Complicated features in a young child with influenza B virus pneumonia and co-infection with Stenotrophomonas maltophilia.

A 3.5-year-old child with influenza B virus pneumonia developed pneumomediastinum and subcutaneous emphysema on the 3rd day of illness. Bronchoscopy demonstrated obstruction of the left main bronchus by mucopurulent sputum. Culture of the broncho-alveolar lavage yielded Stenotrophomonas maltophilia. After the respiratory complications resolved (11 days), the patient developed neurological symptoms and was diagnosed as acute disseminated encephalomyelitis (ADEM). Stenotrophomonas maltophilia was probably a factor in the development of pneumomediastinum. To our knowledge, this is the first case report of influenza virus infection with Stenotrophomonas maltophilia co-infection associated with spontaneous pneumomediastinum.