream of traditional health care. Alternative treatments for asthma include yoga to control breathing and relieve stress and acupuncture to reduce asthma attacks and improve lung function. Biofeedback, which teaches patients how to direct mental thoughts to influence physical functions, may be helpful for some patients. For example, learning to increase the amount of air inhaled may help some patients reduce fear and anxiety. Some Chinese traditional herbs, such as ding-chan tang, have been thought to help decrease inflammation and relieve bronchospasm.

Before learning or practicing any particular technique, it is important for the parent or caregiver and child to learn about the therapy, its safety and effectiveness, potential side effects, and the expertise and qualifications of the practitioner. Although some practices are beneficial, others may be harmful to certain patients.

Relaxation techniques and dietary supplements should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these alternative treatments with the child's doctor to determine the techniques and remedies that may be beneficial.

Nutritional concerns

Some children have reportedly experienced improved symptoms by limiting dairy products and sugar in the diet. Some studies show that vitamin C helps improve asthma symptoms.

Food additives may trigger asthma symptoms in some children, although this is rare. If the parent suspects that certain foods trigger asthma symptoms in the child, the pediatrician may recommend keeping a food diary for a few weeks to identify problematic foods. Allergy skin testing may be recommended to rule out foods that may trigger asthma symptoms.

Prognosis

Although there is no cure for asthma, it can be treated and managed. Most patients with asthma respond well and are able to lead relatively normal lives when the best drug or combination of drugs is found. Asthma should not be a progressive, disabling disease; a child with asthma can have normal or near-normal lung function with the proper treatment.

Some children stop having attacks as they grow and their airways get bigger. About 50 percent of children have less frequent and less severe attacks as they grow older. However, symptoms can recur when the child reaches his or her thirties or forties.

A small number of patients will have progressively more difficulty breathing. These patients have an increased risk of respiratory failure, and they must receive intensive treatment. Asthma can be a deadly disease if it is not managed properly; an estimated 5,000 people die each year from asthma or its complications.

Prevention

Prolonged breastfeeding in infants for six to 12 months has been shown to reduce the child's likelihood for developing persistent asthma.

Minimizing exposure to allergens

There are a number of ways parents can reduce or prevent a child's exposure to the common allergens and irritants that provoke asthmatic attacks:

  • If the child is sensitive to a family pet, the pet should be removed or kept out of the child's bedroom (with the bedroom door closed). The pet should be kept away from carpets and upholstered furniture. All products made from feathers should be removed. An air filter should be used on air ducts in the child's room.
  • To reduce exposure to house dust mites, wall-to-wall carpeting should be removed, humidity should be kept down, and special pillow and mattress covers should be used. The number of stuffed toys should be reduced, and they should be washed in hot water weekly. Bedding should also be washing weekly in hot water, and dried in a dryer on the hot setting. The child should not be allowed to sleep on upholstered furniture. Carpets should be removed from the child's bedroom.

KEY TERMS

Acute Refers to a disease or symptom that has a sudden onset and lasts a relatively short period of time.

Allergen A foreign substance that provokes an immune reaction or allergic response in some sensitive people but not in most others.

Allergy A hypersensitivity reaction in response to exposure to a specific substance.

Alveoli The tiny air sacs clustered at the ends of the bronchioles in the lungs in which oxygen-carbon dioxide exchange takes place.

Anti-inflammatory A class of drugs, including nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids, used to relieve swelling, pain, and other symptoms of inflammation.

Atopy A state that makes persons more likely to develop allergic reactions of any type, including the inflammation and airway narrowing typical of asthma.

Bronchial tubes The major airways to the lungs and their main branches.

Bronchioles Small airways extending from the bronchi into the lobes of the lungs.

Bronchospasm The tightening of the muscle bands that surround the airways, causing the airways to narrow.

Dander Loose scales shed from the fur or feathers of household pets and other animals. Dander can cause allergic reactions in susceptible people.

Dust mites Tiny insects, unable to be seen without a microscope, that are present in carpet, stuffed animals, upholstered furniture, and bedding, including pillows, mattresses, quilts, and other bed covers. Dust mites are one of the most common asthma triggers. They grow best in areas with high humidity.

Hypersensitivity A condition characterized by an excessive response by the body to a foreign substance. In hypersensitive individuals even a tiny amount of allergen can cause a severe allergic reaction.

Inflammation Pain, redness, swelling, and heat that develop in response to tissue irritation or injury. It usually is caused by the immune system's response to the body's contact with a foreign substance, such as an allergen or pathogen.

Peak flow measurement Measurement of the maximum rate of airflow attained during a forced vital capacity determination.

Pollen A fine, powdery substance released by plants and trees; an allergen.

Spirometry A test using an instrument called a spirometer that measures how much and how fast the air is moving in and out of a patient's lungs. Spirometry can help a physician diagnose a range of respiratory diseases, monitor the progress of a disease, or assess a patient's response to treatment.

Trigger Any situation or substance that causes asthma symptoms to start or become worse.

  • If cockroach allergen is causing asthma attacks, the roaches should be killed (using poison, traps, or boric acid rather than chemicals). Food or garbage should not be exposed.
  • Indoor air may be kept clean by vacuuming carpets once or twice a week (with the child absent), avoiding humidifiers, and using air conditioning during warm weather (so that windows remain closed).
  • To reduce exposure to mold, indoor humidity should be decreased to less than 50 percent, leaky faucets and pipes should be repaired, and vaporizers avoided.
  • Family members should quit smoking and others should not be allowed to smoke in the house or near the child.
  • The child should not exercise outdoors when air pollution levels are high.

Parental concerns

Parents should take an open and honest approach when explaining asthma to their child. They should explain that asthma does not define or limit the child. The success of the child's treatment plan will depend on parental guidance and support. As a child ages, the responsibility for personal asthma management can be increased. For example, toddlers can mimic treatment on a toy or doll; preschoolers can help parents in peak flow monitoring and discuss symptoms with them; schoolaged children can begin to take medications on their own (while supervised); and adolescents can be nearly independent in following the structured management plan.

Parents should stress the consequences of improper symptom management with their child. The main concern with older children is peer pressure and the desire to fit in; therefore, symptoms may not be reported accurately and medications may not be taken to avoid comments from peers or appearing different. Parents may want to counteract peer pressure by offering a contract that outlines the management plan and lists specific rewards and consequences.

Parents should work with school personnel to foster a supportive environment that so the child's symptoms can be managed properly. A specific action plan can be developed for school by the child's doctor. Parents should inform school personnel about the child's specific allergens and asthma triggers so steps can be taken to help the child avoid them at school. Students who are able to recognize symptoms requiring medication and know how to use their inhaler properly should be permitted to keep the medication with them. For younger children, parents must ensure that school personnel know how to administer the child's medications.

Asthma should not be used as an excuse to avoid exercise. Sometimes children with asthma avoid school activities because they are afraid of being embarrassed if symptoms occur. Parents should encourage athletic or physical activity participation and talk to gym teachers or coaches to ensure they understand the child's symptoms and treatment protocol. They should make sure the child knows what to do if exercise causes symptoms. Swimming is generally well-tolerated by many people with asthma because it is usually performed in a warm, moist environment. Other activities that involve brief, intermittent periods of exertion, such as volleyball, gymnastics, baseball, walking, and wrestling are usually well-tolerated. Cold-weather sports , such as skiing, ice skating, or hockey, may be not be tolerated as well. The child's doctor can provide specific exercise recommendations and guidelines.

See also Allergy shots.

Resources

BOOKS

American Medical Association. The American Medical Association Essential Guide for Asthma (Better Health for 2003) Pocket, 2000.

Fanta, Christopher H., et al. The Harvard Medical School Guide to Taking Control of Asthma. New York, NY: Free Press, 2003.

Wolf, Rauol. Essential Pediatric Allergy, Asthma, and Immunology. New York, NY: McGraw-Hill Professional, 2004.

ORGANIZATIONS

Allergy and Asthma Network/Mothers of Asthmatics America, Inc. 2751 Prosperity Ave., Suite 150, Fairfax, VA 22031. (800) 878-4403. Web site: <www.aanma.org.>.

American Academy of Allergy, Asthma and Immunology (AAAAI). 611 E. Wells St., Milwaukee, WI 53202. (800) 822-ASTHMA or (414) 272-6071. Web site: <www.aaaai.org>.

American College of Asthma, Allergy and Immunology (AACI). 85 W. Algonquin Rd., Suite 550, Arlington Hts., IL 60005. (800) 842-7777. Web site: <www.aaci.org.>.

American Lung Association. 1740 Broadway, New York, NY 10019. (800) 586-4872. Web site: <www.lungusa.org.>.

Asthma and Allergy Foundation of America. 1233 20th Street, NW, Suite 402, Washington, DC 20036. (800) 727-8462 or (202) 466-7643. Web site: <www.aafa.org>.

National Asthma Education Program. National Heart, Lung and Blood Institute Information Center. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 592-8573. Web site: <www.nhlbi.nih.gov/about/naepp/>.

National Institute of Allergy and Infectious Diseases. NIAID Office of Communications and Public Liaison, Building 31, Room 7A-50, 31 Center Dr., MSC 2520, Bethesda, MD 20892-2520. Web site: <www.niaid.nih.gov>.

David A. Cramer, M.D. Angela M. Costello

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Cramer, David; Costello, Angela. "Asthma." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 30 Jul. 2016 <http://www.encyclopedia.com>.

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Cramer, David; Costello, Angela. "Asthma." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Retrieved July 30, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3447200066.html

Asthma

Asthma

Definition

Asthma is a chronic inflammatory disease of the airways in the lungs. This inflammation periodically causes the airways to narrow, producing wheezing and breath-lessness sometimes to the point where the patient gasps for air. This obstruction of the air flow either stops spontaneously or responds to a wide range of treatments. Continuing inflammation makes asthmatics hyper-responsive to such stimuli as cold air, exercise , dust, pollutants in the air, and even stress or anxiety .

Description

Between 16 and 17 million Americans have asthma and the number has been rising since 1980. As many as 9 million U.S. children under age 18 may have asthma. Blacks, Hispanics, American Indians, and Alaskan natives had higher rates of asthma-control problems than whites or Asians in the United States.

The changes that take place in the lungs of asthmatics make their airways (the bronchi and the smaller bronchioles) hyper-reactive to many different types of stimuli that do not affect healthy lungs. In an asthma attack, the muscle tissue in the walls of the bronchi go into spasm, and the cells that line the airways swell and secrete mucus into the air spaces. Both these actions cause the bronchi to narrow, a change that is called bronchoconstriction. As a result, an asthmatic person has to make a much greater effort to breathe.

Cells in the bronchial walls, called mast cells, release certain substances that cause the bronchial muscle to contract and stimulate mucus formation. These substances, which include histamine and a group of chemicals called leukotrienes, also bring white blood cells into the area. Many patients with asthma are prone to react to substances such as pollen, dust, or animal dander; these are called allergens. Many people with asthma do not realize that allergens are triggering their attacks. On the other hand, asthma also affects many patients who are not allergic in this way.

Asthma usually begins in childhood or adolescence, but it also may first appear in adult life. While the symptoms may be similar, certain important aspects of asthma are different in children and adults. When asthma begins in childhood, it often does so in a child who is likely, for genetic reasons, to become sensitized to common allergens in the environment. Such a child is known as an atopic person. In 2004, scientists in Helsinki, Finland, identified two new genes that cause atopic asthma. The discovery might lead to earlier prediction of asthma in children and adults. When these children are exposed to dust, animal proteins, fungi, or other potential allergens, they produce a type of antibody that is intended to engulf and destroy the foreign materials. This has the effect of making the airway cells sensitive to particular materials. Further exposure can lead rapidly to an asthmatic response. This condition of atopy is present in at least one third and as many as one half of the general population. When an infant or young child wheezes during viral infections , the presence of allergy (in the child or a close relative) is a clue that asthma may well continue throughout childhood.

Allergenic materials may also play a role when adults become asthmatic. Asthma can start at any age and in a wide variety of situations. Many adults who are not allergic have such conditions as sinusitis or nasal polyps, or they may be sensitive to aspirin and related drugs. Another major source of adult asthma is exposure at work to animal products, certain forms of plastic, wood dust, metals, and environmental pollution.

