Bilateral cystic periventricular leukomalacia in the premature infant: associated risk factors.

BACKGROUND: Bilateral cystic periventricular leukomalacia (PVL) is a major cause of neurodevelopmental delay in the premature infant. Thus, early identification of the preterm infant at highest risk for the subsequent development of this lesion is critical.
OBJECTIVES: The three objectives of this case-control study were: (1) to determine the basic characteristics of cystic PVL, (2) to assess the relationship of perinatal clinical events and PVL, and (3) to ascertain the feasibility of identifying early those preterm infants at highest risk for the development of PVL.
METHODS: The medical records and cranial ultrasound scans (HUSs) were reviewed for 632 infants weighing less than 1750 g who were admitted to the neonatal intensive care unit between January 1992 and December 1993. PVL developed in 14 infants of 1285 +/- 301 g birth weight (BW) and 29.4 +/- 1.5 weeks' gestational age (GA); severe intraventricular hemorrhage (n = 21) and intraparenchymal echodensity (n = 12) developed in 33 infants of 904 +/- 248 g BW and 26.6 +/- 1.8 weeks' GA; and 585 infants of 1315 +/- 324 g BW and 29.7 +/- 2.4 weeks' GA with normal HUS findings (n = 473) or grade I or II intraventricular hemorrhage (n = 112) served as a comparison group.
RESULTS: Cystic PVL was observed in 14 (2.3%) of 632 infants weighing less than 1750 g, more specifically, in 3.2% of infants weighing less than 1500 g. Cysts were noted from the 7th to 14th days of life in 10 infants and from the 20th to 46th days of life in 4 infants. Ten (70%) of the infants had relatively benign clinical courses, and most cases were detected by routine HUS surveillance. Over hypotension in the immediate perinatal period was noted in 3 (21%) infants; late hypotension developed in 1 additional infant. Univariate analysis indicate that two clinical indicators, prolonged rupture of membranes (PROM) and chorioamnionitis, were significant predictors of PVL. For PROM, the odds ratio estimate and the 95% confidence limit are 6.59 and 1.96 to 22.10, with a sensitivity of 28.6% and positive predictive value of 11.5%. Similar values for chorioamnionitis are 6.77 (1.77 to 25.93), with a sensitivity of 21.4% and positive predictive value of 11.5%.
CONCLUSIONS: (1) Most cases of symmetric cystic PVL occurred in infants with relatively benign clinical courses and were only detected by routine ultrasound screening. (2) Postnatal systemic hypotension seems to be an uncommon associated event. (3) Preterm infants born to mothers with PROM and/or chorioamnionitis seem to be at an increased risk for the development of PVL and should be carefully evaluated.