Asthma

What is Asthma?

Asthma is a chronic lung condition. It is characterized by difficulty in breathing.
People with asthma have extra sensitive or hyperresponsive airways. The airways react by narrowing or obstructing when they become irritated. This makes it difficult for the air to move in and out. This narrowing or obstruction can cause one or a combination of the following symptoms:

• wheezing
• coughing
• shortness of breath
• chest tightness

This narrowing or obstruction is caused by:

• Airway Inflammation meaning that the airways in the lungs become red, swollen and narrow)
• Bronchoconstriction (meaning that the muscles that encircle the airways tighten or go into spasm)
• Provoking Factors

Two factors provoke asthma:

1. Triggers result in tightening of the airways (bronchoconstriction).
2. Causes (or inducers) result in inflammation of the airways.

Triggers

• Triggers irritate the airways and result in bronchoconstriction.
• Triggers do not cause inflammation and therefore do not cause asthma.
• Symptoms and bronchoconstriction caused by triggers tend to be immediate, short-lived, and rapidly reversible.
• Airways will react more quickly to triggers if inflammation is already present in the airways.

Common triggers of bronchoconstriction include everyday stimuli such as:

• Cold air
• Dust
• Strong fumes
• Exercise
• Inhaled irritants
• Emotional upsets
• Smoke

Smoke acts as a very strong trigger. Second-hand smoke has been shown to aggravate asthma symptoms, especially in children. The effects of one cigarette linger in the home for 7 days, and therefore it is very important to provide a SMOKE-FREE HOME for all children. In fact, some health care workers feel that smoking in a home where there is a child with asthma is a form of child abuse.
Children should not be exposed to a polluted environment over which they have no control.
Causes or Inducers

• In contrast to triggers, inducers cause both airway inflammation and airway hyperresponsiveness and hence are recognized as causes of asthma.
• Inducers result in symptoms which may last longer, are delayed and less easily reversible than those caused by triggers.

The most common inducers are:

• Allergens
• Viral Infections

Allergens
Inhalant allergens are the most important inducer or cause of inflammation and airway hyperresponsiveness. Probably 75-80% of young asthmatics are allergic.
The most common inhaled allergens include:

• pollen (grasses, trees and weeds)
• animal secretions (cats and horses tend to be to the most allergen causing)
• molds
• house dust mites

Exposure to an allergen (e.g. cat secretions) may cause immediate symptoms such as wheeze or cough. This occurs because airways are hyperresponsive and react by tightening. These symptoms can easily be relieved by a bronchodilator (such as Ventolin®). However, about 4 and 7-8 hours after exposure to the secretion, a late response occurs which is caused by the inflammation. This inflammation develops over time. Because of the late response, it is often difficult for the patient and physician to identify what is actually causing the asthma.
Respiratory Viral Infections
In children, respiratory viral infections may cause a deterioration in his or her asthma. A respiratory viral infection is probably one of the most common causes of asthma. In some cases, the influenza vaccine is indicated. This may help to prevent respiratory complications that can occur from developing influenza. This vaccine is contraindicated for those individuals who have an allergy to eggs.

How is Asthma diagnosed?

Making a correct diagnosis is extremely important: if asthma is correctly diagnosed it can be treated appropriately.
The diagnosis of asthma involves all of the following:

