[Changes in respiratory and peripheral muscle function in asthmatic children: effects of inhaled corticoids].

INTRODUCTION: Asthma is the most common chronic disease in children and adolescents. The intermittent mechanical overloads during crises can lead to functional changes in the respiratory muscles, which experience adaptation phenomena. This article attempts to evaluate the respiratory and peripheral muscle state in asthmatic children who receive inhaled corticoids, and to find out if there is an association between muscle function and respiratory function.

PATIENTS AND METHODS: The study involved 12 children over 7-years old with asthma and treated with inhaled corticoids for at least 2 years at intermediate doses (budesonide >or=400 microg, or fluticasone >or=200 microg) and 7 healthy control children paired by age. The following were determined: forced spirometry, static lung volumes, airway resistance, maximum inspiratory and expiratory pressures, peripheral musculo-skeletal function, and body composition using bioimpedance measurements.

RESULTS: The anthropometric, nutritional variables and peripheral muscle function were similar in both groups. The asthmatic children showed signs of air trapping, lung hyperinflation, and higher maximum inspiratory pressure values.

CONCLUSIONS: No evidence was found that continuous high doses of inhaled steroids lead to a deterioration in respiratory or peripheral muscle function in asthmatic children. On the other hand, signs were found of respiratory muscle adaptation to the long-term overload of persistent asthma. The so-called "training effect" seems to be limited only to the inspiratory muscles.