Background and Aims Neonatal HSV encephalitis is well described and known to cause morbidity. However, there is no consensus regarding its optimal treatment, especially around using suppressive oral therapy after intravenous acyclovir. We aim to discuss treatment controversies and review possible neurodevelopmental outcomes in such cases.

Methods We report a case of vertically transmitted neonatal HSV-1 encephalitis and review existing literature on available treatment options (PubMed, EMBASE).

Results Our patient became pyrexial (39.0C) and lethargic on day 7 of life. Investigations revealed a raised CRP (80mg/l) and CSF pleocytosis (WCC-26/mm³, 90% lymphocytes) with normal CSF biochemistry. IV antibiotics were empirically started. After developing encephalopathy and seizures on day 2 of illness, IV acyclovir was added. CSF PCR was positive for HSV-1. EEG showed multifocal irritability/excitability and asymmetrical temporal lobe activities. MRI showed low signal intensity on the ADC map in the medial temporal lobe cortices bilaterally and the right inferior frontal cortex.

21 days of IV acyclovir were completed, following which a repeat CSF sample was negative for HSV-1 PCR. IV antivirals were substituted with oral acyclovir at 1500mg/m²/dose BD for twelve months.

Conclusions Literature review reveals controversies in treatment. Repeating HSV PCR at the end of IV treatment is not universally supported. Regarding suppressive oral acyclovir, some studies support doses of 1000–1740mg/m²/dose BD while others favour a 300mg/m²/dose TDS regime. Its optimal duration (6months, 12months or longer) is unclear. Neurodevelopmental outcomes mostly depend on the severity of the initial insult; Evidence that different suppressive treatments influence outcomes is poor.