1. A detailed history which would include:
   • family history of asthma, allergies, hay fever, eczema; children will have a greater chance of developing the above if there is a family history of allergies and asthma
   • child’s medical history including:
     • when parents first noticed the child developed breathing problems; history of nasal stuffiness (rhinitis), itchy eyes (allergic conjunctivitis) and eczema, which are common accompaniments to asthma, and hives (urticaria).
     • history of recurrent and persistent cough following a cold, frequent colds, croup, seasonal changes (i.e. worse in the spring and fall), exercise limited by breathing problems, waking at night with symptoms.
     • school absences, emergency room visits (hospitalizations).
     • environmental history
2. Physical examination: i.e. listening to the lungs with a stethoscope; examination of nasal passages etc.
3. Chest x-ray may be done once to exclude the possibility of breathing problems being caused by something other than asthma.
4. Blood tests and sputum studies may be done.
5. Allergy prick skin testing: Skin tests can confirm the presence or absence of allergies; they must, however, be correlated to the history of symptoms.
6. Spirometry is a breathing test which measures the amount and rate at which air can pass through airways; if the airways are narrowed because of inflammation it will be more difficult for air to pass through the airways. This will result in changes in spirometry values. With children under the age of five years, generally this test is not indicated because there is a certain amount of effort and cooperation required. However, this is a very dependable method of making a diagnosis. Any difficult or troublesome asthma should be confirmed objectively by performing spirometry.
7. Challenge tests: Exercise challenge tests and methacholine inhalation tests are procedures used most frequently in clinical laboratories to evaluate airway responsiveness.
8. Differential diagnosis: Other possible causes of shortness of breath, wheeze, cough and chest tightness must be investigated in order to rule these out. i.e. such as heart disease, other lung conditions, gastroesophageal reflux.
9. A trial use of asthma medications: If asthma medications are taken and improvement in symptoms is seen this further supports the diagnosis of asthma.

Because of the variability of symptoms (meaning symptoms can become worse and improve over time) a diagnosis cannot always be made immediately.

How is Asthma managed?

Patient Education

Patient education is an important area where asthma treatment can be improved. Asthma is common and controllable. Asthma is a disease that is variable, meaning that symptoms may get worse and may improve over time. Because of this variability it is often necessary to review and change the treatment. In order to enhance the patient-physician relationship, the patient must be familiar with the following:

• Nature of the disease; identifying provoking factors
• Nature of medications and side effects
• Proper technique of using devices
• Goals of treatment
• Early recognition of worsening control
• Written Action Plan
• Asthma Diary Form

The patient with this type of knowledge can communicate to the physician in order to work out an appropriate treatment plan. The goals of treatment should be understood and agreed upon by both the physician and the patient.
Long Term Asthma Management
Environmental Control
Environmental control should always be initiated along with taking the appropriate medications. If exposure to inducers are avoided, less medication is required.
It is not always easy to identify what inducer is making the asthma worse. It often means reviewing the history of symptoms carefully i.e. keeping track of the symptoms.
Controlling the inside and outside environment at home and in school, should be considered for those people who have identified allergies. For example:

• House dust mites: Dust mites are small parasites that live off the dead skin that we shed. Decrease exposure by enclosing mattress and box spring in plastic and washing all bed sheets and blankets in hot water once a week.
• Pets: If allergic to pets, animals should not be allowed in the house; this can include animals such as dogs, cats, gerbils and birds. People with identified animal allergies should not care for the pet.
• Smoke: No smoking in the home should be allowed at any time.
• Mold: Remove the mold wherever and whenever mold is found. Bleach can be used for this. The source of mold should be eliminated.
• High humidity: Increased moisture in the home can encourage mold growth and house dust mites, which require greater than 50% humidity to survive. Humidifiers, if not cleaned properly, can grow bacteria and produce a residue which some people find irritating to their lungs.
• Pollens: It may be necessary to avoid playing outside during times of high pollen counts. Pollen counts are usually greater in hot, dry and/or windy weather and usually between 4-10 AM. Camping and raking leaves will expose the person to pollens.

Medication Management

• involves a CONTINUUM approach
• involves introduction or change in anti-inflammatory treatment
• add or increase medication – for increased symptoms
• decrease medication – when symptom free

How is Asthma treated?

The successful approach to asthma management depends on using anti-inflammatory medications with bronchodilators as needed for immediate and occasional relief of symptioms.

1. Anti-Inflammatory – Preventers: Anti-inflammatories are used to treat the inflammation that is caused by exposure to inducers.
2. Bronchodilators – Relievers (Rescue): Bronchodilators are used to relieve the bronchoconstriction provoked by triggers.

