What is the treatment for varicella encephalitis?

Treatment for Varicella Encephalitis

For varicella zoster virus (VZV) encephalitis, intravenous aciclovir at a dose of 10-15 mg/kg three times daily for 14-21 days is the recommended treatment, with consideration of adjunctive corticosteroids if there is evidence of vasculopathy. 1

Treatment Algorithm

First-line Treatment

• Adults and children >12 years:

  • Intravenous aciclovir 10-15 mg/kg every 8 hours 2, 1
  • Higher dose (15 mg/kg) is often preferred because VZV is less sensitive to aciclovir than HSV 2, 1

• Children 3 months-12 years:

  • Intravenous aciclovir 500 mg/m² every 8 hours 2

• Treatment duration: 14-21 days 1

Dose Adjustment

• Reduce aciclovir dose in patients with pre-existing renal impairment 2, 1
• Maintain adequate hydration and monitor renal function throughout treatment 3, 4

Adjunctive Therapy

• For VZV vasculopathy (stroke-like presentation):
  • Add corticosteroids (prednisolone 60-80 mg daily for 3-5 days) 2, 1
  • The inflammatory nature of vasculitic lesions provides rationale for steroid use 2

Special Considerations

• Immunocompromised patients: May require prolonged courses of IV aciclovir 2, 1
• No specific treatment needed for VZV cerebellitis as it's usually self-limiting and thought to be immune-mediated rather than due to viral cytopathology 2

Management Setting and Monitoring

• Patients with suspected encephalitis should have access to immediate neurological specialist opinion 2

• Transfer to a neurological unit is recommended if:

  • Diagnosis is not rapidly established
  • Patient fails to improve with therapy
  • Transfer should occur within 24 hours of being requested 2

• Patients with declining consciousness require urgent ICU assessment for:

  • Airway protection and ventilatory support
  • Management of raised intracranial pressure
  • Optimization of cerebral perfusion pressure
  • Correction of electrolyte imbalances 2

Diagnostic Considerations

• CSF PCR results should be available within 24-48 hours of lumbar puncture 2
• Access to neuroimaging (MRI preferred) and neurophysiology (EEG) is essential 2

Outcomes and Prognosis

• Prompt recognition and treatment are essential to improve outcomes 1
• Risk factors for unfavorable outcomes include advanced age, presence of cerebral vasculitis, and reduced Glasgow Coma Scale score 5
• In a Danish cohort study, unfavorable outcomes were observed in 69% of patients at discharge, with mortality rates of 4% in-hospital, 9% at 1 month, and 11% at 3 months 5

Common Pitfalls to Avoid

• Delayed diagnosis: VZV encephalitis occurs primarily in elderly or immunocompromised patients and diagnosis is often delayed 5
• Inadequate dosing: Using standard HSV doses may be insufficient as VZV is less sensitive to aciclovir 2, 3
• Failure to monitor renal function: Crystalluria and elevated serum creatinine can occur, especially with bolus administration 4
• Missing vasculopathy: Failure to recognize and treat the vasculitic component with corticosteroids when indicated 2, 1