Asthma is a lung disease characterized by airway obstruction, inflammation, and hyper-responsiveness to environmental factors or “triggers”. In healthy individuals, the lungs have normal anatomy with clear and open airways and air sacs that allow easy flow of air out of the lungs. In contrast, in asthma patients, the lung anatomy is changed. When irritated, the airways can narrow and obstruct breathing, resulting in asthma symptoms. The airway walls are thick and swollen and increased mucus secretion causes blockage or obstruction of air flow. In some cases, breathing becomes painful and doctors usually describe it as an “asthma attack”.
When a person has asthma, he or she may experience the following symptoms:
- chronic (regular) cough;
- shortness of breath;
- wheezing; and/or,
- a feeling of tightness in the chest.
If an individual suspects that he or she might have asthma, a physician will evaluate his/her medical history and then perform a series of lung-function tests.
In the Canadian Asthma Consensus Guidelines, asthma is classified into categories of severity based on the treatment needed to obtain control.
|
Asthma Severity |
Symptoms |
Treatment Required |
| Very Mild |
Mild-infrequent |
None, or inhaled short-acting beta-agonist, rarely |
| Mild |
Well-controlled |
Short-acting beta-agonist (occasionally) and low-does inhaled glucocorticosteriod |
| Moderate |
Well-controlled |
Short-acting beta-agonist and low to moderate doses of inhaled glucocorticosteriod with or without additional therapy |
| Severe |
Well-controlled |
Short-acting beta-agonist and high doses of inhaled glucocorticosteriod and additional therapy |
| Very Severe |
May be controlled or not well-controlled |
Short-acting beta-agonist and high doses of inhaled glucocorticosteriod and additional therapy and oral glucocorticosteriod |
Asthma control should be assessed at each visit and according to the Canadian Asthma Consensus Guidelines, the following criteria should be used to assess asthma