Treatment of Herpes Simplex Virus Infections

Introduction to Treatment Guidelines

The recommended dose of aciclovir for HSV meningitis in adults with normal renal function is 10 mg/kg intravenously every 8 hours for 14 days, as suggested by the Infectious Diseases Society of America 1, 2

For children aged 3 months to 12 years, the recommended dose is 500 mg/m² IV every 8 hours for 14-21 days, as recommended by the Pediatric Infectious Diseases Society 2
For children over 12 years, the recommended dose is 10 mg/kg IV every 8 hours for 14-21 days, as recommended by the Pediatric Infectious Diseases Society 2

For HSV encephalitis, treatment should be continued for 14-21 days due to higher morbidity and mortality, as suggested by the Infectious Diseases Society of America 1, 3, 4, 5, 6
In patients with pre-existing renal insufficiency, the dose should be reduced, and renal function should be monitored during treatment, as aciclovir can cause renal insufficiency due to crystaluria in up to 20% of patients after 4 days of IV therapy, as reported by the Infectious Diseases Society of America 2, 4
Patients with severe cases may require higher doses and longer treatment duration, as suggested by the Centers for Disease Control and Prevention 6

A lumbar puncture should be repeated at the end of treatment to confirm that it is negative for HSV by PCR, as recommended by the Infectious Diseases Society of America 2
If the lumbar puncture remains positive for HSV by PCR, aciclovir should be continued with weekly PCR testing until it is negative, as recommended by the Infectious Diseases Society of America 2
Clinical signs of meningitis, such as headache, photophobia, fever, and meningismus, should be looked for in patients, and the gold standard for confirming diagnosis is CSF PCR testing for HSV, as recommended by the Infectious Diseases Society 3, 7
CSF typically shows lymphocytic pleocytosis with mildly elevated protein and normal glucose in patients with HSV-2 meningitis 3

In cases of aciclovir resistance, foscarnet 40 mg/kg IV every 8 hours may be considered, as recommended by the Centers for Disease Control and Prevention 6
The safety of systemic acyclovir and valacyclovir in pregnancy has not been established, and cases should be reported to the registry maintained by Glaxo-Wellcome in cooperation with CDC 6
Most recurrent lymphocytic meningitis cases (78-84%) are caused by HSV-2, and valacyclovir 500 mg twice daily is not recommended for suppression of recurrent HSV-2 meningitis due to insufficient drug levels in the CSF 3

Treatment should not be delayed if there is a strong clinical suspicion of HSV encephalitis or meningitis, and aciclovir should be started empirically while awaiting diagnostic results, as recommended by the Infectious Diseases Society of America 1 and the Pediatric Infectious Diseases Society 2
The full treatment course should be completed, with 14 days for meningitis and 14-21 days for encephalitis, as recommended by the Infectious Diseases Society of America 1 and the Pediatric Infectious Diseases Society 2
For patients with established recurrent HSV-2 meningitis, oral therapy may be used for the entire course, as recommended by the CDC 3
For HSV-2 meningitis, the CDC suggests a specific treatment protocol starting with intravenous aciclovir 10 mg/kg every 8 hours until resolution of fever and headache, followed by valacyclovir 1 g three times daily to complete a 14-day course 3