The epidemiology of atypical chronic lung disease in extremely low birth weight infants

To determine the incidence and associated complications of atypical chronic lung disease (ACLD) in extremely low birth weight infants.

All infants born at Johns Hopkins Hospital between 1996 and 2001, with birthweight <1000 g, gestational age <31 weeks, no major anomalies or genetic syndromes, and living at least 21 days were eligible for inclusion. Data pertaining to demographics, hospital course, diagnosis of atypical chronic lung disease, patterns of surfactant use, complications of prematurity and severity of lung disease were collected.

Using inclusion criteria, 215 eligible infants were identified, of which 185 had hospital charts available for review. Twenty-eight infants (15%) met the criteria for atypical chronic lung disease. Of the remaining 157 infants, 57 patients met the criteria for mild bronchopulmonary dysplasia (BPD) (supplemental oxygen requirement at 28 days of life), 38 patients had moderate/severe BPD (supplemental oxygen requirement at both 28 days of life and 36 weeks post-menstrual age), and 38 infants did not have chronic lung disease. Infants with ACLD had much higher rates of sepsis (46%) and pneumothorax (18%) than infants in the comparison groups.

Infants with respiratory distress syndrome in the first week of life, which initially resolves are still at risk for an atypical form of chronic lung disease. The prolonged respiratory support they require as a result of this type of lung disease increases their risk for complications of prematurity, which may outlast their lung disease. We speculate that inflammation secondary to infection acquired shortly after birth may be an important step in the pathogenesis of ACLD.