The epidemiology of tracheobronchitis in pediatric practice.

Epidemiologic characteristics of childhood tracheobronchitis occurring over a 104-month period in Chapel Hill, NC, were ascertained and compared to those of other pediatric lower respiratory illness (LRI) syndromes. Tracheobronchitis accounted for 40% of all LRI seen at the community's only pediatric practice. Tracheobronchitis incidence was highest during the first two years of life, through the ratio of tracheobronchitis incidence to total LRI incidence increased with age. A viral pathogen or Mycoplasma pneumoniae was isolated from 23% of tracheobronchitis cases; the agents most commonly isolated were parainfluenza viruses, influenza viruses, respiratory syncytial virus, and M. pneumoniae. Influenza virus, particularly type B, was isolated more commonly in tracheobronchitis than in other LRI syndromes. Over all age groups, peak incidence of tracheobronchitis, like that of pneumonia and bronchiolitis, occurred during the winter months. In school-age children, however, tracheobronchitis incidence was more likely than that of other syndromes to be elevated in late winter or early spring, when several influenza B outbreaks occurred in Chapel Hill. Available evidence suggests that risk of chronic respiratory disease is related inversely to age at which acute respiratory infection first occurs, and that a component of wheezing may not be required to confer such risk. These considerations, coupled with the high incidence of tracheobronchitis early in life, warrant further description of this syndrome and assessment of its implications.