The successful approach to asthma management, both in and out of hospital settings, is dependent upon the use of anti-inflammatory treatments with bronchodilators being prescribed for immediate and occasional relief of symptoms.
It has been shown that regular, frequent use of bronchodilator therapy may actually worsen the asthma. Again this stresses the need for adding anti-inflammatory medications if bronchodilator therapy is required often to control symptoms.
Anti-Inflammatory Medications (Preventers)

• prevent and reduce inflammation, swelling and mucus
• prevent symtpoms such as cough, wheeze and breathlessness
• need to be taken on a regular basis
• are slow acting (hours or weeks)

Types of Anti-Inflammatory Drugs
There are steroidal and non-steroidal anti-inflammatory drugs. The most common ones include:
Steroids

• beclomethasone (Beclovent®, Vanceril®, Becloforte®)
• budesonide (Pulmicort®)
• flunisolide (Bronalide®)
• fluticasone (Flovent®)

Non-Steroidal

• sodium cromoglycate (Intal®)
• nedocromil (Tilade®)

Corticosteroid Inhalers
Corticosteroid drugs are the most effective preventer.
They work by reducing and preventing airway inflammation, swelling and mucus.
They must be used regularly and DO NOT have immediate effects. This means they have NO VALUE when an effect is needed in minutes.
A stepwise approach to treatment of asthma involves the introduction or change in anti-inflammatory medication.
Increased asthma symptoms indicate the need to increase the anti-inflammatory in order to achieve control. As control is achieved and the patient remains symptom free over a period of time (as specified by the physician), a decrease of medications can be initiated by the patient.
Side Effects of Corticosteroid Inhalers

• few side effects at low doses
• high doses MAY cause growth suppression; studies have shown that children whose asthma is not controlled do not grow as quickly as other children.
• side effects, in general, are usually restricted to the throat:
  • hoarseness and sore throat
  • thrush or yeast infection
  • This can be prevented by rinsing the mouth and gargling, and by using a holding chamber.

Corticosteroid Tablets
Corticosteroid tablets or Prednisone®:

• are used when inflammation becomes severe
• reduce inflammation, swelling & mucus, and help bronchodilators work better
• start to work within a few hours, but may take several days to have a full effect
• often are used for short periods of time to get the inflammation under control
• there are many side effects if used long-term, such as water retention, bruising, puffy face, increased appetite, weight gain and stomach irritation

Other Preventers
Other preventers are Intal® and Tilade®. They are non-steroidal and again, are used to reduce the inflammation.

• sodium cromoglycate (Intal®)
  • for mild asthma
  • can protect against the effects of cold air and exercise
  • requires 4-6 weeks to be effective
  • few side effects.
• nedocromil (Tilade®)
  • similar to Intal®
  • requires 3-4 weeks to be effective
  • has a bad taste
  • fewer doses/cannister; therefore, you may need more than one cannister per month.
• ketotifen (Zaditen®)
  • used for mild asthma
  • may be useful for asthmatics who also have hay fever
  • helps to reverse inflammation of airways
  • can be used orally: comes in tablets or syrup
  • requires regular use of 8-12 weeks to be effective
  • side effects include drowsiness and weight gain

Leukotriene Receptor Antagonists
Leukotriene receptor antagonists are a new class of oral asthma medications.
They act against one of the inflammatory components of asthma and provide protection against bronchoconstriction when taken before exercise or exposure to allergens or cold. They decrease both the early and late asthmatic response.
Because they are still so new, the actual role of leukotriene receptor antagonists in the management of asthma is not clear, i.e. it is not fully understood who exactly will benefit most when taking these medications.
Examples of leukotriene receptor antagonists available in Canada are:

• zafirlukast (Accolate®)
• montelukast (Singulair®)

Don’t let asthma manage you; you manage your asthma.