[Asthma induced by exercise]

Abstract

Exercise induced-asthma (EIA) is a frequent symptom concerning about 12% of the general population and at least 90% of asthmatics. It is often the first manifestation of asthma and is underestimated both by the patient and the practitioner. The pathophysiological mechanism is dealing with thermodynamic changes of bronchial mucosa, however it is not completely elucidated. Rapid cooling of bronchial mucosa and rewarming of expired air induces bronchial hyper circulation, hyperosmolarity and mast cell infiltration with release of mediators responsible for the bronchial narrowing after exercise. The diagnosis of EIA is usually historical. The measurement of peak flow after the exercise is the easiest way to confirm the diagnostic. Provocation tests in laboratory are sometimes useful. Warm-up protocoles are insufficient to prevent EIA in athletes. The beta-2-mimetics are the first choice drugs and may be associated with nedocromil-cromolyn if necessary. Inhaled corticosteroids are effective in long term administration, but it is a treatment of third choice. When corticosteroids are necessary, "unstable" asthma should be suspected.