Causes & symptoms

In most cases, asthma is caused by inhaling an allergen that sets off the chain of biochemical and tissue changes leading to airway inflammation, bronchoconstriction, and wheezing. Because avoiding (or at least minimizing) exposure is the most effective way of treating asthma, it is vital to identify which allergen or irritant is causing symptoms in a particular patient. Once asthma is present, symptoms can be set off or made worse if the patient also has rhinitis (inflammation of the lining of the nose) or sinusitis. When, for some reason, stomach acid passes back up the esophagus in a reaction called acid reflux, this condition also can make asthma worse. In addition, a viral infection of the respiratory tract can inflame an asthmatic reaction. Aspirin and drugs called beta-blockers, often used to treat high blood pressure, also can worsen the symptoms of asthma. But the most important inhaled allergens giving rise to attacks of asthma are:

  • animal dander
  • dust mites
  • fungi (molds) that grow indoors
INHALED ALLERGENS MOST OFTEN TRIGGERING ASTHMA ATTACKS
Air pollutants
Animal dander
Cockroach allergens
Dust mites
Indoor fungi (molds)
Occupational allergens such as chemicals, fumes, particles of industrial materials
Pollen
  • cockroach allergens
  • pollen
  • occupational exposure to chemicals, fumes, or particles of industrial materials
  • tobacco smoke
  • air pollutants

In addition, there are three important factors that regularly produce attacks in certain asthmatic patients, and they may sometimes be the sole cause of symptoms. They are:

  • inhaling cold air (cold-induced asthma)
  • exercise-induced asthma (in certain children, asthma attacks are caused simply by exercising)
  • stress or a high level of anxiety

Wheezing often is obvious, but mild asthmatic attacks may be confirmed when the physician listens to the patient's chest with a stethoscope. Besides wheezing and being short of breath, the patient may cough or report a feeling of tightness in the chest. Children may have itching on their back or neck at the start of an attack. Wheezing often is loudest when the patient exhales. Some asthmatics are free of symptoms most of the time but may occasionally be short of breath for a brief time. Others spend much of their days (and nights) coughing and wheezing until properly treated. Crying or even laughing may bring on an attack. Severe episodes often are seen when the patient gets a viral respiratory tract infection or is exposed to a heavy load of an allergen or irritant. Asthmatic attacks may last only a few minutes or can go on for hours or even days. Being short of breath may cause a patient to become very anxious, sit upright, lean forward, and use the muscles of the neck and chest wall to help breathe. The patient may be able to say only a few words at a time before stopping to take a breath. Confusion and a bluish tint to the skin are clues that the

OCCUPATIONS ASSOCIATED WITH ASTHMA
Animal Handling
Bakeries
Health Care
Jewelry Making
Laboratory Work
Manufacturing Detergents
Nickel Plating
Soldering
Snow Crab and Egg Processing
Tanneries

oxygen supply is much too low and that emergency treatment is needed. In a severe attack, some of the air sacs in the lung may rupture so that air collects within the chest, which makes it even harder to breathe. The good news is that almost always, even patients with the most severe attacks will recover completely.

Diagnosis

Apart from listening to the patient's chest, the examiner should look for maximum chest expansion while taking in air. Hunched shoulders and contracting neck muscles are other signs of narrowed airways. Nasal polyps or increased amounts of nasal secretions are often noted in asthmatic patients. Skin changes, like dermatitis or eczema , are a clue that the patient has allergic problems. Inquiring about a family history of asthma or allergies can be a valuable indicator of asthma. A test called spirometry measures how rapidly air is exhaled and how much is retained in the lungs. Repeating the test after the patient inhales a drug that widens the air passages (a bronchodilator) will show whether the narrowing of the airway is reversible, which is a very typical finding in asthma. Often patients use a related instrument, called a peak flow meter, to keep track of asthma severity when at home.

Frequently, it is difficult to determine what is triggering asthma attacks. Allergy skin testing may be used, although an allergic skin response does not always mean that the allergen being tested is causing the asthma. Also, the body's immune system produces an antibody to fight off the allergen, and the amount of antibody can be measured by a blood test. The blood test will show how sensitive the patient is to a particular allergen. If the diagnosis is still in doubt, the patient can inhale a suspect allergen while using a spirometer to detect airway narrowing. Spirometry also can be repeated after a bout of exercise if exercise-induced asthma is a possibility. A chest x-ray will help rule out other disorders.

Treatment

There are many alternative treatments available for asthma that have shown promising results. One strong argument for these treatments is that they try to avoid the drugs that allopathic treatment (combating disease with remedies to produce effects different from those produced by the disease) relies upon, which can be toxic and addictive. Mainstream journals have reported on the toxicity of asthma pharmaceuticals. A 1995 New Zealand study showed that before 1940, death from asthma was very low, but that the death rate promptly increased with the introduction of bronchodilators. The New England Journal of Medicine in 1992 reported that albuterol and other asthma drugs cause the lungs to deteriorate when used regularly. A 1989 study in the Annals of Internal Medicine showed that respiratory therapists, who are exposed to bronchodilator sprays, develop asthma five times more often than other healthcare professionals, which could imply that the drugs themselves may induce asthma. Theophylline, another popular drug, has been reported to cause personality changes in users. Steroids can also have negative effects on many systems in the body, particularly the hormonal system. Thus, natural and non-toxic methods for treating asthma are the preferred first choice of alternative practitioners, while drugs are used to manage extreme cases and emergencies.

Alternative medicine tends to view asthma as the body's protective reaction to environmental agents and pollutants. As such, the treatment goal is often to restore balance to and strengthen the entire body and provide specific support to the lungs, immune and hormonal systems. Asthma sufferers can help by keeping a diary of asthma attacks in order to determine environmental and emotional factors that may be contributing to their condition.

Alternative treatments have minimal side effects, are generally inexpensive, and are convenient forms of selftreatment. They also can be used alongside allopathic treatments to improve their effectiveness and lessen their negative side effects.

Dietary and nutritional therapies

Some alternative practitioners recommend cutting down on or eliminating dairy products from the diet, as

these increase mucus secretion in the lungs and are sources of food allergies. Other recommendations include avoiding processed foods, refined starches and sugars, and foods with artificial additives and sulfites. Diets should be high in fresh fruits, vegetables, and whole grains, and low in salt. Asthma sufferers should experiment with their diets to determine if food allergies are playing a role in their asthma. Some studies have shown that a sustained vegan (zero animal foods) diet can be effective for asthma, as it does not contain the animal products that frequently cause food allergies and contain chemical additives. A vegan diet also eliminates a fatty acid called arachidonic acid, which is found in animal products and is believed to contribute to allergic reactions. A 1985 Swedish study showed that 92% of patients with asthma improved significantly after one year on a vegan diet. On the other hand, some people feel weaker on a vegan diet. In addition, many people are allergic to vegetables rather than to meat.

Plenty of water should also be drunk by asthma sufferers, as water helps to keep the passages of the lungs moist. Onions and garlic contain quercetin, a flavonoid (a chemical compound/biological response modifier) that inhibits the release of histamine, and should be a part of an asthmatic's diet. Quercetin also is available as a supplement, and should be taken with the digestive enzyme bromelain to increase its absorption.

As nutritional therapy, vitamins A, C and E have been touted as important. Also, the B complex vitamins, particularly B6 and B12, may be helpful for asthma, as well as magnesium, selenium , and an omega-3 fatty acid supplement such as flaxseed oil. A good multivitamin supplement also is recommended. In 2004, a study of supplements at Cornell University showed that high levels of beta-carotene and vitamin C along with selenium lowered risk of asthma. However, the same study found that vitamin E had no effect.

Herbal remedies

Chinese medicine has traditionally used ma huang, or ephedra , for asthma attacks. It contains ephedrine, which is a bronchodilator used in many drugs. However, the U.S. Food and Drug Administration (FDA) issued a ban on the sale of ephedra that took effect in April 2004 because it was shown to raise blood pressure and stress the circulatory system, resulting in heart attacks and strokes for some users. Ginkgo has been shown to reduce the frequency of asthma attacks, and licorice is used in Chinese medicine as a natural decongestant and expectorant. There are many formulas used in traditional Chinese medicine to prevent or ease asthma attacks, depending on the specific Chinese diagnosis given by the practitioner. For example, ma huang is used to treat socalled "wind-cold" respiratory ailments.

Other herbs used for asthma include lobelia , also called Indian tobacco; nettle , which contains a natural antihistamine; thyme ; elecampane mullein : feverfew ; passionflower : saw palmetto : and Asian ginseng. Coffee and tea have been shown to reduce the severity of asthma attacks because caffeine works as a bronchodilator. Tea also contains minute amounts of theophylline, a major drug used for asthma. Ayurvedic (traditional East Indian) medicine recommends the herb Tylophora asthmatica.

Mind/body approaches

Mind/body medicine has demonstrated that psychological factors play a complex role in asthma. Emotional stress can trigger asthma attacks. Mind/body techniques strive to reduce stress and help asthma sufferers manage the psychological component of their condition. A 1992 study by Dr. Erik Peper at the Institute for Holistic Healing Studies in San Francisco used biofeedback , a treatment method that uses monitors to reveal physiological information to patients, to teach relaxation and deep breathing methods to 21 asthma patients. Eighty percent of them subsequently reported fewer attacks and emergency room visits. A 1993 study by Kaiser Permanente in Northern California worked with 323 adults with moderate to severe asthma. Half the patients got standard care while the other half participated in support groups. The support group patients had cut their asthma-related doctor visits in half after two years. Some other mind/body techniques used for asthma include relaxation methods, meditation, hypnotherapy ,, mental imaging, psychotherapy , and visualization.

Yoga and breathing methods

Studies have shown that yoga significantly helps asthma sufferers, with exercises specifically designed to expand the lungs, promote deep breathing, and reduce stress. Pranayama is the yogic science of breathing, which includes hundreds of deep breathing techniques. These breathing exercises should be done daily as part of any treatment program for asthma, as they are a very effective and inexpensive measure.

Controlled exercise

Many people believe that those with asthma should not exercise. This is particularly true among parents of children with asthma. In a 2004 study, researchers reported that 20% of children with asthma do not get enough exercise. Many parents believe it is dangerous for their children with asthma to exercise, but physical activity benefits all children, including those with asthma. Parents should work with the child's healthcare provider and any coach or organized sport leader to carefully monitor his or her activities.

Acupuncture

Acupuncture can be an effective treatment for asthma. It is used in traditional Chinese medicine along with dietary changes. Acupressure can also be used as a self-treatment for asthma attacks and prevention. The Lung 1 points, used to stimulate breathing, can be easily found on the chest. These are sensitive, often knotted spots on the muscles that run horizontally about an inch below the collarbone, and about two inches from the center of the chest. The points can be pressed in a circular manner with the thumbs, while the head is allowed to hang forward and the patient takes slow, deep breaths. Reflexology also uses particular acupressure points on the hands and feet that are believed to stimulate the lungs.

Other treatments

Aromatherapists recommend eucalyptus, lavender, rosemary , and chamomile as fragrances that promote free breathing. In Japan, a common treatment for asthma is administering cold baths. This form of hydrotherapy has been demonstrated to open constricted air passages. Massage therapies such as Rolfing can help asthma sufferers as well, as they strive to open and increase circulation in the chest area. Homeopathy uses the remedies Arsenicum album, Kali carbonicum, Natrum sulphuricum, and Aconite.

Allopathic treatment

Allopaths recommend that asthma patients should be periodically examined and have their lung functions measured by spirometry. The goals are to prevent troublesome symptoms, to maintain lung function as close to normal as possible, and to allow patients to pursue their normal activities, including those requiring exertion. The best drug therapy is that which controls asthmatic symptoms while causing few or no side effects.

Drugs

The chief methylxanthine drug is theophylline. It may exert some anti-inflammatory effect and is especially helpful in controlling nighttime symptoms of asthma. When, for some reason, a patient cannot use an inhaler to maintain long-term control, sustained-release theophylline is a good alternative. The blood levels of the drug must be measured periodically, as too high a dose can cause an abnormal heart rhythm or convulsions.

Beta-receptor agonists (drugs that trigger cell response) are bronchodilators. They are the drugs of choice for relieving sudden attacks of asthma and for preventing attacks from being triggered by exercise. Some agonists, such as albuterol, act mainly in lung cells and have little effect on the heart and other organs. These drugs generally start acting within minutes, but their effects last only four to six hours. They may be taken by mouth, inhaled, or injected. In 2004, a new lower concentration of albuterol was approved by the FDA for children ages two to 12.

Steroids are drugs that resemble natural body hormones. They block inflammation and are effective in relieving symptoms of asthma. When steroids are taken by inhalation for a long period, asthma attacks become less frequent as the airways become less sensitive to allergens. Steroids are the strongest medicine for asthma, and can control even severe cases over the long term and maintain good lung function. However, steroids can cause numerous side effects, including bleeding from the stomach, loss of calcium from bones, cataracts in the eye, and a diabetes-like state. Patients using steroids for lengthy periods may also have problems with wound healing, may gain weight, and may suffer mental problems. In children, growth may be slowed. Besides being inhaled, steroids may be taken by mouth or injected, to rapidly control severe asthma.

Leukotriene modifiers are among a newer type of drug that can be used in place of steroids, for older children or adults who have a mild degree of persistent asthma. They work by counteracting leukotrienes, which are substances released by white blood cells in the lung that cause the air passages to constrict and promote mucus secretion. Other drugs include cromolyn and nedocromil, which are anti-inflammatory drugs that often are used as initial treatments to prevent long-term asthmatic attacks in children. Montelukast sodium (Singulair) is a drug taken daily that is used to help prevent asthma attacks rather than to treat an acute attack. In 2004, the FDA approved an oral granule formula of Singulair for young children.

