Treatment for LGI1 Encephalitis
Corticosteroids are the first-line treatment for LGI1 encephalitis, with intravenous methylprednisolone (IVMP) being the recommended initial therapy. 1
First-Line Treatment Algorithm
- Begin with high-dose corticosteroids (intravenous methylprednisolone) once infection is ruled out based on CSF results 1
- Faciobrachial dystonic seizures (FBDS), a hallmark of LGI1 encephalitis, are particularly steroid-responsive 1
- Monitor for and manage hyponatremia, which is common in LGI1 encephalitis (present in ~55% of cases) 1, 2
- If there is no clinical improvement after initial steroid treatment, add IVIG or plasma exchange (PLEX) 1
Treatment Options and Efficacy
First-Line Options:
- Corticosteroids: 93% remission rate in initial treatment 2
- IVIG: 87.5% remission rate when used alone 2
- Combined steroids and IVIG: 96.7% remission rate, suggesting superior efficacy 2
- Plasma exchange (PLEX): Consider in patients with severe hyponatremia or high thromboembolic risk 1
Treatment Response:
- Early immunotherapy is crucial for better outcomes and prevention of cognitive dysfunction 1
- Faciobrachial dystonic seizures respond rapidly to immunotherapy, which may prevent progression to more widespread cognitive impairment 1
- Anti-epileptic drugs may be added to control seizures, which can benefit cognitive function 2
Second-Line Treatment
- For patients with no improvement 2-4 weeks after combined first-line therapy, consider second-line agents 1
- Rituximab is recommended for antibody-mediated autoimmunity like LGI1 encephalitis 1
- Immunosuppressants may improve outcomes in refractory cases or when relapse occurs 2
Preventing Relapse
- Maintain long-term immunotherapy as 60% of relapses occur in patients who discontinued treatment prematurely 2
- Consider bridging therapy with gradual oral prednisone taper or monthly IVIG/IVMP 1
- Early identification, clear diagnosis, and rapid treatment are essential to reduce relapse rates 2
Special Considerations
- MRI evidence of medial temporal lobe inflammation is present in approximately 60% of patients 1
- CSF changes are uncommon in LGI1 encephalitis, unlike other forms of autoimmune encephalitis 1
- Serum testing has higher sensitivity (99.8%) than CSF testing (77.4%) for LGI1 antibodies 2
- Most patients respond within a few weeks to immunotherapy with good outcomes 1
Treatment Pitfalls to Avoid
- Delaying immunotherapy while waiting for antibody test results can worsen outcomes - treatment should begin once infection is ruled out 1
- Failing to screen for underlying malignancy (although tumors are rare with LGI1-antibodies compared to other autoimmune encephalitides) 1, 2
- Premature discontinuation of immunotherapy, which increases relapse risk 2
- Inadequate management of hyponatremia, which requires careful monitoring and correction 1