2587. Etiology and Outcome of Acute Neonatal Infectious Encephalitis

BACKGROUND: There are very few studies on acute encephalitis with onset during the neonatal period. The objectives of this study were to investigate the etiology and salient clinical features of neonatal encephalitis. METHODS: Neonates with possible infectious encephalitis (IE) were prospectively enrolled. Inclusion criteria included encephalopathy (altered/fluctuating level of consciousness ≥24 hours) plus ≥2 of: fever/temperature instability; seizure(s); focal neurologic findings; CSF pleocytosis; EEG abnormalities consistent with encephalitis; neuroimaging abnormalities consistent with encephalitis. Neonates with a clear diagnosis of post-perinatal asphyxial encephalopathy or culture proven bacterial meningitis were excluded. Results shown as absolute numbers, proportions or medians [interquartile range] as appropriate. RESULTS: Fifty-nine neonates fulfilled the inclusion/exclusion criteria (June 2013–November 2018). Empiric acyclovir was initiated in 49 (83.1%) cases. An infectious etiology was identified in 25 (42.4%): enteroviruses (n = 15), HSV (n = 5), HHV6 (n = 2), parainfluenza 3 (n = 1), influenza A (n = 1), CMV (n = 1). A noninfectious cause was confirmed in 20 (33.9%): missed hypoxic-ischemic encephalopathy (n = 10), genetic/metabolic disorders (n = 7), ischemic/hemorrhagic stroke (n = 3). No specific etiology was identified in 14 (23.7%). Thirteen (52%) neonates with IE either died (n = 7) or suffered neurologic sequelae (n = 6). Deaths were attributable to HSV (n = 4), enteroviruses (n = 2) and HHV6 (n = 1). Neurocognitive sequelae were documented in one case each of enterovirus, HSV2, HHV6, CMV, parainfluenza 3 and influenza A. Differences between neonates with and without IE, respectively, included age in days of symptom onset (7 [6, 10] vs. 1 [0, 3]; P < 0.001), gestational age (37.0 [36.0, 39.0] vs. 38.6 [37.6, 40.0]; P = 0.045), peripheral leukocyte count (10.5 [IQR 5.9, 14.6] vs. 14.3 [IQR 10.7, 21.7]; P = 0.008) and CSF glucose (2.80 [IQR 2.3, 3.2] vs. 3.10 [2.8, 3.8]; P = 0.003). CONCLUSION: Enteroviruses and HSV are the predominant causes of neonatal IE. Outcome of neonatal IE is poor with approximately half dying or suffering neurologic sequelae. DISCLOSURES: All authors: No reported disclosures.