Is secondary tracheomalacia associated with persistent lower respiratory tract inflammation and subclinical infection?

Background. In secondary tracheomalacia due to mediastinal vascular anomalies one of the most prevalent symptom is recurrent lower respiratory tract (LRT) infections, related to defective airway clearance. Whether this condition could result in persistent LRT inflammation and subclinical infection is not known. Patients and methods. Children with tracheomalacia due to mediastinal vascular anomalies, recurrent (>3/y) LRT infections were evaluated while in stable condition. Computed tomography (CT) scan and bronchoscopy with bronchoalveolar lavage (BAL) were performed. Results. 31 children were included in the study: 21 with aberrant innominate artery (AIA), 4 with right aortic arch (RAA) and 1 with double aortic arch (DAA) and 5 with AIA associated with RAA. Cytological evaluation of BAL fluid showed increased neutrophil percentages and normal lymphocyte and eosinophil proportions. Microorganism growth was detected in 35.5% of BAL samples, with a bacterial load >105 colony-forming-units (CFU)/mL only in 10,2% of them. Most isolates were positive for Haemophilus influenzae, followed by Streptococcus pneumoniae, Group A β-hemolytic streptococci and Moraxella catarrhalis. Chest CT scan demonstrated the presence of bronchiectasis in 13% of the children, of which only one had a positive BAL culture for Haemophilus influenzae. Conclusions. Only in a small subgroup of children, persistent neutrophilic alveolitis was associated with a significant bacterial load and the presence of bronchiectasis. Because most pathogens detected in BAL samples cultures can produce biofilms, caution should be used in inappropriate antibiotic prescription in these patients that, chiefly in those with bronchiectasis, in which chest physiotherapy can be of great benefit.