What is the treatment approach for autoimmune encephalitis?

Treatment Approach for Autoimmune Encephalitis

First-line immunotherapy with corticosteroids, specifically intravenous methylprednisolone (IVMP) 1g daily for 3-5 days followed by oral prednisone taper, is the standard initial treatment for autoimmune encephalitis. 1

First-Line Therapy Options

Initial Treatment

• Corticosteroids:

  • IV methylprednisolone 1g daily for 3-5 days
  • Followed by oral prednisone taper (starting at 1 mg/kg/day, not exceeding 80 mg/day)
  • Preferred by 84% of experts for general AE presentations 2

• Combination therapy should be considered from the outset for severe presentations:

  • Steroids plus IVIG
  • Steroids plus plasma exchange (PLEX)
  • Particularly important for NMDAR-antibody encephalitis, status epilepticus, or severe dysautonomia 1

• IVIG (Intravenous Immunoglobulin):

  • Dosing: 2g/kg divided over 2-5 days
  • Consider as first choice in patients with high thromboembolic risk or severe hyponatremia 1

• PLEX (Plasma Exchange):

  • Typically 5-7 exchanges over 10-14 days
  • May be particularly effective in refractory cases
  • Limitations include increased bleeding risk, volume shifts, and need for central line placement 1

Second-Line Therapy

When to Escalate Treatment

• 32% of experts recommend adding second-line therapy if no response to one first-line agent
• 50% recommend adding second-line therapy if no response to more than one first-line agent
• Only 15% recommend using second-line agents in all patients 2

Second-Line Agent Options

• Rituximab:

  • Preferred second-line agent by 80% of experts 2
  • Dosing options:
    • 375 mg/m² weekly for 4 weeks, OR
    • Two 1000 mg doses 2 weeks apart 1
  • Particularly effective for antibody-mediated autoimmunity
  • Early initiation in patients who fail first-line treatment significantly improves neurological outcomes and reduces relapse rates 1

• Cyclophosphamide:

  • Preferred by only 10% of experts for unknown antibody cases 2
  • Dosing: 600-1000 mg/m²
  • More commonly used for cell-mediated autoimmunity 1

Maintenance Therapy

After acute treatment, bridging therapy should be initiated:

• Gradual oral prednisone taper (most popular choice by 38% of experts) 3
• Monthly IVIG
• Monthly IV methylprednisolone 1

For longer-term maintenance:

• Rituximab (preferred by 46% of experts) 3
• Consider mycophenolate mofetil or azathioprine for patients who respond to steroids 1
• A 6-month course of IVIG may provide adequate immunomodulation during rituximab treatment 1

Tumor Screening and Management

• Comprehensive oncological screening is essential, particularly with certain antibody types:

  • CT scans of chest, abdomen, and pelvis with contrast (or MRI when CT is contraindicated)
  • Additional tests based on clinical presentation: mammography, pelvic ultrasound, FDG-PET total body scan 1

• If a tumor is identified (particularly ovarian teratoma), surgical removal should be performed promptly 1

Treatment Considerations by Antibody Type

• NMDAR-IgG encephalitis: 63% of experts recommend corticosteroids alone or combined with other first-line agents 2
• Classical paraneoplastic encephalitis: 48.5% of experts recommend corticosteroids alone or combined with other first-line agents 2
• Faciobrachial dystonic seizures (often associated with LGI1 antibodies): 74% of experts recommend corticosteroids alone or combined with other first-line agents 2

Treatment for Refractory Cases

For patients who don't respond to conventional second-line therapies:

• Consider novel approaches such as tocilizumab (IL-6 inhibitor)
• Bortezomib (proteasome inhibitor) may be considered in severe cases 1

Common Pitfalls to Avoid

1. Delayed treatment initiation: Early aggressive treatment is associated with better functional outcomes and fewer relapses 4

2. Underestimation of disease severity: Be prepared to escalate therapy quickly in severe or worsening cases 1

3. Overlooking supportive care: Address seizures, dysautonomia, and other complications alongside immunotherapy 1

4. Delayed diagnosis: Presentation with primarily psychiatric symptoms can lead to misdiagnosis as primary psychiatric disorders 1

5. Delayed escalation to second-line therapy: Associated with poorer outcomes, highlighting the importance of timely intervention 1