Sunday, April 29, 2007

ABOUT CHILDHOOD ASTHMA

Asthma is one of the most common chronic diseases of childhood.

In 2004, an estimated 4 million children under 18 years old have had an asthma attack in the past 12 months, and many others have "hidden" or undiagnosed asthma.1 Asthma is the most common cause of school absenteeism due to chronic disease and accounted for an estimated 14 million lost school days.2

Even though asthma cannot be cured, it can almost always be controlled. For this reason, the American Lung Association has chosen control of childhood asthma as one of its top priorities.

The better you and your child understand asthma and its treatment, the better you will be able to control it.

HOW DO NORMAL LUNGS FUNCTION?

Lungs allow oxygen to enter the body in exchange for its waste product, carbon dioxide. As the air passes through the nose and mouth, it is rapidly warmed and moistened to avoid injury to the delicate lining of the airways.

The nose and airways also trap large particles (dust, pollen, molds, bacteria) and chemicals (smoke, sprays, odors), which could cause serious injury to the lungs.

The air is then transported through smaller airways. These airways branch like a tree, so that millions of small airways can carry oxygen to the tiny air sacs called alveoli.

The airways have a delicate cellular lining (mucosa), which is coated with a thin layer of mucus, as is present in the nose. Foreign particles are trapped by the sticky mucus and eventually removed from the airways through the normal cleansing process.

The process is assisted by the movement of tiny "whip-like" structures called cilia which move the mucus and trapped foreign particles up toward the mouth and nose where they are coughed and sneezed out or swallowed.

Bundles of muscles surround the airways, and the contraction of these muscles allows airways to selectively direct the flow of air.

WHAT IS ASTHMA?

Asthma is an inflammatory condition of the bronchial airways. This inflammation causes the normal function of the airways to become excessive and over-reactive, thus producing increased mucus, mucosal swelling and muscle contraction.

These changes produce airway obstruction, chest tightness, coughing and wheezing. If severe this can cause severe shortness of breath and low blood oxygen.

Each individual suffers a different level of severity. Virtually, all children with asthma, however, do enjoy a reversal of symptoms until something triggers the next episode.

WHAT IS THE CAUSE OF ASTHMA?


Inflammation of the airways is the common finding in all asthma patients. Recent studies indicate that this inflammation is virtually always causative in the asthmatic condition. This inflammation is produced by allergy, viral respiratory infections, and airborne irritants among others.

Childhood asthma is a disorder with genetic predispositions and a strong allergic component. Approximately 75 to 80 percent of children with asthma have significant allergies.3

Studies indicate that allergic reactions produce both immediate and late phase (delayed) reactions. Research indicates that approximately half of the immediate allergic reactions to inhaled allergens are followed by a late phase reaction.

This late phase reaction produces more serious injury and airway inflammation. This airway inflammation leads to irritability or hyperresponsiveness of the airways. In addition, prolonged airway inflammation can cause scarring.

WHAT ARE THE SIGNS AND SYMPTOMS?

Wheezing, though characteristic of asthma, is not the most common symptom. Coughing is noted especially with even "hidden" asthma when wheezing may not be apparent to the patient, his or her family or the physician.

Any child who has frequent coughing or respiratory infections (pneumonia or bronchitis) should be evaluated for asthma.

The child who coughs after running or crying may have asthma. Recurrent night cough is common, as asthma is often worse at night.

Infants who have asthma often have a rattly cough, rapid breathing and may have an excessive number of "pneumonias," episodes of bronchitis or "chest colds." Obvious wheezing episodes might not be noted until after 18 to 24 months of age.4

Chest tightness and shortness of breath are other symptoms of asthma that may occur alone or in combination with any of the above symptoms. Since these symptoms can occur for reasons other than asthma, other respiratory diseases must always be considered.

In a young child the discomfort of chest tightness may lead to unexplained irritability.

Remember: Any child who has frequent coughing or respiratory infections (pneumonia or bronchitis) should be evaluated for asthma.

WHAT ABOUT HIDDEN ASTHMA?

Until rapid breathing, wheezing and coughing become obvious, the condition of many children with asthma will go undetected. These children with asthma usually suffer some degree of airway obstruction; and unless it is brought under control, the children may suffer respiratory illness more frequently than necessary.

Hidden asthma, however, can produce so few recognizable symptoms that even the physician might not be able to distinguish abnormal breath sounds with his or her stethoscope but it may cause subtle problems such as limitation of physical activity. Pulmonary function testing usually reveals these cases of airway obstruction.

WHAT USUALLY TRIGGERS ASTHMA?

Episodes of asthma often are triggered by some condition or stimulus. Common triggers of asthma are:

Exercise

Running can trigger an episode in over 80 percent of children with asthma. Bronchodilator medications used before exercise can prevent most of these episodes. With proper control of asthma, most children with asthma can participate fully in physical activities.

There might be exceptions, such as prolonged running, especially during cold weather, allergy season or illness from a "cold." Swimming seems to be the least asthma-provoking form of exercise. However recently there has been concern about excessively chlorinated pools precipitating asthma episodes.

Infections

Respiratory infections, including the flu, frequently trigger severe episodes of asthma. Research indicates that these infections are most frequently produced by viruses, rather than bacteria. Antibiotics are of no benefit for viral infections and thus may be of little value in an asthma episode. It is important for all children with asthma to get vaccinated for the flu each year. American Lung Association Research has shown that the vaccination itself will not precipitate an attack.

