Understanding Asthma: Causes, Symptoms, and Key Factors

Asthma

Alzheimer’s disease (AHLZ-high-merz) is a progressive brain disorder that gradually destroys a persons memory and ability to learn, reason, make judgments, communicate and carry out daily activities.

What is Asthma?

Asthma is a chronic lung condition. It is characterized by difficulty in breathing. Individuals with asthma have hyperresponsive airways or extra sensitive Airways can constrict or become blocked when they become irritated, which can lead to discomfort. The air has more difficulty flowing in and out When the airways become blocked or narrow, it can lead to various signs and symptoms including:

wheezing
coughing
shortness of breath
chest tightness

This narrowing or obstruction is caused by:

Airway Inflammation means 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:

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

Triggers tend to cause irritation in the airways which can then lead to bronchoconstriction.
Asthma is not caused by inflammatory triggers, hence it cannot be associated with them.
Triggers of symptoms and bronchoconstriction tend to manifest quickly, not last long and can be reversed swiftly.
When airways already have inflammation, they will be more responsive to triggers and react more rapidly.

Bronchoconstriction, an airway tightening, can be caused by everyday things such as:

Cold air
Dust
Strong fumes
Exercise
Inhaled irritants
Emotional upsets
Smoke

Smoke acts as a very strong trigger. Studies have suggested that second-hand smoke, especially for children, can make asthma symptoms worse. To ensure the well-being of children, creating a SMOKE-FREE HOME is essential as it guarantees that the harmful effects of smoking will be absent from their environment for up to 7 days. Healthcare workers widely regard smoking in a home where there is an asthmatic child as an act of child abuse.
Children should not be exposed to a polluted environment over which they have no control.

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

The most common inducers are:

Allergens

Inhalant allergens are strongly linked to inflammation and hyperresponsiveness of the airways. 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 the most allergen-causing)
molds
house dust mites

Exposure to an allergen (e.g. cat secretions) may cause immediate symptoms such as wheezing or coughing. This occurs because airways are hyperresponsive and react by tightening. These symptoms can easily be relieved by a bronchodilator (such as Ventolin®). After some time, 4 to 8 hours after being exposed to the secretion, a delayed response takes place due to 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 asthma.

Respiratory Viral Infections

In children, respiratory viral infections may cause a deterioration in or their asthma. Asthma is often linked to a viral respiratory infection, which is one of the most common types of infection. In certain situations, it is recommended to receive the influenza vaccine. 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.

Asthma Diagnosis

It is imperative to get the diagnosis right when it comes to asthma. This is because, with a correct diagnosis, appropriate treatment can be provided for better results.
The diagnosis of asthma involves all of the following:

A detailed history would include:
- family history of asthma, allergies, hay fever, or 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:
  - Parents first noticed their child had difficulty breathing and other usual symptoms such as rhinitis, allergic conjunctivitis, eczema, and urticaria. These usually signify that the individual may be suffering from asthma.
  - history of recurrent and persistent cough following a cold, frequent cold, croup, seasonal changes (i.e. worse in the spring and fall), exercise limited by breathing problems and waking at night with symptoms.
  - school absences, and emergency room visits (hospitalizations).
  - environmental history
Physical examination: i.e. listening to the lungs with a stethoscope; examination of nasal passages etc.
A chest x-ray may be done once to exclude the possibility of breathing problems being caused by something other than asthma.
Blood tests and sputum studies may be done.
Allergy prick skin testing: Skin tests can confirm the presence or absence of allergies; they must, however, be correlated to the history of symptoms.
Spirometry is a breathing test that measures the amount and rate at which air can pass through the 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.
Challenge tests: Exercise challenge tests and methacholine inhalation tests are procedures used most frequently in clinical laboratories to evaluate airway responsiveness.
Differential diagnosis: Other possible causes of shortness of breath, wheezing, cough, and chest tightness must be investigated in order to rule these out. i.e. such as heart disease, other lung conditions, and gastroesophageal reflux.
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.

Asthma Management

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 with 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.

Environmental Control

Environmental control should always be initiated along with taking the appropriate medications. If exposure to inducers is avoided, less medication is required.

It is not always easy to identify what inducer is making 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. Reduce exposure by encasing the mattress and box spring in plastic, and washing all bed linens and blankets in hot water on a weekly basis.
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 their 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. If not taken care of regularly, humidifiers can become a breeding ground for bacteria and emit particles that may cause respiratory issues for many.
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 the introduction or change in anti-inflammatory treatment
add or increase medication – for increased symptoms
decrease medication – when symptom-free

Asthma Treatment

Asthma management is best achieved through the use of anti-inflammatory medications in combination with bronchodilators when necessary. This helps to obtain immediate and occasional relief from symptoms associated with the disorder.

Anti-Inflammatory – Preventers: Anti-inflammatories are effective in treating inflammation that may be a result of specific elements.
Bronchodilators – Relievers (Rescue): Bronchodilators are used to help ease the narrowing of the airways caused by irritants or 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 asthma. Again this stresses the need for adding anti-inflammatory medications if bronchodilator therapy is required often to control symptoms.

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

There are steroidal and non-steroidal anti-inflammatory drugs. The most common ones include:

Steroids

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

Non-Steroidal

sodium cromoglycate (Intal®)
nedocromil (Tilade®)

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 implies that they are not suitable when there is an urgent requirement of a striking effect.

A stepwise approach to the treatment of asthma involves the introduction or change in anti-inflammatory medication.
If asthma symptoms become worse, it is essential to increase the anti-inflammatory medications in order to regain control. As control is achieved and the patient remains symptom-free over a period of time (as specified by the physician), a decrease in 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 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 are Intal® and Tilade®. They are non-steroidal and again, are used to reduce 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
- similar to Intal®
- requires 3-4 weeks to be effective
- has a bad taste
- fewer doses/canister; therefore, you may need more than one canister per month.
ketotifen (Zaditen®)
- used for mild asthma
- maybe useful for asthmatics who also have hay fever
- helps to reverse the 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 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 colds. 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: