Authors: Lauren Nicole Schulz, MD
Proposed etiologies of enlarged subarachnoid spaces (ESS) in infants include immaturity of arachnoid villi, impaired cerebrospinal fluid absorption and elevated venous pressures. ESS in premature infants on mechanical ventilation due to bronchopulmonary dysplasia (BPD) is common at our institution but is not well characterized in the literature. This study sought to identify the prevalence of ESS in premature infants with moderate/severe BPD, and to identify associated factors.Methods: We conducted a retrospective review of patients with prematurity and moderate/severe BPD admitted to the neonatal intensive care unit (NICU) (surgically treated post-hemorrhagic hydrocephalus excluded). The presence of ESS was determined by reviewing imaging reports. Sociodemographic characteristics, BPD severity, additional imaging findings (ventriculomegaly, periventricular leukomalacia, brain matter loss), head circumference (HC) trends, tracheostomy status and survival status were analyzed for relationships with ESS status.
ESS was seen in 44% of 261 included patients. Demographics were similar between those with ESS and those without (59% vs. 66% white, and 62% vs. 60% male, respectively). Significant associations were found between presence of ESS and increasing HC (OR 2.41, 95% CI 1.46-3.99, p < 0.001), ventriculomegaly (OR 11.83, 95% CI 6.10-22.95, p < 0.001), macrocephaly (OR 6.97, 95% CI 2.30-21.14, p < 0.001) and tracheostomy placement (OR 7.17, 95% CI 3.39-5.18, p < 0.001). Survival was significantly higher among patients without ESS (OR 0.05, 95% CI 0.007-0.420, p < 0.001). A trend was seen between presence of ESS and worse severity of BPD (p 0.054). CSF diversion was rare, with 1 shunt in each group.
These findings suggest an increased prevalence of ESS within premature BPD infants compared to the general population. Despite findings of increased HC and ventriculomegaly, these premature infants rarely require surgical intervention. The possible association with severe BPD raises the hypothesis that the management strategies (type and duration of mechanical ventilation) may be contributing factors.