RESUMO
BACKGROUND: patients with cystic fibrosis commonly have severe malnutrition and growth retardation. Among possible causes of these manifestations are low caloric intake, loss of nutrients and increased resting energy expenditure. This study was designed to assess the influence of antibiotic therapy for infectious exacerbations on resting energy expenditure in young patients with cystic fibrosis. METHODS: We studied 17 patients with cystic fibrosis (mean age, 13.6 years). All were hospitalized to receive intravenous antibiotic therapy (mean duration, 2 weeks) for acute respiratory exacerbations. At the beginning of therapy and after it ended, all patients underwent blood chemical tests, anthropometrical measures, determination of body composition by bioelectrical impedance, spirometry, and indirect calorimetry. RESULTS: Antibiotic therapy led to a significant improvement in biochemical, spirometric variables and in estimated calorimetry measurements expressed in relation to fat-free mass. These findings suggest that infective exacerbations are among the causes of increased resting energy expenditure in young patients with cystic fibrosis. CONCLUSIONS: Indirect calorimetry may prove useful in the diagnosis of infective exacerbations and in monitoring the effect of antibiotic therapy in patients with cystic fibrosis.