If a patient's asthma is caused by an allergen that cannot be avoided and it has been difficult to control symptoms by drugs, immunotherapy may be worth trying. In a typical course of immunotherapy, increasing amounts of the allergen are injected over a period of three to five years, so that the body can build up an effective immune response. There is a risk that this treatment may itself cause the airways to become narrowed and bring on an asthmatic attack. Not all experts are enthusiastic about immunotherapy, although some studies have shown that it reduces asthmatic symptoms caused by exposure to dust mites, ragweed pollen, and cats.

Managing asthmatic attacks

A severe asthma attack should be treated as quickly as possible. It is most important for a patient suffering an acute attack to be given extra oxygen. Rarely, it may be necessary to use a mechanical ventilator to help the patient breathe. A beta-receptor agonist is inhaled repeatedly or continuously. If the patient does not respond promptly and completely, a steroid is given. A course of steroid therapy, given after the attack is over, will make a recurrence less likely.

Long-term allopathic treatment for asthma is based on inhaling a beta-receptor agonist using a special inhaler that meters the dose. Patients must be instructed in proper use of an inhaler to be sure that it will deliver the right amount of drug. Once asthma has been controlled for several weeks or months, it is worth trying to cut down on drug treatment, but this tapering must be done gradually. The last drug added should be the first to be reduced. Patients should be seen every one to six months, depending on the frequency of attacks. Starting treatment at home, rather than in a hospital, makes for minimal delay and helps the patient to gain a sense of control over the disease. All patients should be taught how to monitor their symptoms so that they will know when an attack is starting. Those with moderate or severe asthma should know how to use a flow meter. They also should have a written plan to follow if symptoms suddenly become worse, including how to adjust their medication and when to seek medical help. If more intense treatment is necessary, it should be continued for several days. When deciding whether a patient should be hospitalized, the physician must take into account the patient's past history of acute attacks, severity of symptoms, current medication, and the availability of good support at home.

Expected results

Most patients with asthma respond well when the best treatment or combination of treatments is found and they are able to lead relatively normal lives. Patients who take responsibility for their condition and experiment with various treatments have good chances of keeping symptoms minimal. Having urgent measures to control asthma attacks and ongoing treatment to prevent attacks are important as well. More than one half of affected children stop having attacks by the time they reach 21 years of age. Many others have less frequent and less severe attacks as they grow older. A small minority of patients will have progressively more trouble breathing. Because they run a risk of going into respiratory failure, they must receive intensive treatment.

Prevention

Prevention is extremely important in the treatment of asthma, which includes eliminating all possible allergens from the environment and diet. Homes and work areas should be as dust and pollutant-free as possible. Areas can be tested for allergens and high-quality air filters can be installed to clean the air. If the patient is sensitive to a family pet, removing the animal or at least keeping it out of the bedroom (with the bedroom door closed) is advised. Keeping the pet away from carpets and upholstered furniture, and removing all feathers also helps. To reduce exposure to dust mites, it is recommended to remove wall-to-wall carpeting, keep the humidity low, and use special pillows and mattress covers. Cutting down on stuffed toys, and washing them each week in hot water, is advised for children with asthma. If cockroach allergen is causing asthma attacks, controlling the roaches (using traps or boric acid rather than chemicals) can help.

It is important to not to leave food or garbage exposed. Keeping indoor air clean by vacuuming carpets once or twice a week (with the asthmatic person absent), and avoiding use of humidifiers is advised. Those with asthma should avoid exposure to tobacco smoke and should not exercise outside when air pollution levels are high. When asthma is related to exposure at work, taking all precautions, including wearing a mask and, if necessary, arranging to work in a safer area, is recommended. For chronic sufferers who live in heavily polluted areas, moving to less polluted regions may even be a viable alternative.

Resources

BOOKS

Bock, Steven J. Natural Relief for Your Child's Asthma. New York: HarperPerennial, 1999.

Cutler, Ellen W. Winning the War against Asthma and Allergies. New York: Delmar, 1998.

PERIODICALS

Allergy and Asthma Magazine. 702 Marshall St., Suite 611. Redwood City, CA 94063. (605) 780-0546.

"Allergy Season Can Mean Trouble." Respiratory Therapeutics Week (April 19, 2004):9.

"Asthma Antioxidants." Better Nutrition (May 2004):2627.

"Children with Asthma Inactive Due to Parental Health Beliefs, Disease Severity." Obesity, Fitness & Wellness Week (May 1, 2004):8.

"Identification of New Asthma Genes Demonstrates Model for Improved Patient Care." Drug Week (April 30, 2004):27.

McNamara, Daniel. "Singulair." Family Practice News (February 1, 2004):108109.

"Nine Million U.S. Children Diagnosed With Asthma, New Report Finds." Medical Letter on the CDC & FDA (April 25, 2004):11.

"Patent Granted for Pediatric Asthma Medication." Health & Medicine Week (April 12, 2004):552.

Ressel, Genevieve. "FDA Issues Regulation Prohibiting Sale of Dietary Supplements Containing Ephedra." American Family Physician (March 15, 2004):1343.

"U.S. Asthma Rates on the Rise." Medical Letter on the CDC & FDA (March 28, 2004):11.

ORGANIZATIONS

Asthma and Allergy Foundation of America. 1125 15th St. NW, Suite 502. Washington, DC 20005. 800-7ASTHMA. <http://www.aafa.org>.

Center for Complementary and Alternative Medicine Research in Asthma, Allergy, and Immunology. University of California at Davis. 3150B Meyer Hall. Davis, CA 95616. (916) 752-6575. <http://www-camra.ucdavis.edu>.

Douglas Dupler

Teresa G. Odle

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Asthma

Asthma

Definition

Asthma is a chronic (long-lasting) inflammatory disease of the airways. In those susceptible to asthma, this inflammation causes the airways to narrow periodically. This, in turn, produces wheezing and breathlessness, sometimes to the point where the patient gasps for air. Obstruction to air flow either stops spontaneously or responds to a wide range of treatments, but continuing inflammation makes the airways hyper-responsive to stimuli such as cold air, exercise, dust mites, pollutants in the air, and even stress and anxiety.

Description

Between 17 million and 26 million Americans have asthma, and the number seems to be increasing. In about 1992, the number with asthma was about 10 million, and had risen 42% from 1982, just 10 years prior. Not only is asthma becoming more frequent, but it also is a more severe disease than before, despite modern drug treatments. Asthma accounts for almost 500,000 hospitalizations, two million emergency department visits, and 5,000 deaths in the United States each year.

The changes that take place in the lungs of asthmatic persons makes the airways (the "breathing tubes," or bronchi and the smaller bronchioles ) hyperreactive to many different types of stimuli that don't affect healthy lungs. In an asthma attack, the muscle tissue in the walls of bronchi go into spasm, and the cells lining the airways swell and secrete mucus into the air spaces. Both these actions cause the bronchi to become narrowed (bronchoconstriction). As a result, an asthmatic person has to make a much greater effort to breathe in air and to expel it.

Cells in the bronchial walls, called mast cells, release certain substances that cause the bronchial muscle to contract and stimulate mucus formation. These substances, which include histamine and a group of chemicals called leukotrienes, also bring white blood cells into the area, which is a key part of the inflammatory response. Many patients with asthma are prone to react to such "foreign" substances as pollen, house dust mites, or animal dander; these are called allergens. On the other hand, asthma affects many patients who are not allergic in this way.

Asthma usually begins in childhood or adolescence, but it also may first appear during adult years. While the symptoms may be similar, certain important aspects of asthma are different in children and adults.

Child-onset asthma

Nearly one-third on the 17 to 26 million Americans with asthma are children. When asthma begins in childhood, it often does so in a child who is likely, for genetic reasons, to become sensitized to common allergens in the environment (atopic person). When these children are exposed to house-dust mites, animal proteins, fungi, or other potential allergens, they produce a type of antibody that is intended to engulf and destroy the foreign materials. This has the effect of making the airway cells sensitive to particular materials. Further exposure can lead rapidly to an asthmatic response. This condition of atopy is present in at least one-third and as many as one-half of the general population. When an infant or young child wheezes during viral infections, the presence of allergy (in the child or a close relative) is a clue that asthma may well continue throughout childhood.

Adult-onset asthma

Allergenic materials may also play a role when adults become asthmatic. Asthma can actually start at any age and in a wide variety of situations. Many adults who are not allergic have conditions such as sinusitis or nasal polyps, or they may be sensitive to aspirin and related drugs. Another major source of adult asthma is exposure at work to animal products, certain forms of plastic, wood dust, or metals.

Causes and symptoms

In most cases, asthma is caused by inhaling an allergen that sets off the chain of biochemical and tissue changes leading to airway inflammation, bronchoconstriction, and wheezing. Because avoiding (or at least minimizing) exposure is the most effective way of treating asthma, it is vital to identify which allergen or irritant is causing symptoms in a particular patient. Once asthma is present, symptoms can be set off or made worse if the patient also has rhinitis (inflammation of the lining of the nose) or sinusitis. When, for some reason, stomach acid passes back up the esophagus (acid reflux), this can also make asthma worse. A viral infection of the respiratory tract can also inflame an asthmatic reaction. Aspirin and a type of drug called beta-blockers, often used to treat high blood pressure, can also worsen the symptoms of asthma.

The most important inhaled allergens giving rise to attacks of asthma are:

  • animal dander
  • mites in house dust
  • fungi (molds) that grow indoors
  • cockroach allergens
  • pollen
  • occupational exposure to chemicals, fumes, or particles of industrial materials in the air

KEY TERMS

Allergen A foreign substance, such as mites in house dust or animal dander which, when inhaled, causes the airways to narrow and produces symptoms of asthma.

Atopy A state that makes persons more likely to develop allergic reactions of any type, including the inflammation and airway narrowing typical of asthma.

Hypersensitivity The state where even a tiny amount of allergen can cause the airways to constrict and bring on an asthmatic attack.

Spirometry A test using an instrument called a spirometer that shows how difficult it is for an asthmatic patient to breathe. Used to determine the severity of asthma and to see how well it is responding to treatment.

Inhaling tobacco smoke, either by smoking or being near people who are smoking, can irritate the airways and trigger an asthmatic attack. Air pollutants can have a similar effect. In addition, there are three important factors that regularly produce attacks in certain asthmatic patients, and they may sometimes be the sole cause of symptoms. They are:

  • inhaling cold air (cold-induced asthma)
  • exercise-induced asthma (in certain children, asthma is caused simply by exercising)
  • stress or a high level of anxiety

Wheezing is often obvious, but mild asthmatic attacks may be confirmed when the physician listens to the patient's chest with a stethoscope. Besides wheezing and being short of breath, the patient may cough and may report a feeling of "tightness" in the chest. Children may have itching on their back or neck at the start of an attack. Wheezing is often loudest when the patient breathes out, in an attempt to expel used air through the narrowed airways. Some asthmatics are free of symptoms most of the time but may occasionally be short of breath for a brief time. Others spend much of their days (and nights) coughing and wheezing, until properly treated. Crying or even laughing may bring on an attack. Severe episodes are often seen when the patient gets a viral respiratory tract infection or is exposed to a heavy load of an allergen or irritant. Asthmatic attacks may last only a few minutes or can go on for hours or even days (a condition called status asthmaticus).

Being short of breath may cause a patient to become very anxious, sit upright, lean forward, and use the muscles of the neck and chest wall to help breathe. The patient may be able to say only a few words at a time before stopping to take a breath. Confusion and a bluish tint to the skin are clues that the oxygen supply is much too low, and that emergency treatment is needed. In a severe attack that lasts for some time, some of the air sacs in the lung may rupture so that air collects within the chest. This makes it even harder to breathe in enough air.

Diagnosis

Apart from listening to the patient's chest, the examiner should look for maximum chest expansion while taking in air. Hunched shoulders and contracting neck muscles are other signs of narrowed airways. Nasal polyps or increased amounts of nasal secretions are often noted in asthmatic patients. Skin changes, like atopic dermatitis or eczema, are a tipoff that the patient has allergic problems.

Inquiring about a family history of asthma or allergies can be a valuable indicator of asthma. The diagnosis may be strongly suggested when typical symptoms and signs are present. A test called spirometry measures how rapidly air is exhaled and how much is retained in the lungs. Repeating the test after the patient inhales a drug that widens the air passages (a bronchodilator) will show whether the airway narrowing is reversible, which is a very typical finding in asthma. Often patients use a related instrument, called a peak flow meter, to keep track of asthma severity when at home.

Often, it is difficult to determine what is triggering asthma attacks. Allergy skin testing may be used, although an allergic skin response does not always mean that the allergen being tested is causing the asthma. Also, the body's immune system produces antibody to fight off the allergen, and the amount of antibody can be measured by a blood test. This will show how sensitive the patient is to a particular allergen. If the diagnosis is still in doubt, the patient can inhale a suspect allergen while using a spirometer to detect airway narrowing. Spirometry can also be repeated after a bout of exercise if exercise-induced asthma is a possibility. A chest x ray will help rule out other disorders.

