Are steroids needed for viral cerebellitis?

Steroids for Viral Cerebellitis

No, steroids are not routinely needed for viral cerebellitis, as the condition is self-limiting and resolves within 1-3 weeks with supportive care alone. 1, 2

Primary Management Approach

Viral cerebellitis typically requires only supportive care without specific treatment. 2 The rationale is straightforward:

• The primary pathogenic process is immune-mediated demyelination rather than direct viral cytopathology 1, 2
• The disease is self-limiting, resolving within one to three weeks in most cases 1, 2
• Antiviral treatments (like aciclovir) are not normally used and provide no benefit 1, 2

When Steroids ARE Indicated

High-dose corticosteroids should be used for severe presentations with cerebellar swelling, particularly when complicated by:

• Cerebellar edema with mass effect 2, 3
• Obstructive hydrocephalus 4, 5
• Tonsillar herniation or risk of brainstem compression 3, 4, 5
• Falling level of consciousness requiring ICU assessment 2

The evidence supporting steroids in severe cases comes from case series showing that patients with cerebellar swelling who received high-dose steroids had complete recovery, while those who did not receive steroids died or had permanent sequelae 3. A pediatric series of 15 cases treated with steroids showed no fatalities and only 27% had residual symptoms at follow-up 5.

Dosing for Severe Cases

• Dexamethasone 8 mg every 6 hours or prednisolone 60-80 mg daily for 3-5 days 1, 4, 6
• Taper over 2-4 weeks based on clinical response 6

Critical Distinction: Cerebellitis vs. Encephalitis

Do not confuse isolated cerebellitis with encephalitis—the treatments differ significantly:

• VZV cerebellitis: No antiviral treatment needed 1, 2
• VZV encephalitis: Requires IV aciclovir 10-15 mg/kg three times daily for up to 14 days, with or without corticosteroids 1
• VZV vasculopathy (stroke-like presentation): Requires both aciclovir AND corticosteroids 1

Clinical Algorithm for Decision-Making

Step 1: Confirm isolated cerebellitis

• Ataxia, dysmetria, nystagmus without altered consciousness 4, 5
• MRI showing cerebellar cortical T2 hyperintensity without encephalitis features 5

Step 2: Assess for complications requiring steroids

• Look for tonsillar herniation on imaging (present in 73% of cases) 5
• Check for obstructive hydrocephalus (present in 27% of cases) 5
• Monitor level of consciousness closely 2

Step 3: Treatment decision

• Uncomplicated cerebellitis: Supportive care only, neurological specialist opinion within 24 hours 2
• Complicated cerebellitis with swelling/herniation: High-dose steroids immediately 3, 4, 5
• Deteriorating consciousness: ICU transfer for airway protection and ICP management 2

Common Pitfalls to Avoid

• Do not initiate aciclovir for isolated cerebellitis—this wastes resources and exposes patients to unnecessary renal toxicity risk 2
• Do not assume all cerebellar presentations are benign—headache and vomiting accompanying ataxia should raise concern for cerebellitis rather than simple postinfectious cerebellar ataxia 5
• Do not delay imaging—MRI is required to diagnose cerebellitis and assess for complications 4, 5
• Do not miss the window for steroid intervention—early recognition and treatment of cerebellar swelling prevents herniation and improves outcomes 3, 6

Prognosis and Follow-up

• About one-third of patients have residual neurological deficits (ataxia, dysmetria, memory difficulties) at follow-up 5
• Follow-up MRI shows cerebellar atrophy in 75% of cases, though this does not predict clinical outcome 5
• Early diagnosis and steroid treatment in severe cases appears to reduce mortality to near zero 5