Key Points Question What are the most effective treatments for N -methyl- d -aspartate receptor (NMDAR) antibody encephalitis? Findings In this meta-analysis of individual patient data including 1550 cases, treatment factors at first event that were significantly associated with good functional outcome 12 months from disease onset included first-line treatment with therapeutic apheresis alone, corticosteroids in combination with intravenous immunoglobulin (IVIG), or corticosteroids in combination with IVIG and therapeutic apheresis, while lack of immunotherapy within 30 days of disease onset was significantly associated with poor outcome. Rituximab and long-term IVIG use were significantly associated with nonrelapsing disease course. Meaning Separate treatment factors are associated with functional outcomes and relapsing disease biology in those with NMDAR antibody encephalitis.

Relapsing disease after ADEM is fairly common and associated with a few potentially predictive features at initial presentation. Age-specific guidelines for ADEM diagnosis and treatment may be valuable, and vigilance for other, mostly rare, diseases is imperative.