Treatment

Patients should be periodically examined and have their lung function measured by spirometry to make sure that treatment goals are being met. These goals are to prevent troublesome symptoms, to maintain lung function as close to normal as possible, and to allow patients to pursue their normal activities including those requiring exertion. The best drug therapy is that which controls asthmatic symptoms while causing few or no side-effects.

Drugs

METHYLXANTHINES. The chief methylxanthine drug is theophylline. It may exert some anti-inflammatory effect, and is especially helpful in controlling nighttime symptoms of asthma. When, for some reason, a patient cannot use an inhaler to maintain long-term control, sustained-release theophylline is a good alternative. The blood levels of the drug must be measured periodically, as too high a dose can cause an abnormal heart rhythm or convulsions.

BETA-RECEPTOR AGONISTS. These drugs, which are bronchodilators, are the best choice for relieving sudden attacks of asthma and for preventing attacks from being triggered by exercise. Some agonists, such as albuterol, act mainly in lung cells and have little effect on other organs, such as the heart. These drugs generally start acting within minutes, but their effects last only four to six hours. Longer-acting brochodilators have been developed. They may last up to 12 hours. Bronchodilators may be taken in pill or liquid form, but normally are used as inhalers, which go directly to the lungs and result in fewer side effects.

STEROIDS. These drugs, which resemble natural body hormones, block inflammation and are extremely effective in relieving symptoms of asthma. When steroids are taken by inhalation for a long period, asthma attacks become less frequent as the airways become less sensitive to allergens. This is the strongest medicine for asthma, and can control even severe cases over the long term and maintain good lung function. Steroids can cause numerous side-effects, however, including bleeding from the stomach, loss of calcium from bones, cataracts in the eye, and a diabetes-like state. Patients using steroids for lengthy periods may also have problems with wound healing, may gain weight, and may suffer mental problems. In children, growth may be slowed. Besides being inhaled, steroids may be taken by mouth or injected, to rapidly control severe asthma.

LEUKOTRIENE MODIFIERS. Leukotriene modifiers (montelukast and zafirlukast) are a new type of drug that can be used in place of steroids, for older children or adults who have a mild degree of asthma that persists. They work by counteracting leukotrienes, which are substances released by white blood cells in the lung that cause the air passages to constrict and promote mucus secretion. Leukotriene modifiers also fight off some forms of rhinitis, an added bonus for people with asthma. However, they are not proven effective in fighting seasonal allergies.

OTHER DRUGS. Cromolyn and nedocromil are anti-inflammatory drugs that are often used as initial treatment to prevent asthmatic attacks over the long term in children. They can also prevent attacks when given before exercise or when exposure to an allergen cannot be avoided. These are safe drugs but are expensive, and must be taken regularly even if there are no symptoms. Anti-cholinergic drugs, such as atropine, are useful in controlling severe attacks when added to an inhaled beta-receptor agonist. They help widen the airways and suppress mucus production.

If a patient's asthma is caused by an allergen that cannot be avoided and it has been difficult to control symptoms by drugs, immunotherapy may be worth trying. Typically, increasing amounts of the allergen are injected over a period of three to five years, so that the body can build up an effective immune response. There is a risk that this treatment may itself cause the airways to become narrowed and bring on an asthmatic attack. Not all experts are enthusiastic about immunotherapy, although some studies have shown that it reduces asthmatic symptoms caused by exposure to house-dust mites, ragweed pollen, and cat dander.

Managing asthmatic attacks

A severe asthma attack should be treated as quickly as possible. It is most important for a patient suffering an acute attack to be given extra oxygen. Rarely, it may be necessary to use a mechanical ventilator to help the patient breathe. A beta-receptor agonist is inhaled repeatedly or continuously. If the patient does not respond promptly and completely, a steroid is given. A course of steroid therapy, given after the attack is over, will make a recurrence less likely.

Maintaining control

Long-term asthma treatment is based on inhaling a beta-receptor agonist using a special inhaler that meters the dose. Patients must be instructed in proper use of an inhaler to be sure that it will deliver the right amount of drug. Once asthma has been controlled for several weeks or months, it is worth trying to cut down on drug treatment, but this must be done gradually. The last drug added should be the first to be reduced. Patients should be seen every one to six months, depending on the frequency of attacks.

Starting treatment at home, rather than in a hospital, makes for minimal delay and helps the patient to gain a sense of control over the disease. All patients should be taught how to monitor their symptoms so that they will know when an attack is starting, and those with moderate or severe asthma should know how to use a flow meter. They should also have a written "action plan" to follow if symptoms suddenly become worse, including how to adjust their medication and when to seek medical help. A 2004 report said that a review of medical studies revealed that patients with self-management written action plans had fewer hospitalizations, fewer emergency department visits, and improved lung function. They also had a 70% lower mortality rate. If more intense treatment is necessary, it should be continued for several days. Over-the-counter "remedies" should be avoided. When deciding whether a patient should be hospitalized, the past history of acute attacks, severity of symptoms, current medication, and whether good support is available at home all must be taken into account.

Referral to an asthma specialist should be considered if:

  • there has been a life-threatening asthma attack or severe, persistent asthma
  • treatment for three to six months has not met its goals
  • some other condition, such as nasal polyps or chronic lung disease, is complicating asthma
  • special tests, such as allergy skin testing or an allergen challenge, are needed
  • intensive steroid therapy has been necessary

Special populations

INFANTS AND YOUNG CHILDREN. It is especially important to closely watch the course of asthma in young patients. Treatment is cut down when possible and if there is no clear improvement, some other treatment should be tried. If a viral infection leads to severe asthmatic symptoms, steroids may help. The health care provider should write out an asthma treatment plan for the child's school. Asthmatic children often need medication at school to control acute symptoms or to prevent exercise-induced attacks. Proper management will usually allow a child to take part in play activities. Only as a last resort should activities be limited.

THE ELDERLY. Older persons often have other types of obstructive lung disease, such as chronic bronchitis or emphysema. This makes it important to know to what extent the symptoms are caused by asthma. Giving steroids for two to three weeks can help determine this. Side-effects from beta-receptor agonist drugs (including a speeding heart and tremor) may be more common in older patients. These patients may benefit from receiving an anti-cholinergic drug, along with the beta-receptor agonist. If theophylline is given, the dose should be limited, as older patients are less able to clear this drug from their blood. Steroids should be avoided, as they often make elderly patients confused and agitated. Steroids may also further weaken the bones.

Prognosis

Most patients with asthma respond well when the best drug or combination of drugs is found, and they are able to lead relatively normal lives. More than one-half of affected children stop having attacks by the time they reach 21 years of age. Many others have less frequent and less severe attacks as they grow older. Urgent measures to control asthma attacks and ongoing treatment to prevent attacks are equally important. A small minority of patients will have progressively more trouble breathing and run a risk of going into respiratory failure, for which they must receive intensive treatment.

Prevention

Minimizing exposure to allergens

There are a number of ways to cut down exposure to the common allergens and irritants that provoke asthmatic attacks, or to avoid them altogether:

  • If the patient is sensitive to a family pet, removing the animal or at least keeping it out of the bedroom (with the bedroom door closed), as well as keeping the pet away from carpets and upholstered furniture and Removing hair and feathers.
  • To reduce exposure to house dust mites, removing wall-to-wall carpeting, keeping humidity down, and using special pillows and mattress covers. Cutting down on stuffed toys, and washing them each week in hot water.
  • If cockroach allergen is causing asthma attacks, killing the roaches (using poison, traps, or boric acid rather than chemicals). Taking care not to leave food or garbage exposed.
  • Keeping indoor air clean by vacuuming carpets once or twice a week (with the patient absent), avoiding using humidifiers. Using air conditioning during warm weather (so that the windows can be closed).
  • Avoiding exposure to tobacco smoke.
  • Not exercising outside when air pollution levels are high.
  • When asthma is related to exposure at work, taking all precautions, including wearing a mask and, if necessary, arranging to work in a safer area.

More than 80% of people with asthma have rhinitis and recent research emphasizes that treating rhinitis helps benefit ashtma. Prescription nasal steroids and other methods to control rhinitis (in addition to avoiding known allergens) can help prevent asthma attacks. It is also important for patients to keep open communication with physicians to ensure that the correcnt amount of medication is being taken.

Resources

PERIODICALS

"Many People With Asthma ArenÆt Taking the Right Amount of Medication." Obesity, Fitness & Wellness Week (September 25, 2004): 87.

Mintz, Matthew. "Asthma Update: Part 1. Diagnosis, Monitoring, and Prevention of Disease Progression." American Family Physician September 1, 2004: 893.

Solomon, Gina, Elizabeth H. Humphreys, and Mark D. Miller. "Asthma and the Environment: Connecting the Dots: What Role do Environmental Exposures Play in the Rising Prevalence and Severity of Asthma?" Contemporary Peditatrics August 2004: 73-81.

"WhatÆs New in: Asthma and Allergic Rhinitis." Pulse September 20, 2004: 50.

ORGANIZATIONS

Asthma and Allergy Foundation of America. 1233 20th Street, NW, Suite 402, Washington, DC 20036. (800) 727-8462. http://www.aafa.org.

Mothers of Asthmatics, Inc. 3554 Chain Bridge Road, Suite 200, Fairfax, VA 22030. (800) 878-4403.

National Asthma Education Program. 4733 Bethesda Ave., Suite 350, Bethesda, MD 20814. (301) 495-4484.

National Jewish Medical and Research Center. 1400 Jackson St., Denver, CO 80206. (800) 222-LUNG.

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Asthma

ASTHMA

Asthma is a common chronic lung disease characterized by a narrowing of the airways, resulting in obstruction of the flow of air and difficulty in breathing. The airflow obstruction is partially or completely reversible in most patients. Different designations of asthma include bronchial asthma, exercise-induced asthma, drug-induced asthma, occupational asthma, and cardiac asthma (airway narrowing in the setting of congestive heart failure). This discussion focuses primarily on bronchial asthma, a chronic inflammatory disorder of the airways (both the larger "bronchi" and the smaller "bronchioles"), resulting in airflow obstruction and increased sensitivity (responsiveness) of the airways to a variety of stimuli ("bronchial hyperreactivity").

About 15 million Americans, a third of whom are children, suffer from asthma, and more than 5,000 people die from it each year. The condition accounts for an estimated 100 million days of restricted activity and 470,000 hospitalizations annually in the United States. Over the last three to four decades both the prevalence and the death rate from asthma in the United States and many other developed countries have increased. In the United States, the increases in death rates have been higher in women than in men and higher in blacks than in whites.

The most important risk factor to develop bronchial asthma is atopy, an inherited predisposition to have allergies. An acute attack of asthma may occur if an atopic individual inhales allergy-provoking substances (allergens) such as ragweed, cat dander, or house dust. A variety of cells are involved in the asthmatic inflammatory reaction in the airway walls, including neutrophils, eosinophils, lymphocytes, mast cells, and macrophages. These cells release mediators (chemicals such as "cytokines") that provoke the inflammatory process. Asthma also occurs in people without allergies.

During an acute episode of asthma, bronchial narrowing ("bronchoconstriction") results from the buildup of plugs of mucus and cellular debris in the lumen, contraction of smooth-muscle cells ringing the airways, and inflammation and edema of the mucosa. Permanent changes in the airway, including enlargement of the submucosal mucous glands, proliferation of mucus-secreting cells and smooth-muscle cells, and deposition of fibrous tissue in the mucosa, may occur in chronic asthma, a process known as "airway remodeling."

The degree of airflow limitation in patients with asthma is measured by performing breathing tests (pulmonary function tests) such as spirometry and the recording of peak expiratory flow rates (PEFRs). This requires the patient to take in as deep a breath as possible and blow it out with maximum effort into a recording instrument. Obstructive dysfunction is detected if airflow rates are significantly less than predicted values. Partial or complete reversibility of the obstructive dysfunction is possible in most cases after the inhalation of a medication (e.g., albuterol) that dilates the airways. Between episodes of asthma, airflow rates may be normal. However, a patient who has had asthma for many years may display persistent and irreversible obstructive dysfunction as a result of airway remodeling. Spirometry is also employed in bronchial-provocation testing to determine if an individual with suspected asthma has bronchial hyperreactivity (an unusual degree of airway sensitivity to challenges such as exercise or the inhalation of dilute solutions of chemicals such as methacholine).

Patients with asthma suffer from shortness of breath, wheezing, chest tightness, and cough. These symptoms, which may be episodic or chronic, are often worse early in the morning and may disrupt sleep. Asthma often develops in childhood, but it may appear at any age. Episodes of asthma may be spontaneous, but more commonly they are "triggered" by various stimuli, such as inhaling allergens or nonspecific airway irritants (e.g., dusts, smoke, fumes, cold air), upper or lower respiratory tract infections, exercise, certain medications, and exposure to chemicals and other substances in the workplace. The frequency and severity of symptoms vary greatly from patient to patient and tend to be less episodic and more persistent with increasing age.

