Steroid Treatment for Nystagmus in Encephalitis
Steroids should be initiated for new onset nystagmus in encephalitis, particularly when it is suspected to be autoimmune in etiology, but they are not routinely recommended for viral encephalitis unless there is clinical deterioration or evidence of significant cerebral edema. 1, 2
Treatment Algorithm for Nystagmus in Encephalitis
Step 1: Determine the Type of Encephalitis
- Autoimmune encephalitis: Start high-dose corticosteroids immediately
- Viral encephalitis: Consider antiviral therapy first, with steroids reserved for specific situations
Step 2: For Suspected Autoimmune Encephalitis
- Begin high-dose corticosteroids (intravenous methylprednisolone 1g daily for 3-5 days) 1, 2
- Consider combination therapy with IVIG or plasma exchange (PLEX) for severe presentations 1
- Look for specific antibodies (NMDAR, VGKC complex) to guide treatment 1
Step 3: For Viral Encephalitis
- HSV encephalitis: Steroids are not routinely recommended 1, 2
- VZV encephalitis: Consider steroids if there is evidence of vasculitis or vasculopathy 1
- For deteriorating patients: Add steroids if clinical deterioration occurs despite appropriate antiviral therapy 3
Evidence Analysis
Autoimmune Encephalitis
The strongest evidence supports early immunotherapy for autoimmune encephalitis. According to the 2021 guidelines, once infection is ruled out, acute immunotherapy with high-dose corticosteroids should be initiated 1. This is particularly important for conditions like VGKC complex or NMDA receptor antibody-associated encephalitis, where early immune suppression results in improved outcomes 1.
Viral Encephalitis
For viral encephalitis, the evidence is more nuanced:
HSV encephalitis: The 2012 British Neurologists guidelines state that "corticosteroids should not be used routinely in patients with HSV encephalitis" 1. However, they may have a role under specialist supervision, particularly in patients with marked cerebral edema or raised intracranial pressure.
VZV encephalitis: There is stronger support for steroids when there is a vasculitic component 1.
Recent evidence: A 2023 systematic review and meta-analysis could not demonstrate a benefit of steroid treatment on survival in viral encephalitis 4. However, case reports suggest that high-dose methylprednisolone can lead to remarkable improvement in deteriorating patients with viral encephalitis 3, 5.
Special Considerations for Nystagmus
Nystagmus in encephalitis may represent:
- Direct inflammatory involvement of vestibular pathways
- Increased intracranial pressure
- Brainstem or cerebellar involvement
When nystagmus is associated with cerebellar involvement in VZV infection, specific treatment may not be needed as the condition is often self-limiting 1. However, when nystagmus is part of a broader encephalitic picture with clinical deterioration, steroids may be beneficial.
Potential Risks and Monitoring
- Steroids could theoretically facilitate viral replication in viral encephalitis 1
- Monitor for steroid-induced side effects, though these are reported to be scarce 4
- Regular neurological assessment to evaluate response
- Consider repeating neuroimaging to assess for improvement in cerebral edema
Conclusion
For new onset nystagmus in encephalitis, the decision to start steroids should be guided by the suspected etiology:
- For autoimmune encephalitis: Start steroids promptly
- For viral encephalitis: Reserve steroids for cases with clinical deterioration, significant cerebral edema, or evidence of vasculopathy
The timing of steroid administration may be critical, with earlier treatment (within 5 days of symptom onset) potentially offering better outcomes 5.