Treatment of Viral Cerebellitis with Acyclovir
No specific antiviral treatment with acyclovir is needed for viral cerebellitis, as the condition is self-limiting and resolves spontaneously within one to three weeks. 1, 2
Why Acyclovir is Not Indicated
The pathophysiology of viral cerebellitis fundamentally differs from viral encephalitis:
- The primary disease mechanism is immune-mediated demyelination rather than direct viral cytopathology, making antiviral therapy ineffective at addressing the underlying process 1, 2
- The self-limiting nature of cerebellitis (resolving in 1-3 weeks) does not warrant antiviral intervention 1, 2
- Initiating acyclovir for isolated cerebellitis wastes resources and exposes patients to unnecessary renal toxicity risk 2
Appropriate Management Strategy
Supportive care is the mainstay of treatment:
- Monitor for complications, particularly cerebellar swelling and declining level of consciousness 2
- High-dose corticosteroids may be needed for severe presentations with significant cerebellar swelling 2
- Patients with falling level of consciousness require urgent ICU assessment for airway protection and management of raised intracranial pressure 1, 2
Critical Distinction: When Acyclovir IS Indicated
You must differentiate cerebellitis from encephalitis or vasculopathy, as these DO require acyclovir:
VZV Encephalitis (NOT cerebellitis):
- Intravenous acyclovir 10-15 mg/kg three times daily for up to 14 days 1, 2
- Children aged 3 months-12 years: standard dosing; children >12 years: 10-15 mg/kg three times daily 1
- Consider short course of corticosteroids (60-80 mg prednisolone daily for 3-5 days) alongside acyclovir 1
VZV Vasculopathy (stroke-like presentation):
- Both acyclovir AND corticosteroids are strongly indicated due to the inflammatory vasculitic component 1, 2
HSV Encephalitis:
- Intravenous acyclovir 10 mg/kg three times daily is the standard treatment 3, 4
- This is FDA-approved for herpes simplex encephalitis 3
Common Pitfalls to Avoid
Do not confuse cerebellitis with encephalitis:
- Cerebellitis presents with isolated cerebellar signs (ataxia, dysmetria, nystagmus) without altered consciousness 2
- Encephalitis involves altered mental status, behavioral changes, or focal neurological deficits beyond cerebellar dysfunction 1
Do not start acyclovir empirically for isolated cerebellar symptoms:
- This exposes patients to nephrotoxicity without therapeutic benefit 2, 5
- Acyclovir requires dose adjustment for renal impairment and frequent monitoring 3
Ensure access to neurological specialist opinion within 24 hours if diagnostic uncertainty exists between cerebellitis and encephalitis 1, 2