2342. Treatment Implications of Herpes Simplex Virus Central Nervous System Infection in Canadian Infants <90 Days Old: A Pediatric Investigators Collaborative Network on Infections in Canada (PICNIC) Study

In the pre-acyclovir era, HSV CNS infection was associated with very high morbidity and mortality. Since antiviral drugs recommended for therapy and long-term prophylaxis improve outcomes, clinicians need to be able to clinically detect young infants most likely to have HSV to facilitate early initiation of therapy. Limited data exist on outcomes of infants who require prolonged therapy and those completing prophylaxis. The objective of this study was to identify clinical and laboratory features associated with HSV CNS disease and describe outcomes following antiviral therapy and prophylaxis. Infants <90 days old with a discharge diagnosis of meningitis or encephalitis from whom a virus was identified from cerebrospinal fluid (CSF) were included. These were identified using PICNICs retrospective database of microbiologically confirmed CNS infections detected January 2013 to December 2014. Clinical features and outcomes of HSV and non-HSV infection were compared. Of the 112 cases of viral infections, HSV accounted for 8 (7%) and enterovirus for 103 (92%). Eight (100%) HSV cases and 45 (43%) non-HSV cases presented at <21 days. Four (50%) HSV cases had no pleocytosis. HSV cases were more likely to require ICU admission (P = 0.016), present with seizures (P < 0.001) and have extra-CNS disease (P < 0.001). Among infants <3 weeks of age, seizures were more likely in HSV than non-HSV cases (4 (50%) vs. 4 (8%); P = 0.013). All HSV cases received acyclovir for a median of 23 days. Two (25%) remained PCR-positive at 21 days; these were treated for 51 and 42 days, respectively, until PCR negative or death (acyclovir resistance was confirmed postmortem). Four infants received suppressive acyclovir until 6 months, one of whom developed virologically proven CNS recurrence and subsequent infantile spasms. Neurodevelopmental morbidity (4 (57%) vs. 7 (7%)) was more likely in HSV than non-HSV (P = 0.003). High levels of suspicion for viral infections must be maintained for young infants presenting with seizures in the first 3 weeks of life. CSF pleocytosis may often be absent. Resistance testing should be considered if PCR remains positive beyond 21 days. CNS recurrences may still occur beyond the recommended period of prophylaxis. All authors: No reported disclosures.