Objective To identify perinatal factors associated with multiple large cysts on chest computed tomography (CT) in extremely premature infants with chronic lung disease (CLD).
Methods A case-control study of 87 infants with CLD who were ≤28 weeks’ gestation, admitted between 2005 and 2010, and underwent chest CT. CLD was defined as the need for supplemental oxygen at 36 weeks’ postmenstrual age (PMA). A chest CT was performed at between 36 and 44 weeks’ PMA. Nine infants had multiple large cysts (≥5mm) throughout the lung fields on chest CT (MLC group), and 78 had no or a few localized large cysts on chest CT (controls). Perinatal factors including placental histology was were compared between the groups.
Results The incidence of premature rupture of the membranes (PROM) and histological chorioamnionitis (HC) was significantly higher in the MLC group than in controls. Significantly more infants in the MLC group had an elevated level of serum IgM (≥30 mg/dl) at birth than in controls. The severity of respiratory distress syndrome (RDS) was significantly reduced in the MLC group compared with controls.
Conclusions The presence of multiple large cysts on chest CT is associated with an increased incidence of PROM and HC, elevated levels of serum IgM and reduced severity of RDS in extremely premature infants with CLD. These findings suggest that the presence of chronic intrauterine inflammation and the acceleration of fetal lung maturation may play important role in the formation of large cysts in the developing lung.