Varicella zoster encephalitis

The diagnosis of varicella zoster encephalitis is confirmed when viral DNA is detected on polymerase chain reaction (PCR) of the CSF. Treat all patients with suspected varicella zoster encephalitis – do not delay treatment while investigations are being performed.

Note: Do not delay treatment while investigations are being performed.

For adults and children 1 month or older with varicella zoster encephalitis, use:Gilden 2007 Kleinschmidt-DeMasters 2001 Solomon 2012

aciclovir intravenously, 8-hourlyaciclovir aciclovir aciclovir

adult and child older than 12 years: 10 mg/kg¹ ². For dosage adjustment in adults with kidney impairment, see aciclovir intravenous dosage adjustment

child younger than 5 years: 20 mg/kg or 500 mg/m²¹ ²

child 5 years to 12 years: 15 mg/kg or 500 mg/m²¹ ².

Duration of therapy for varicella zoster encephalitis is not well defined, but 14 to 21 days have been used – seek expert advice.Solomon 2012

For neonates with varicella zoster encephalitis, see the Australasian Society for Infectious Diseases (ASID) guidelines on the Management of perinatal infections.

In patients who are clinically improving, a switch to oral therapy may be appropriate to complete therapy – seek expert advice.

¹ In adults and children older than 12 years with varicella zoster encephalitis, higher aciclovir doses (ie up to 15 mg/kg intravenously, 8-hourly) have been used; however, given the potential for toxicity with these higher doses, their use should be reserved for when they can be supported with clinical monitoring.Return

² Aciclovir dosing in obesity is poorly defined; however, limited data support dosing based on adjusted body weight in adults and ideal body weight in children. For simplicity, some centres recommend a maximum dosing weight of 100 kg (eg 1 g for 10 mg/kg doses, 1.5 g for 15 mg/kg doses).Return