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.