Autoimmune Enchalopathy

• disease which produce antibodies against neuronal cell surface proteins
• sometimes responds to immunoglobulins

Types of Autoimmune Encephalopathy

• possible autoimmune encephalitis
• probable antibody negative encephalitis
• definite antibody positive encephalitis

Anti N-methyl D-Aspartate Receptor Encephalitis

• 2nd most common autoimmune encephalopathy
• can occur at any age, but most common in pediatric age groups

Clinical features

• Psychiatric manifestations (initial)
  • anxiety
  • agitation
  • delusion
  • bizarre behavior
  • labile mood
  • catatonia
  • memory deficit
  • aggression
  • sleep disturbance
• Additional manifestations (in few weeks)
  • decreased level of consciousness
  • seizures
  • oral dyskinesia
  • choreo-athetoid movement
  • autonomic instability
    • bradycardia
    • fluctuation of blood pressure

Labs

• MRI
  • non specific cortical and sub-cortical T2 flair
  • if white matter changes predominant - suspect overlapping demyelinating syndrome
• CSF
  • moderate pleocytosis
  • oligoclonal bands
  • NMDAR antibodies
• EEG
  • focal or diffuse slowing of activity in delta and theta ranges
  • Extreme delta brush - characterized by beta-delta complexes
• association with tumor (teratoma) in 40% of female older than 12
• Association with HSV1
• doubtful association with mycoplasma, HHV 6, enterovirus, COVID 19 and Japanese Encephalitis

Treatment

• Tumor removal and Immunotherapy
  • Immunotherapy
    • corticosteroids
    • IVIG
    • plasma exchange
    • Rituximab
• 80% fully recover
• 15% relapse
• 5% mortality