Spanish multicentre study on morbidity and pathogenicity of tracheal bronchus in children.

Tracheal bronchus (TRB) has been generally considered an anatomical variant of the tracheobronchial tree without a precise pathological effect. Its prevalence is estimated to be between 0.2% to 3% of all children undergoing bronchoscopy and scientific information has been limited to case reports or small case series. Our working hypothesis was that TRB could trigger by itself recurrent or persistent respiratory symptoms. The objective of this retrospective and multicentre study of children with a diagnosis of TRB, coming from the main paediatric pulmonology units of Spain, was to determine the anatomical and clinical characteristics, including comorbidities, of TRB in childhood and their impact in the patients' clinical outcomes. One hundred thirty-three patients from 13 institutions were included in the study. Mean diagnostic age was 3.4 years and flexible bronchoscopy was the initial diagnostic method in 85% of cases. All TRB were located on the right wall of the trachea: 76% in the lower third and 24% in the carina. The most common clinical manifestations were obstructive bronchitis (53.3%) and recurrent pneumonia (46.6%), usually affecting the right upper lobe. Regarding associated anomalies, 33% had tracheomalacia, 32% congenital cardiovascular malformations, 28% gastroesophageal reflux, 22.5% congenital tracheal stenosis, and 8.3% Down syndrome. This series appears to be the most extensive published to date addressing this topic and, according to our data, TRB does not appear to be a mere incidental finding but is more likely linked to a wide range of congenital anomalies and contributes by itself to the recurrent respiratory symptomatology that these children exhibit.