Bronchodilator medication, good hydration, and when indicated, corticosteroids are required to control an asthma episode triggered by viral infections. Therefore, a parent should not be surprised if the physician does not prescribe an antibiotic when a child is having a respiratory infection and asthma. On the other hand, the doctor may decide to use an antibiotic if he or she suspects bacterial infection, such as sinusitis or bronchitis.

Note: Chronic sinusitis in childhood due to bacteria can be a very stubborn chronic trigger for asthma. Treatment for 10 days with antibiotics may not be effective. In these children, sinus x-rays are frequently required to diagnose the underlying condition.

Antibiotic treatment for 3 to 4 weeks or longer may be required to completely eradicate these infections. Asthma may also be triggered by an ear infection or bronchitis which would also require antibiotic therapy.

Allergy

Asthma symptoms of many children with asthma are triggered by allergies. Allergic children suffer reactions to ordinarily harmless material (pollen, mold, food, animals).

During an allergic reaction, chemicals such as histamine are released from specialized cells. This may produce swelling of the lining of the airway, excessive mucus secretion and muscle contraction in the airways. In this way, an allergy can provoke an asthma episode.

The allergens involved are common indoor inhalants (dust mites, feathers, molds, pets, insects (especially roaches), outdoor inhalants (molds and pollens), or ingested foods (milk, soy, egg, etc.). Foods are much less frequent causes of asthma. These allergens may produce low-grade reactions which are of no obvious consequence: however, daily exposure to these allergens may result in a gradual worsening of asthma.

Allergy may be the cause of unrecognized or hidden asthma. Minor allergic reactions can be more important than more obvious or severe reactions, in that an allergic person tends to avoid exposure to allergens that have caused severe reactions, while ignoring the minor allergens.

For instance, if your child is highly allergic to cats and develops severe wheezing when he or she is around them, you'll probably avoid cats at all costs. But what about your dog that sleeps with your child and doesn't cause obvious wheezing? This could be an important factor. If so, skin testing usually will reveal any reaction the child has to the dog. The child would then do better with both the cat and dog removed from his or her environment.

Irritants

Cigarette smoke, air pollution, strong odors, aerosol sprays and paint fumes are some of the substances which irritate the tissues of the lungs and upper airways. The reaction (cough, wheeze, phlegm, runny nose, watery eyes) produced by these irritants can be identical to those produced by allergens.

Cigarette smoke is a good example, because it is highly irritating and can trigger asthma. Most people are not allergic to cigarette smoke; that is, there is no known immunologic reaction. Nevertheless, this irritant can be more significant than any allergen.

Secondhand smoke can cause serious harm to children. An estimated 400,000 to one million asthmatic children have their condition worsened by exposure to secondhand smoke.5

Irritants must be recognized and avoided. Cigarette smoking certainly should be avoided in the home of any child with asthma. It has been shown that when the parents of a child with asthma stop smoking, the child's asthma often improves.

Weather

Children with asthma have cited a number of climatic conditions as trigger factors. Many identify cold air as triggering asthma. Pulmonary function studies demonstrate that breathing cold air provokes asthma in most children with asthma.

Precautions may be necessary to avoid inhalation of cold air, such as wearing a special ski mask designed for this purpose. A heavy scarf, worn loosely over the nose and mouth, will also help avoid cold air induced asthma.

The weather affects outdoor inhalant allergens (pollens and molds). On a windy day more allergens will be scattered in the air, while a heavy rainfall will wash the air clean of allergens. On the other hand, a light rain might wash out pollen, but actually increase mold concentration.

There does not seem to be one best climate for all children with asthma, and moving to a new area to reduce asthma severity often is met with disappointment in the long run, even after initial improvement.

Emotions

A common misbelief is that children with asthma have a major psychological problem that's caused the asthma. Emotional factors are not the cause of asthma; however,emotional stress can infrequently trigger asthma.

A child's asthma might only be noticeable after crying, laughing or yelling in response to an emotional situation. These normal "emotional" responses involve deep rapid breathing which in turn can trigger asthma, as it does after running.

Emotional stress itself (anxiety, frustration, anger) also can trigger asthma, but the asthmatic condition precedes the emotional stress. Therefore, a child's asthma is not "in his or her head," as many people believe.

Emotions are associated with asthma for another reason. Many children with asthma suffer from severe anxiety during an episode as a result of suffocation produced by asthma. The anxiety and panic can then produce rapid breathing or hyperventilation, which further triggers the asthma.

During an episode, anxiety and panic should be controlled as much as possible. The parent should remain calm, encourage the child to relax and breathe easily and give appropriate medications.

Treatment should be aimed at controlling the asthma. When asthma is controlled, emotional stress will be reduced and other emotional factors can then be dealt with more effectively. Any chronic illness, especially if uncontrolled, can have associated secondary psychological problems. More severe psychological problems require a specialist to help the child and his or her family.

REMEMBER

Asthma is...

  1. An inflammatory condition of the airways caused by allergens, irritants and respiratory infections.
  2. Triggered by many different stimuli (trigger factors) that activate an over-reactive airway system.

Is reversible and controllable (with only a few rare exceptions.)

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