|
| The 30 per cent of adults with more serious asthma
symptoms account for 87 per cent of the total costs incurred
each year. |
|
|
| Does your child have EIA? |
|
Exercise induced asthma, also known as EIA, is a condition in which physical activity or exercise triggers airway narrowing in children with asthma. A child previously diagnosed with asthma who has symptoms of cough, wheeze, and shortness of breath during or shortly after vigorous physical activity or exercize almost certainly has EIA. Some children do not have the typical symptoms but instead complain of cough, chest tightness, or difficutly breathing air in. If a diagnosis of asthma has not already been made, the diagnosis of EIA may be delayed and the child denied the appropriate explanations and treatments. |
| |
| What causes EIA? |
|
The upper part of the airway, particularly the nose, is responsible for conditioning (warming and humidifying) the air that we breathe in. During rapid breathing there is an initial fall in airway temperature followed by a rise as breathing slows down. During very rapid breathing, particularly of cold, dry air, the conditioning process moves from the upper to the lower airways (bronchi). Greater movement of heat and water from the airway lining is required to fully humidify the inhaled air at body temperature. It is thought that these temperature changes lead to the development of airway obstruction although the exact mechanisms are not known. One theory is that evaporation of water from the airway lining causes the release of bronchoconstricting substances from mast cells. Another theory is that narrowing of the airways occurs from engorgement of blood vessels in the airway wall although this seems less likely. |
| |
| What kinds of activities and conditions bring on EIA? |
|
Any activities that cause increased breathing can trigger symptoms of EIA. Long distance track events, cross country running, soccer, figure skating, and hockey can be particularly troublsome in some children. Activities requiring sustained increases in breathing may be more troublesome than those that are shorter or allow for brief rest periods. Outdoor activities may be worse than indoor ones, reflecting the effects of air temperature and humidity on the airways. Activities carried out in cold, dry air are more problematic than those performed in warm, moist environments. The additional effects of air pollution can also be a problem. Keeping a diary of the pattern of symptoms can be helpful although the family's attention should not become unduly focused. |
| |
| How common is EIA? |
|
It is thought that EIA occurs in 70-90% of patients with asthma. Estimates vary because of the different methods used to make the diagnosis. Airway obstruction with exertion is not normally found in the general population but can occur in relatives of patients with asthma and in allergic indiviuals. |
| |
| Can EIA occur without other symptoms of asthma? |
|
Although EIA occasionally occurs by itself in a person who denies any other asthma symptoms, this is not common. Careful questioning often reveals symptoms, although mild, associated with some of the other asthma triggers. |
| |
|
|
|