The diagnosis of bronchial asthma depends upon a medical history of one or more asthma symptoms, evidence of airflow limitation on physical examination or pulmonary function testing, and demonstration of some degree of reversibility of airflow obstruction. Other conditions that mimic asthma must be excluded. These include acute or chronic bronchitis, emphysema, bronchiectasis, cystic fibrosis, upper airway obstruction from various causes, abnormal function of the vocal cords, aspiration, lung cancer, congestive heart failure, pulmonary thromboembolism (blood clots in the pulmonary artery), and even certain psychiatric disorders.

Asthma is classified according to the severity and frequency of its symptoms and the results of pulmonary function tests. Mild intermittent asthma is managed by treating the occasional symptoms with inhaled bronchodilators, called beta2-agonists. Persistent asthma is treated with daily anti-inflammatory drugs, especially inhaled corticosteroids, often in combination with one or more inhaled or oral bronchodilator drugs. A newer class of drugs called leukotriene modifiers is employed to manage some patients with persistent asthma. Severe persistent asthma requires the daily use of several medications, including oral corticosteroids such as prednisone. Acute, severe asthma may require the patient to be hospitalized to manage acute respiratory failure with supplemental oxygen and even respiratory support on a mechanical ventilator.

Patient education, environmental control, smoking cessation, and avoidance of factors known to provoke attacks are the mainstays of prevention. The importance of stopping smoking cannot be overemphasized. Patients with asthma must reduce exposure to allergens (such as house dust mites and animal danders), eliminate certain medications (such as beta-blocker drugs and aspirin), and avoid exposure to indoor and outdoor air pollutants. A diagnosis of occupational asthma requires that steps be taken to curtail workplace exposure to offending agents. Annual vaccination against influenza virus infection is recommended for patients with persistent asthma.

Fortunately, most patients with asthma respond well to appropriate medical management. Anti-inflammatory therapy for persistent asthma and immediate treatment for acute, severe attacks are essential steps to reduce morbidity and mortality from the disease. Death from bronchial asthma is considered to be preventable.

John L. Stauffer

(see also: Chronic Respiratory Diseases; Emphysema; Pulmonary Function )

Bibliography

"Drugs for Asthma." The Medical Letter on Drugs and Therapeutics 41(2000):1924.

McFadden, E. R., Jr. (1998) "Asthma." In Harrison's Principles of Internal Medicine, 14th edition, ed. A. S. Fauci et al. New York: McGraw-Hill.

McFadden, E. R., Jr., and Warren E. L. (1997). "Observations on Asthma Mortality." Annual of Internal Medicine 127:142147.

National Asthma Education Program (1997). "Expert Panel Report 2: Guidelines for the Diagnosis and Management of Asthma." Bethesda, MD: National Heart, Lung, and Blood Institute. Available at http://www.nhlbi.nih.gov/nhlbi/lung/asthma/prof/asthgdln.htm.

Woolcock, A. J., and Barnes, P. J. (2000). "Asthma: The Important Questions. Part 4." American Journal of Respiratory and Critical Care Medicine 161(3):S157 S217.

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Asthma

Asthma


Asthma is a chronic disease of the lungs that affects millions around the world, particularly in industrialized countries. The symptoms of asthma include shortness of breath, chest tightness, wheezing, and coughing; nighttime symptoms that interfere with sleep can be particularly troublesome. These symptoms are caused by inflammation, swelling, and constriction of muscles that surround the breathing tubes in the chest, the airways connecting the lungs to the mouth and nose. The hallmark of asthma is variability and reversibility in the inflammation and constriction of the airways.

Although researchers have identified a number of chemicals in the workplace that can cause asthma, the cause of most cases of asthma is unknown. Genetic risk factors are important; adults who have asthma are more likely to produce children with asthma than adults who do not suffer from this ailment. Genetic risk cannot explain the increase in the number of persons with asthma in the United States, from 6.8 million persons in 1980 to about 15 million in 1996, because the genetic composition of the population changes much more slowly than that.

Whether outdoor air pollution might cause asthma has not been sufficiently studied. Although many people are afflicted with asthma, determining exactly when an individual's disease beganso the critical period of environmental exposures might be identifiedis difficult. Studies comparing the overall rate of asthma with air pollution levels have not produced data showing a relationship between asthma and outdoor pollution. For example, increases in the number of persons with asthma in the United States occurred while the overall levels of outdoor air pollution were declining. Despite the overall decline in air pollution, concentrations of ozone and airborne particles with a diameter less than 10 microns (abbreviated as PM10) have hardly declined at all. Nevertheless, these trends do not implicate outdoor air pollution as an important cause of the increase in asthma sufferers. Information comparing rates of asthma among children born in Germany before and after reunification in 1989 also do not support a role for air pollution in causing asthma. Air pollution from industrial sources was greater in the former East Germany than in West Germany, yet the situation with asthma was the reverse, with a higher rate of asthma present in West Germany. The difference in asthma rates appeared to result from higher rates of allergy in West Germany. In contrast to these studies, one recent study conducted in southern California found an increased risk for developing asthma in children who participated in team sports, a surrogate for greater exposure, and who also lived in areas with higher ozone levels.

Some outdoor air pollutants, such as ground-level ozone, PM10, sulfur dioxide, and nitrogen oxides, can worsen asthma. Related studies compare the rate of emergency department visits for asthma at times of high levels of air pollution with such visits at times of low levels of air pollution. In a study conducted during the 1996 Olympics in Atlanta, changes in traffic patterns were associated with reduced levels of ozone and with fewer emergency department visits for asthma.

Indoor air pollution probably plays a more significant role in asthma than outdoor air pollution. On average, people spend much more time indoors than outdoors, and concentrations of some pollutants can be many times higher indoors. Indoor air exposures are classified as being biological, derived from living organisms, or chemical. Because no regulations exist for levels of indoor air pollutants, concentrations of these exposures are not measured with the same frequency and uniformity as those for outdoor pollutants.

Among indoor exposures, exposure to house dust mites has been found to cause asthma and, for preschool-aged children, environmental tobacco smoke has been associated with the development of asthma. Some evidence exists that exposure to cockroaches and infection with respiratory syncytial virus also may be linked to the development of asthma. Researchers have correspondingly identified a much longer list of indoor exposures that can trigger or worsen asthma: besides the above factors, exposure to cat dander, molds, dogs, and nitrogen oxides.

An individual can take many steps to reduce exposure to the factors that exacerbate asthma. Basic precautions include the following: Stop smoking and avoid tobacco smoke; vacuum the home once or twice a week (but with the asthma-affected person not present); avoid mold, making sure that moisture collections are addressed to prevent mold growth; and reduce exposure to house dust mites, cats, dogs, and cockroaches, depending on which of these are allergic triggers for the asthma sufferer.

The importance of air pollution, whether indoor or outdoor, as a cause of asthma remains a subject of intense study. Exposure to house dust mites appears to be capable of causing asthma and environmental tobacco smoke has been associated with the development of asthma, but evidence linking these exposures to the increase in asthma cases is lacking.

see also Air Pollution; Health, Human; Indoor Air Pollution.

Bibliography

Committee on the Assessment of Asthma and Indoor Air. (2000). Clearing the Air: Asthma and Indoor Air Exposures. Washington, DC: National Academy Press.

Pearce, Neal; Beasley, Richard; Burgess, Carl; and Crane, Julian, eds. (1998). Asthma Epidemiology: Principles and Methods. New York: Oxford University Press.

Internet Resource

National Asthma Education and Prevention Program. (1997). Facts about Controlling Your Asthma. Bethesda, MD: Public Health Service. Available from http://www.nhlbi.nih.gov/health.

Stephen C. Redd

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Asthma

Asthma

Asthma is a reversible lung disease that affects approximately four million people in the United States. It is sometimes referred to as a disease of twitchy or reactive lungs, which means that the airways of the lungs are extremely sensitive to irritants such as pollen, animal dander (hair, feathers, or skin), dust, or tobacco smoke. When these irritants are inhaled, the airways react by constricting or narrowing. In some people, asthma attacks follow a cold or a severe respiratory infection. Stress, exercise, and even changes in temperature or humidity can bring on attacks of asthma, as can certain drugs such as aspirin.

Some people with asthma have only mild symptoms that occur from time to time. Others have symptoms that occur frequently and that can be mild, moderate, or severe in nature. Severe asthma attacks are sometimes life threatening. Although researchers have learned more about the underlying causes of asthma in recent years, there is no specific treatment for the disease. In fact, deaths from asthma are on the rise. Many experts believe that lack of standard treatments and inconsistent monitoring of asthma patients have contributed to this increased rate of death.

How asthma affects the airways

The airways are tubes called bronchi that branch into smaller tubes called bronchioles. They carry air from the windpipe to the lungs. During an asthma attack, the airways are narrowed due to muscle spasms, swelling and inflammation of the airway walls, and the production of large amounts of mucus. This results in a blocking of the passage of air to the lungs. The characteristic sign of asthma is wheezing, the noisy whistling sound that a person makes as he or she tries to push air in and out of narrowed airways. Other symptoms include the sensation of a tight chest, shortness of breath (breathlessness), and a cough.

Treatment of asthma

Treatment of asthma aims at opening the airways and reducing inflammation. There are two general categories of medications used to treat the disease: those that bring quick relief in the sudden onset of an asthma attack and those used long-term to control persistent asthma. The treatment used may vary from patient to patient, based on individual need. While an inhaler may be used occasionally in very mild cases, often a combination of drugs is prescribed for moderate to severe forms. Extremely severe, or acute, attacks of asthma may require the patient to be hospitalized.

Words to Know

Bronchi: The two main airway tubes that branch off from the windpipe and lead to each lung.

Bronchiole: Any of the smaller airway tubes that branch off from the bronchi.

Bronchodilator: A drug, either inhaled or taken orally, that widens the lung airways by relaxing the smooth muscles of the airways.

Constriction: In asthma, the characteristic narrowing of the airways.

Bronchodilators are drugs that dilate, or widen, constricted lung airways by relaxing the smooth muscles of the airways. They can either be inhaled through a special device or taken orally (by mouth) in pill form. Inhaled bronchodilators are usually prescribed for mild to moderate forms of asthma. Because they are applied directly to the constricted airways, they act quickly; the patient is instructed to inhale the drug as soon as he or she feels an attack coming on. Oral bronchodilators are longer acting and are usually prescribed for severe asthma. A new, longer-acting bronchodilator called Salmeterol, which is inhaled, combines the direct effects of inhaled bronchodilators with the long-lasting protection of oral ones. It is useful in maintaining clear airways and in preventing nighttime flare-ups of asthma, as well as those caused by such stimuli as exercise and changes in temperature.

The inflammation associated with asthma has a direct effect on lung function. Increased emphasis has been placed on the use of anti-inflammatory drugs to reduce swelling and inflammation of the airways. In cases of persistent asthma, it is often recommended that anti-inflammatory medications, such as corticosteroids (pronounced kor-tik-oh-STEH-roydz), be taken on a daily basis. They can either be inhaled or taken in pill form.

Another medication commonly used in the treatment of asthma is Cromolyn, a drug that blocks the release of histamine. Histamine is a chemical that the body produces in response to allergy-causing substances. Its release prompts constriction of the airways, which results in difficulty

breathing. Cromolyn is used to prevent asthma attacks rather than as a treatment during attacks.

Managing asthma and preventing attacks

The key to managing asthma and preventing attacks is the patient's ability to recognize the factors that trigger an attackand then making the conscious effort to avoid them. Since allergies and asthma often go hand in hand, allergy testing may be an effective way to identify allergens (allergy-causing substances) in some patients. If asthma is brought on by exercise, finding a level of exertion that is comfortable or using an inhaled bronchodilator before exercise may help to control symptoms. Taking medicine as prescribed is also an important factor in maintaining control of the disease.

For all persons with asthma, the most important aspect of managing their disease is communication with and regular visits to their physician. It is essential that patient and physician work together to monitor progress and keep abreast of any changes in the patient's condition.

[See also Respiratory system ]

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Asthma

ASTHMA

Due to its frequent association with psychoaffective symptoms, asthma is considered a classic psychosomatic disorder. The Hungarian-American analyst Franz Alexander was an early proponent of psychosomatic medicine, and during the 1940s he and Thomas French applied the "specific emotion theory" to try to establish a link between the onset of asthmatic attacks and emotional conflicts. Their research suggested that pregenital instinctual desires, experienced as threatening to the dependent mother-child dyad, could give rise to bronchial symptoms, noting that breathing is the first independent post-natal physiological function. It is possible to view the infant's double separation from the motherbiological and psycho-affectiveas reviving the Freud-Rank birth trauma debate. A generation later in 1963, research by Peter Hobart Knapp suggested that allergic diathesis was a necessary precondition to developing symptoms, and offered as possible triggering mechanisms either hysterical conversion or conflicts of oral incorporation expressed through the respiratory apparatus.

