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In CNS infections, is there a need to complete acyclovir for 21 days or we can stop it on 14th day after case improvement?
Hossam Elgnainy Selected answer as best
For pediatric CNS infections (encephalitis/meningitis) caused by HSV, here are the key points:
Duration of IV acyclovir therapy
- Neonates (≤28 days old):
- HSV CNS disease: 21 days is the standard recommendation (AAP Red Book, IDSA, Nelson Pediatrics).
- Even if the baby looks clinically improved before 21 days, treatment should continue to complete the full course.
- A repeat CSF HSV PCR at day 21 is recommended. If still positive → continue acyclovir until a negative result is achieved.
- Older infants/children/adolescents:
- HSV encephalitis: usually treated with 14–21 days of IV acyclovir.
- Most guidelines (IDSA, AAP, UpToDate) recommend at least 14 days, but many experts prefer 21 days to reduce relapse risk.
Stopping at day 14?
- Not recommended in neonates → must complete 21 days minimum.
- In older children, some centers stop at 14 days if clinical and radiologic improvement is clear, and HSV PCR from CSF becomes negative.
- However, the safer approach is 21 days, especially if initial disease was severe, as relapses are documented after shorter courses.
Hossam Elgnainy Selected answer as best