In France, Pierre Marty, one of the founders of the Ecole de Psychosomatique de Paris, theorized that asthma, like other allergic manifestations, arises from a specific type of object relationship that involves a form of profound and almost instantaneous mimetic identification that includes a projective movement identifying object with subject. The difficulty of maintaining such a state of confused fusion either produces some accommodation or, in the case of an intractable object, creates a distance from the object that may be considered at once symbolic and real. The separation from the object whose own characteristics are too distant from, or independent of, the subject, occurs without the work of mourning. The asthmatic attack breaks out during conflict between two objects, both equally invested but themselves in conflict. The asthmatic attack externalizes and diverts internal psychological destruction.

Robert AssÉo

See also: Allergy; Psychosomatic.

Bibliography

Alexander, Franz, and French, Thomas M. (1941). Psychogenic factors in bronchial asthma. Washington, DC: National Research Council.

Bauduin, Andrée. (1985). L'asthme bronchique, aspects dynamiques et psychanalytiques. Revue médicale de Liège, 90 (22).

Fenichel, Otto. (1953). The collected papers of Otto Fenichel. First and second series (H. Fenichel and D. Rapaport, Eds.). New York: Norton.

Knapp, Peter H. (1989). Psychosomatic aspects of bronchial asthma. Madison, CT: International Universities Press.

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asthma

asthma (ăz´mə, ăs´–), chronic inflammatory respiratory disease characterized by periodic attacks of wheezing, shortness of breath, and a tight feeling in the chest. A cough producing sticky mucus is symptomatic. The symptoms often appear to be caused by the body's reaction to a trigger such as an allergen (commonly pollen, house dust, animal dander: see allergy), certain drugs, an irritant (such as cigarette smoke or workplace chemicals), exercise, or emotional stress. These triggers can cause the asthmatic's lungs to release chemicals that create inflammation of the bronchial lining, constriction, and bronchial spasms. If the effect on the bronchi becomes severe enough to impede exhalation, carbon dioxide can build up in the lungs and lead to unconsciousness and death. Following a steady 30-year decline, asthma deaths in the United States, especially among poor, inner-city blacks and among the elderly, began to rise from the late 1970s through the early 1990s. At the same time, the incidence of asthma also increased, both nationally and worldwide.

There is no cure for asthma. Although the disease may go through a period of quiescence, it appears that childhood asthmatics do not outgrow the disease as previously believed. Treatment includes inhaled or oral steroids or bronchodilators (albuterol, theophylline), breathing exercises, and, if possible, the identification and avoidance of triggers.

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asthma

asthma (ass-mă) n. the condition of subjects with widespread narrowing of the bronchial airways, which changes in severity over short periods of time and leads to coughing, wheezing, and difficulty in breathing. bronchial a. asthma that may be precipitated by exposure to one or more of a wide range of stimuli, including allergens, drugs (such as aspirin), exertion, emotion, infections, and air pollution. Treatment is with bronchodilators, with or without corticosteroids, usually administered via aerosol or dry-powder inhalers, or – if the condition is more severe – via a nebulizer. Severe asthmatic attacks may need large doses or oral corticosteroids (see status asthmaticus). cardiac a. asthma that occurs in left ventricular heart failure and must be distinguished from bronchial asthma, as the treatment is quite different.
asthmatic (ass-mat-ik) adj.

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Asthma

ASTHMA

DEFINITION


Asthma (pronounced AZ-muh) is a chronic (long-lasting) inflammatory disease of the airways in the human body. The inflammation causes the airways to narrow from time to time. This narrowing can produce wheezing and breathlessness. In extreme cases, the asthma patient may need to gasp to get enough air to breathe. Occasionally, a severe asthma attack can be fatal.

This condition sometimes improves on its own. In other cases, medication is needed to reopen airways. When inflammation occurs over and over again, the airways become especially sensitive to certain environmental conditions, such as cold air, dust mites, and pollen in the air. Exercise, stress, and anxiety can produce similar effects.

DESCRIPTION


About ten million Americans have asthma, and the number seems to be increasing. Between 1982 and 1992, the rate rose by 42 percent. Asthma is also becoming a more serious disease. In the same 10-year period, the death rate from asthma in the United States increased by 35 percent. These changes have come about in spite of new and improved drugs for the treatment of asthma.

An asthma attack affects the bronchi (pronounced BRONG-ki) and bronchioles (pronounced BRONG-kee-olz) in the lungs. The bronchi and bronchioles are tiny tubes through which air passes in and out of the body. In people with asthma, certain materials, such as dust and pollen, can irritate these tubes. By contrast, people without asthma are unaffected by these materials.

As these tubes become irritated, they swell and give off mucus, a sticky liquid. The liquid fills air spaces in the bronchi and bronchioles. Both swelling and mucus narrow the tubes, making it more difficult for air to get in and out of the lungs. As a result, an asthmatic person has to make a much greater effort to breathe in air and to expel it.

Asthma usually begins in childhood or adolescence, however it may first appear during the adult years. While the symptoms may be similar for these two cases, certain aspects of asthma are different in children and adults.

Child-onset Asthma

Some children are thought to develop asthma for genetic reasons. Their bodies are especially sensitive to materials in the environment that have little or no effect on other people. These materials are known as allergens (pronounced AL-erjins) because they produce an allergic response.

Asthma: Words to Know

Allergen:
A foreign substance which, when inhaled, causes the airways to narrow and produces the symptoms of asthma.
Atopy:
A condition in which people are more likely to develop allergic reactions, often because of the inflammation and airway narrowing typical of asthma.
Spirometer:
An instrument that shows how much air a patient is able to exhale and hold in his or her lungs as a test to see how serious a person's asthma is and how well he or she is responding to treatment.

When children with this condition are exposed to dust mites, fungi, and other allergens, their bodies produce chemicals known as antibodies. The function of these antibodies is to fight off the invasion of materials from the environment. However, the release of antibodies also inflames the bronchi and bronchioles. The more often an asthmatic child is exposed to allergens, the more serious the response becomes. This condition, known as atopy (pronounced A-tuh-pee), is thought to occur in anywhere from 30 to 50 percent of the general population.

Adult-onset Asthma

Some individuals do not exhibit the symptoms of asthma until their adult years. In some cases, the cause of the disease may be the same as they are for children. In other cases, asthma is thought to be a result of exposure to wood dust, metals, certain forms of plastic, or other materials that get into the air in the workplace or at home.

CAUSES


In most cases, asthma is caused by inhaling an allergen. That allergen then sets off a series of reactions in the body that cause inflammation of bronchi and bronchioles. The most common inhaled allergens that lead to asthma attacks are:

  • Animal dander (dry skin that is shed)
  • Chemicals, fumes, or tiny particles that occur in the air in workplaces
  • Fungi (molds) that grow indoors
  • Mites found in house dust
  • Pollen

Tobacco smoke is another cause of asthma attacks. The smoke irritates bronchi and bronchioles, setting off an asthma reaction. The same effect is caused whether an individual himself is smoking or is inhaling smoke second-hand (from someone else). Air pollutants can have a similar effect.

Three other factors can produce asthma attacks. They are:

  • Exercise (exercise-related asthma)
  • Inhaling cold air (cold-induced asthma)
  • Stress or anxiety

Other factors that can cause an asthma attack or make it worse are rhinitis (pronounced ri-NIE-tuss; inflammation of the nose), sinusitis (pronounced sie-nuh-SIE-tis; inflammation of the sinuses), acid reflux (known as acid stomach), and viral infections of the respiratory (breathing) system.

SYMPTOMS


Wheezing is the most obvious symptom of an asthma attack. In most cases, the wheezing is loud and easy to observe. In other cases, it may be soft and hard to hear. A doctor may be able to hear the wheezing only by listening to the patient's chest with a stethoscope. Coughing and tightness in

the chest are other symptoms of asthma. Children sometimes complain of an itchiness on their back or neck at the start of an asthma attack.

A number of other outward signs are associated with an asthma attack. An attack may cause a person to become very anxious. He or she may sit upright, lean forward, or take some other position to make breathing easier. The person may be able to say only a few words before stopping to take a breath.

An attack may cause a person to become confused or may cause his or her skin to turn blue. Confusion and a blue skin color are signs that the person's body is not getting enough oxygen. The person should be given emergency treatment immediately. In the most severe cases, air sacs in the lungs may rupture. This causes air to collect in the chest, making it even more difficult for the person to breathe.

Some asthmatics may be free of symptoms most of the time. They may experience shortness of breath only on rare occasions and for short periods. Other asthmatics are in discomfort much of the time, coughing, wheezing, and trying to breathe normally. In some cases, crying or laughing can bring on an asthma attack.

The most serious attack can occur when a person already has an infection of the respiratory tract. High doses of an allergen can also trigger major attacks. Asthmatic attacks vary in their length as well as seriousness. Some attacks last only a few minutes. Others go on for hours or even days. Except in the most severe cases, patients recover from even the most serious asthma attacks.

DIAGNOSIS


A first step in diagnosis often involves taking a personal and family medical history. These histories can help a doctor determine whether asthma is a likely cause of a patient's problems.

Visual signs can also be used to diagnose asthma. Hunched shoulders and tightened neck muscles indicate that a patient is trying to get more air into his or her lungs. Increased amounts of nasal (nose) secretions are another sign of asthma. Eczema (pronounced EK-suh-muh) and other skin disorders (see skin disorders entry) are a sign that a person may have allergic reactions associated with asthma.

A number of tests can be used to diagnose asthma. A spirometer, for example, measures the rate at which air is exhaled from the lungs and how much air remains in the lungs. The device is used before and after a patient inhales a drug that widens the air passages. It tells whether airway narrowing is reversible, a typical finding with asthma. Patients can be given a similar instrument called a peak flow meter to use at home. The instrument helps them to determine how serious an asthma attack is.

Tests can also be used to determine the conditions that trigger an asthma attack. Skin tests may show any allergens to which a person is sensitive. That allergen may or may not, however, also be the cause of asthma attacks. Blood tests for the presence of antibodies can also be performed. Any antibodies found in the blood may indicate the allergens to which a person is sensitive.

Patients can also be asked to inhale specific allergens to see what effects they have. A spirometer is used to determine whether airways have become narrowed by the allergen. The spirometer is also used after a patient has exercised to see whether exercise-induced asthma is a possibility. A chest X ray can be taken to rule out conditions that produce symptoms similar to those of asthma.

TREATMENT


There are three primary goals of an asthma treatment program. First, troublesome symptoms should be prevented to the greatest extent possible. Second, lung function should be kept as close to normal as possible. Third, patients should be able to carry out their normal activities, including those requiring special effort, such as vigorous exercise. Patients should be examined on a regular basis to make sure treatment goals are being met. Spirometer tests are an essential part of these examinations.

Drugs

The goal of drug therapy is to find medications that control the symptoms of asthma with few or no side effects.

METHYLXANTHINES. The most commonly used methylxanthine (pronounced meth-uhl-ZAN-theen) is theophylline (pronounced thee-OFF-uh-lin).

Theophylline is used to reduce inflammation of the airways. It is especially helpful in controlling nighttime symptoms of asthma. Blood levels of the drug must be measured on a regular basis, however. If levels get too high, they can cause an abnormal heart rhythm or convulsions.

BETA-RECEPTOR AGONISTS. Beta-receptor agonists are bronchodilators (pronounced brong-ko-die-LATE-urs), drugs that open up bronchi and bronchiole. They make it easier for air to get into and out of airways. They are best used for the relief of sudden asthma attacks and to prevent exercise-induced asthma. These drugs generally start acting within minutes and last for up to six hours. They are taken by mouth, by injection, or with an inhaler.

STEROIDS. Steroids are related to natural body hormones. They reduce or prevent inflammation and are very effective in relieving the symptoms of asthma. When taken over a long period of time by inhalation, steroids can reduce the frequency of asthma attacks. They can also make airways less sensitive to allergens. For these reasons, they are the strongest and most effective methods for treating asthma. They can control even the most severe cases of the disease and maintain good lung function.

On the other hand, steroids have a number of side effects, some of which are serious. They can cause stomach bleeding, loss of calcium from bones, cataracts in the eyes, and a diabetes-like condition. Long-term use of steroids can also result in weight gain, loss of some mental function, and problems with wound healing. In children, growth may be slowed. Steroids can be taken by mouth, by injection, or by inhalation.

LEUKOTRIENE MODIFIERS. Leukotriene (pronounced lyoo-kuh-TRI-een) modifiers are drugs that interfere with changes in the bronchi and bronchioles that occur during an asthma attack. They prevent airways from narrowing and the release of mucus. They are recommended in place of steroids for older children and adults who have mild, long-lasting cases of asthma.

OTHER DRUGS. Anti-inflammatory drugs are sometimes used to prevent asthma attacks over the long term in children. Cromolyn (pronounced KRO-muh-lun) and nedocromil are two such drugs. They can also be taken before exercise or when exposure to an allergen cannot be avoided. These drugs are safe but expensive. They must be taken on a regular basis, even if the patient has no symptoms.

A class of drugs known as anti-cholinergics (pronounced ko-luh-NER-jiks) can also be used in the case of severe asthma attacks. Atropine is an example of this class of drugs. Anti-cholinergics are usually taken in combination with beta-receptor agonists. The combination helps widen airways and reduce the production of mucus.

Immunotherapy is used when a person cannot avoid exposure to an allergen. Immunotherapy is a procedure that involves a series of injections of the allergen. The series must be continued over a very long period of time, usually three to five years. During this period, the amount of allergen given in a shot is gradually increased. As more and more allergen is given, the patient's body slowly builds up an immunity (resistance) to the allergen.

Immunotherapy also has its risks. Injecting an allergen can itself cause an asthmatic attack. Studies seem to indicate, however, that the procedure can be effective against certain types of allergens, such as house-dust mites, ragweed pollen, and cat dander.

Managing Asthma Attacks

A severe asthma attack requires immediate treatment. Patients usually require supplemental (extra) oxygen. In rare cases, a mechanical ventilator may be needed to help a patient breathe. Inhalation of a beta-receptor is often effective in treating serious asthma attacks. If the patient does not respond to a beta-receptor, an injection of steroids may be necessary. Follow-up treatments with steroids make a recurrence of the attack less likely.

Maintaining Control

Long-term control over asthma is based on the use of beta-receptor drugs. These drugs are taken with inhalers that monitor the dose. Patients are instructed how to properly use an inhaler to make sure they receive the amount of drug needed to keep their disease under control. Once that goal is achieved, the amount of beta-receptor taken can be reduced. Patients should be seen by a doctor on a regular basis, however (such as once every one to six months).

As early on as possible, asthma patients should be trained in the treatment and control of their disease. They should be taught how to monitor their symptoms so they will know when an attack is starting. Using a flow meter is essential to this process. Over-the-counter medications should be avoided. Patients should also have an action plan to follow if their symptoms become worse. This plan includes how to adjust their medication and when to seek medical help.

Calling an asthma specialist should be considered when:

  • There has been a life-threatening asthma attack or the disease has become severe and persistent (long-lasting).
  • Treatment for three to six months has not met its goals.
  • Some other condition, such as chronic lung disease, is complicating asthma.
  • Special tests, such as allergy skin testing, are needed.
  • Intensive steroid therapy has been necessary.

Hospitalization can sometimes be necessary for an asthma patient. That decision depends on a number of factors, such as the past history of serious attacks, severity of symptoms, current medication, and the availability of support at home.

PROGNOSIS


Most patients with asthma respond well when the best drug or combination of drugs is found. They are then able to lead relatively normal lives. More than half of all children diagnosed with asthma stop having attacks by the time they reach the age of twenty-one. Many others have less frequent and less severe attacks as they grow older.

A small minority of patients have progressively more trouble breathing as they grow older. These people run the risk of going into respiratory failure (loss of ability to breathe). They require immediate and intensive treatment.

PREVENTION


A number of steps can be taken to minimize or eliminate exposure to allergens and other factors that bring on an asthma attack. These steps include:

  • As much as possible, avoid contact between an asthma patient and family pets to which he or she is allergic. Keep the pet out of the bedroom and away from carpets and upholstered furniture. Remove all feathers from the house.
  • Avoid exposure to dust mites by removing wall-to-wall carpeting, reducing the humidity, and using special pillows and mattress covers. Remove stuffed toys or wash them each week in hot water.
  • Cockroach allergens can be eliminated by killing the insects with poison, traps, or boric acid. Do not use synthetic chemicals. Prevent cockroaches from returning by making sure that food and garbage are not left out.
  • Keep indoor air clean by vacuuming carpets once or twice a week while the patient is not present. Do use air conditioners during warm weather, but do not use humidifiers.
  • Avoid exposure to tobacco smoke.
  • Avoid outdoor exercise when air pollution levels are high.
  • Exposure to workplace allergens can be avoided by following simple precautions. Always wear a mask and, if possible, arrange to work in a safer area.

FOR MORE INFORMATION


Books

Adams, Francis V. The Asthma Sourcebook: Everything You Need to Know. 2nd edition. Los Angeles, CA: Lowell House, 1998.

Gershwin, M. Eric, and E. L. Klinglhofer. Asthma: Stop Suffering, Start Living, 2nd edition. Reading, MA: Addison-Wesley Publishing Co., 1992.

Hyde, Margaret O. Living With Asthma. New York: Walker & Company, 1995.

Weiss, Jonathan H. Breathe Easy: Young People's Guide to Asthma. Washington, DC: Magination Press, 1994.

Organizations

Asthma and Allergy Foundation of America. 1233 Twentieth Street NW, Suite 402, Washington, DC 20036. 8007ASTHMA. http://www.aafa.org.

National Asthma Education Program. 4733 Bethesda Avenue, Suite 350, Bethesda, MD 20814. (301) 4954484.

Web sites

"Ask NOAH About: Asthma." NOAH: New York Online Access to Health. [Online] http://www.noah.cuny.edu (accessed on June 15, 1999).

"Asthma Information Center." [Online] http://www.mdnet.de/asthma/home.cfm (accessed on October 5, 1999).

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asthma

asthma Disorder of the respiratory system in which the bronchi (air passages) of the lungs go into spasm, making breathing difficult. It can be triggered by infection, air pollution, allergy, certain drugs, exertion or emotional stress. Allergic asthma may be treated by injections aimed at lessening sensitivity to specific allergens. Otherwise treatment is with bronchodilators to relax the bronchial muscles and ease breathing; in severe asthma, inhaled steroids may be given. Children often outgrow asthma, while some people suddenly acquire the disease in middle age. Air pollution is increasing the number of asthma sufferers. See also bronchitis; emphysema; lungs

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Asthma

Asthma

A Breathless Story

What Is Asthma?

What Triggers Asthma?

Who Gets Asthma?

What Are the Symptoms?

How Is Asthma Diagnosed?

Why Is Treatment Needed?

How Is Asthma Treated?

How Are Inhaled Medicines Taken?

Breathing Easier

Resources

Asthma (AZ-ma) is a condition in which the airflow in and out of the lungs may be partially blocked by swelling, muscle squeezing, and mucus in the lower airways. These episodes of partial blockage, called asthma flares or attacks, can be triggered by dust, pollutants, smoke, allergies, cold air, or infections.

KEYWORDS

for searching the Internet and other reference sources

Breathing

Lungs

Pulmonary system

Respiratory system

A Breathless Story

When Stacy was young, her parents noticed that she seemed to get tired more quickly than her friends while playing. She also had repeated coughing spells, and her breathing was sometimes noisy. After examining Stacy, asking lots of questions, and having her use a little machine to measure her breathing, the doctor diagnosed her problem as asthma. As part of the way Stacy took care of herself, she sometimes had to take asthma medicine at school. This made her teachers and friends interested in learning more about asthma. When Stacy was 12, she began a schoolwide project with the help of her teacher and the nurse. The goal was to make her school more asthma-friendly. No smoking was allowed, even during after-school events. Extra steps were taken to keep the school as free as possible of things that can trigger asthma flares, such as dust, mold, cockroaches, and strong fumes from paint and chemicals. A plan was set up to let students with asthma take their own medicines at school. Special lessons were offered to all students and teachers about what asthma is and how to help a classmate who has it. The result was a school that was a healthier place not just for Stacy but for everyone.

What Is Asthma?

Several changes happen inside the airways in the lungs of people who have asthma. First, there is inflammation, or swelling, of the lining of the airways. Second, the swollen tissues make a thick, slippery substance called mucus (MYOO-kus). Third, the muscles around the airways may squeeze tight, causing the airways to narrow. These three processes inflammation, mucus production, and muscle constrictioncombine to reduce the size (the diameter) of the airways. That makes it harder to breathe, like trying to blow air through a narrow straw.

During an asthma attack, these changes get worse. The airways swell on the inside while they are being squeezed on the outside. At the same time, thick mucus plugs the smaller airways. The person may start to make whistling or hissing sounds with each breath. The persons chest may also feel tight. In addition, the person may cough to try to clear the lungs.

What Triggers Asthma?

People with asthma have what are sometimes called sensitized airways. Everyday things that cause little or no trouble for most people can sometimes cause people with asthma to have a flare or attack. These things are

known as asthma triggers. There are two main kinds of triggers. The first are allergens (AL-er-jens), or substances that trigger an allergy. Examples of allergens that may trigger asthma are pollens, molds, animal dander (small scales from fur or feathers), dust mites, cockroaches, and certain foods and medicines. Most of these allergy-causing substances enter the body through the air people breathe, but some are swallowed.

The second kind of asthma trigger has nothing to do with an allergy but causes the same kind of reaction in the airways. Asthma can be triggered or made worse by irritating substances in the air, such as tobacco smoke, wood smoke, fresh paint, cleaning products, perfumes, workplace chemicals, and air pollution. Some other triggers include cold air, sudden changes in air temperature, exercise, heartburn, and infections of the airways, such as a cold or the flu. Exactly which of these might trigger a reaction varies from person to person.

Who Gets Asthma?

Asthma is one of the most common health problems in the United States. The number of people with the condition has grown rapidly in recent years. The reason for this increase is not yet known. About a third of these people are children under age eighteen. Asthma is more common in African American children than in white children, although the reason for this is not clear. It may have to do with environmental conditions.

What Are the Symptoms?

Following are the most common symptoms of asthma. A person may have all, some, or just one of these symptoms:

  • Shortness of breath
  • Coughing, particularly if it lasts longer than a week
  • Wheezing (whistling or hissing sounds made primarily when breathing out)
  • A feeling of tightness or discomfort in the chest

The degree to which asthma interferes with a persons daily life varies significantly. Some people have ongoing problems. They may have attacks anywhere from a couple of times a week to almost constantly. Their ability to take part in physical activities may be limited until, with treatment, they are able to get their asthma under control. Those with milder problems are usually able to do whatever they want to do, so long as they reduce their environmental triggers, take their medicine as directed, and follow any other advice from their doctors.

Childhood asthma

Babies often wheeze when they have a cold or other infection of the airways, blockage of the airways, or other problems. This symptom may go away on its own with no ill effects. However, if the problem is severe, lasts a long time, or comes back, treatment may be needed. In older children, normal breathing should be quiet. Wheezing may be a sign of asthma, but it can also signal an infection, lung disease, heartburn, heart disease, a blood vessel blocking the airways, or even a piece of food or other object (such as part of a toy) lodged in the airway. In addition to noisy breathing, asthma in children can cause rapid breathing and frequent coughing spells. Parents may also notice that the child tires quickly during active play.

Nighttime asthma

Asthma tends to get worse at night. Nocturnal (or nighttime) asthma occurs while a person is sleeping. For some people, nocturnal asthma is one of many symptoms; other people seem to have coughing or wheezing only at night.

Exercise-related asthma

Up to four out of five people with asthma have trouble with noisy breathing during or after exercise. This

Four Centuries of Medical Research

The word asthma comes from the Greek word for panting, which is a symptom that occurs in several different pulmonary (lung) disorders. Asthma was first depicted as a disease rather than a symptom by the English chemist Thomas Willis (1621-1675).

In 1698, Sir John Floyer first gave the first formal account of an asthma attack or fit. However, an accurate diagnosis of asthma was not possible until the early nineteenth century when the celebrated French physician René Laënnec (17811826) invented the stethoscope.

During the early nineteenth century, asthma was treated in a variety of ways including whiffs of chloroform and even the smoking of ordinary tobacco.

is known as exercise-induced asthma. Other symptoms include coughing, a rapid heartbeat, and a feeling of tightness in the chest five to ten minutes after exercise. Cold or dry air, high pollen counts, air pollution, a stuffed-up nose, and an infection of the airways are all things that tend to make the problem worse. Types of exercise that may lead to wheezing include running, using a treadmill, and playing basketballin short, exercises that are aerobic (designed to increase oxygen consumption).

Job-related asthma

Occupational asthma is caused by breathing in fumes, gases, or dust while on the job. Asthma can start for the first time in a worker who was previously healthy, or it can get worse in a worker who already had the condition. Symptoms include wheezing, chest tightness, and coughing. Other symptoms that may go along with the asthma include a runny or stuffed-up nose and red, sore, itchy eyes. The asthma may last for a long time, even after the worker is no longer around the substance that caused it.

Severe attacks

Status asthmaticus (STA-tus az-MAT-i-kus) is a severe asthma attack that does not get better when the person takes his or her medicine as usual. This kind of attack is an emergency that must be treated right away in a hospital or doctors office, where other medicines may be used.

How Is Asthma Diagnosed?

The doctor will do a physical checkup and ask questions about symptoms and when they occur. In addition, the doctor may do various tests to help identify asthma and its causes. These are some of the tests that may be done:

Allergy tests

Allergy tests help identify which things a person is allergic to. Skin tests are most common. Tiny amounts of possible allergens are put on the skin, and the skin is checked to see which substances, if any, cause a reaction. In another type of allergy test, a blood sample is checked for certain antibodies, which are substances made in the blood to fight foreign or harmful things. People with allergies may have high levels of immunoglobulin E (IgE) antibodies. However, the blood test is generally not considered as sensitive as the skin test, and it cannot check for as many allergens.

Chest x-ray

An x-ray is an invisible wave that goes through most solid matter and produces an image on film. In this case, a special picture is made to show how the lungs look.

Lung-function tests

These tests show how well the lungs are working. In one test, the person blows into a device called a spirometer (spi-ROM-i-ter), which measures the amount of air going in and out of the lungs. Another test uses a peak flow meter to measure how fast the person can breathe air out of the lungs. A peak flow meter is a simple, hand-held device that can be used at home. Many people with asthma use peak flow meters regularly to check for early warning signs of an upcoming asthma attack. This gives them time to take certain medicines that can often stop the attack.

Why Is Treatment Needed?

Asthma that is not under control can cause many problems. People miss school or work, must go to the hospital, and can even die (rarely) because of asthma. With a doctor s help, though, it is possible to control asthma. People with well-controlled asthma have few, if any, symptoms during the day and can sleep well at night. They can also take part in their usual activities, including sports and exercise. However, the asthma does not go away just because the symptoms do. A person needs to keep taking care of the condition as part of life: avoiding triggers, not smoking, and living in a healthful, clean environment. This is true even if the asthma is mild.

How Is Asthma Treated?

Besides avoiding exposure to asthma triggers, the chief way that asthma is treated is with various medicines. One key to good control is taking the right medicine at the right time. There are two main kinds of asthma medicines: those that help with long-term control of the disease, and those that give short-term relief when a person is having an asthma attack.

Long-term control medicines

Long-term control medicines are taken every day to help prevent symptoms before they start. It may take several weeks for these medicines to produce their best results, though. The most effective ones work by reducing swelling in the airways. Many are inhaled, or breathed into the lungs. Not everyone needs such medicines. However, they may be very helpful for people who have daytime asthma symptoms three or more times a week or nighttime symptoms three or more times a month. These are some medicines for long-term control of asthma:

  • Inhaled corticosteroids (kor-ti-ko-STER-oids). These strong drugs prevent and reduce swelling in the airways. They also make the airways less sensitive to triggers. However, they work only if they are used regularly. These drugs are taken every day by people with long-lasting asthma. They are not the same as the unsafe steroids some athletes use to build muscles.
  • Other inhaled drugs. These medications also help prevent and reduce swelling in the airways and make the airways less sensitive. However, it can take four to six weeks of regular use before they start to work. These drugs are taken every day by people with long-term asthma, but they can also be used before exercise or contact with a trigger.
  • Oral corticosteroids. These drugs are taken by mouth in pill or liquid form. Unlike inhaled corticosteroids, they sometimes cause serious side effects when used for a long time. However, they can often be used safely for a short time to treat severe asthma attacks and to quickly bring asthma under control. They are sometimes taken every day or every other day by people with the most severe asthma.

Breathtaking Facts

  • More than 17 million people in the United States have asthma. Of these, almost 5 million are children.
  • About one in every ten children has asthma-like symptoms.
  • About three out of four children with asthma continue to have symptoms as adults.
  • Asthma results in about 3 million lost days of work each year among American adults.
  • According to the Centers for Disease Control and Prevention (CDC), between 1980 and 1994, the number of Americans who reported having asthma rose 75 percent.

Winning Ways

Jackie Joyner-Kersee (b. 1962) has often been called the worlds greatest female athlete. What many fans never suspect is that she is also an asthma patient. Joyner-Kersee became active in sports at age nine. As a teenager, she was an all-state player in basketball and a Junior Olympics champion in pentathlon, an athletic contest in which each person takes part in five different events. While still in high school, Joyner-Kersee began having trouble breathing. When she first found out that she had asthma, she did not take it seriously. She often skipped her medicine. After a serious asthma attack, though, she realized that she had to work to control the condition just as she worked to win at sports. After college, Joyner-Kersee went on to win six Olympic medals as well as to break the world and Olympic records in the heptathlon, an athletic contest with seven different events: 100-meter hurdles, high jump, shot put, 200-meter dash, long jump, javelin, and 800-meter race. Today she serves as a spokesperson for groups that educate the public about asthma.

  • Long-acting bronchodilators (brong-ko-DY-lay-tors). These drugs relax the muscles around the airways, making it easier to breathe. They can prevent or reduce narrowing of the airways. However, they keep working only if they are used regularly. These drugs are inhaled or taken by mouth in a pill. Some are especially useful for preventing nighttime or exercise-related asthma.
  • Antileukotrienes (an-ti-loo-ko-TRY-eens). This is a new class of asthma drugs. These drugs prevent and reduce swelling in the airways and make the airways less sensitive to triggers. They also prevent squeezing of the muscles around the airways. These drugs are taken regularly by mouth in a pill. So far, they have been used mainly for mild asthma in patients of age twelve and older.
  • Allergy vaccines. In some cases, a persons asthma symptoms can be prevented or lessened by giving a course of special allergy injections over months or years. These shots contain small amounts of the allergens that are triggering the persons asthma. The course of injections causes the person to become less sensitive to the allergen when exposed to it.

Short-term relief medicines

Short-term relief medicines are taken only when needed to relax and open the airways quickly. They can be used to relieve symptoms or to prevent them if a persons peak flow meter readings begin to drop, signaling an upcoming asthma attack. However, the effects last for only a few hours. They cannot keep the symptoms from coming back the way long-term control medicines can. These drugs are inhaled and are taken at the first sign of trouble or before contact with a trigger.

Medicines that provide short-term relief of asthma are called short-acting bronchodilators. These drugs relax the muscles around the airways, making it easier to breathe. They begin to work within five minutes, and their effects last for four to six hours. Such drugs are taken right after symptoms start or just before exercise.

How Are Inhaled Medicines Taken?

Many asthma medicines are made to be breathed into the lungs. Such inhaled drugs go straight to the place where they are needed. The most popular device for taking inhaled medicines is a metered dose inhaler, which gets the drug to the lungs in exact amounts. The inhaler is a small, hand-held canister with a button that the person pushes to make the medicine spray out. Often a tube, called a spacer, is attached to the canister to make it easier to use.

Another type of device that is sometimes used to take inhaled medicines is a nebulizer (NEB-you-lyz-er), which turns liquid medicine into a very fine mist. These devices are helpful for babies, young children, and elderly or very sick adults who would have trouble handling a metered dose inhaler.

Breathing Easier

People with asthma should try to figure out what makes their symptoms worse and take steps to avoid or control those things. Here are a few ways that many people control some common asthma triggers. Not all of them will work for everyone.

Pollens and outdoor molds

To control pollens and outdoor molds, people with asthma often:

  • keep windows and doors closed when pollen or mold spore counts are high.
  • avoid walking in gardens and fields when they are in bloom and when pollen and mold spore counts are highest.
  • ride with the car windows shut and the air conditioner on during pollen season.
  • ask their doctors about starting or increasing a long-term control medicine before peak pollen season begins.

Indoor molds

To control indoor molds, people with asthma often:

  • fix leaky faucets, pipes, and other sources of water.
  • clean moldy surfaces with a product that contains bleach.
  • remove wallpaper, which can have mold growing on it.
  • get rid of houseplants, which can gather mold and dust.

Animal dander

Dander is small scales from the hair of animals, like cats, and from bird feathers. Some people are allergic to it, and people with asthma often:

  • keep pets with fur or feathers out of their homes, if possible.
  • have pets stay out of bedrooms, in particular, and keep bedroom doors closed.
  • remove carpets and cloth-covered furniture, or keep pets away from these things.
  • use polyester-fill rather than feather pillows, and avoid down quilts.

Dust mites

People with asthma often find that they are allergic to dust because of the tiny animals that live in the dust, called mites. Many people with asthma find that it helps to keep their homes especially clear of dust. For example, they:

  • wash their bedding each week in hot water (it must be hotter than 130 degrees F to kill mites).
  • enclose mattresses and pillows in special dust-proof covers, or wash pillows each week in hot water.
  • try not to sleep or lie on cloth-covered furniture or cushions.
  • remove carpets in bedrooms and those laid on concrete.
  • keep stuffed toys out of beds, and wash the toys each week in hot water.
  • wear a dust mask while vacuuming, or have someone else do the vacuuming.

Cockroaches

Many people with asthma are sensitive to cockroach droppings and make a special effort to get rid of these stubborn creatures by:

  • keeping all food out of bedrooms.
  • storing food and garbage in closed containers and never leaving food or crumbs sitting around.
  • using poison bait, powder, gel, paste, or traps (following label instructions) to kill cockroaches.
  • staying out of the room until the odor goes away if a spray is used to kill roaches.

Certain foods and medicines

It is important to:

  • avoid foods that have caused problems in the past.
  • tell the doctor about any past reactions to medicines.

Smoke and strong odors

Smoking is not good for anyone, the person smoking or people who are in the same room with tobacco smoke. People with asthma are especially endangered by tobacco smoke and find it is best not to smoke, to ask other family members to quit smoking, and to ask visitors not to smoke.

People with asthma also:

  • avoid using a wood-burning stove, kerosene heater, or fireplace, if possible.
  • try to stay away from strong odors and fumes, such as perfume, hairspray, and fresh paint.

Exercise

It is healthy for just about everyone to exercise, and people with asthma are no exception. To make their exercise and sports more enjoyable, people with asthma usually:

  • warm up for six to ten minutes before exercising.
  • avoid exercising outside when air pollution or pollen counts are high or when the air is cold.
  • pick activities that do not cause symptoms; running sports are the most likely to trigger problems.
  • ask a doctor about taking medicine before exercise to prevent symptoms.

See also

Allergies

Emphysema

Heartburn (Dyspepsia)

Resources

Books

American Lung Association and Norman H. Edelman. The American Lung Association Family Guide to Asthma and Allergies: How You and Your Children Can Breathe Easier. New York: Back Bay Books, 1997.

Weiss, Jonathan H. Breathe Easy: Young Peoples Guide to Asthma. Washington, DC: Magination Press, 1994.

Organizations

Allergy and Asthma Network/Mothers of Asthmatics, 2751 Prosperity Avenue, Suite 150, Fairfax, VA 22031. Telephone 800-878-4403 http://www.aanma.org

American Academy of Allergy, Asthma and Immunology, 611 East Wells Street, Milwaukee, WI 53202. Telephone 414-272-6071 http://www.aaaai.org

American College of Allergy, Asthma and Immunology, 85 West Algonquin Road, Suite 550, Arlington Heights, IL 60005. Telephone 847-427-1200 http://allergy.meg.edu

American Lung Association, 1740 Broadway, New York, NY 10019. Telephone 800-LUNG-USA

http://www.lungusa.org

Asthma and Allergy Foundation of America, 1125 Fifteenth Street N.W., Suite 502, Washington, DC 20005. Telephone 800-7-ASTHMA http://www.aafa.org

Asthma Information Center. This website is run by the Journal of the American Medical Association. http://www.ama-assn.org/special/asthma/asthma.htm

U.S. National Heart, Lung, and Blood Institute, NHLBI Information Center, P.O. Box 30105, Bethesda, MD 20824-0105. NHLBI has an Asthma Management Model System and runs a National Asthma Education and Prevention Program. Telephone 301-592-8573 http://www.nhlbisupport.com/asthmahttp://www.nhlbi.nih.gov

The U.S. Centers for Disease Control, located in Atlanta, Georgia, posts information on asthma at http://www.cdc.gov/nceh/programs/asthma/default.htm

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asthma

asth·ma / ˈazmə/ • n. a respiratory condition marked by spasms in the bronchi of the lungs, causing difficulty in breathing. It usually results from an allergic reaction or other forms of hypersensitivity.

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asthma

asthma XIV. — Gr. ásthma, -mat-.
So asthmatic XVI.

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asthma

asthmaAlabama, clamour (US clamor), crammer, gamma, glamour (US glamor), gnamma, grammar, hammer, jammer, lamber, mamma, rammer, shammer, slammer, stammer, yammer •Padma • magma • drachma •Alma, halma, Palma •Cranmer • asthma • mahatma •miasma, plasma •jackhammer • sledgehammer •yellowhammer • windjammer •flimflammer • programmer •amah, armour (US armor), Atacama, Brahma, Bramah, charmer, cyclorama, dharma, diorama, disarmer, drama, embalmer, farmer, Kama, karma, lama, llama, Matsuyama, panorama, Parma, pranayama, Rama, Samar, Surinamer, Vasco da Gama, Yama, Yokohama •snake-charmer • docudrama •melodrama •contemner, dilemma, Emma, emmer, Jemma, lemma, maremma, stemma, tremor •Elmer, Selma, Thelma, Velma •Mesmer •claimer, defamer, framer, proclaimer, Shema, tamer

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