Autoimmune Encephalitis.

Autoimmune encephalitis is a common and treatable cause of encephalitis in children and adults. Individuals present with a variety of symptoms, including altered mental status, behavioral changes, irritability, insomnia, developmental regression, seizures, dyskinetic movements, and autonomic instability. Evaluation includes electroencephalography, magnetic resonance imaging, and lumbar puncture. Once infectious and other causes are reasonably ruled out, treatment should be started empirically without waiting for antibody confirmation. Early clinical suspicion is key, as the outcome depends on early initiation of immunotherapy, including corticosteroids, intravenous immunoglobulin, and/or plasmapheresis. Severe or refractory cases require other treatments, such as rituximab, cyclophosphamide, or other immunotherapies using novel monoclonal antibodies. Psychiatry should be involved early for the management of behavioral issues. Additional considerations include management of seizures and dyskinesias. ICU admission may be required for management of hypoventilation necessitating mechanical ventilation (either intrinsic or iatrogenic, eg, from sedatives), refractory seizures, and dysautonomia. Anti-N-methyl-d-aspartate receptor and other forms of autoimmune encephalitis are less often associated with neoplasia (such as ovarian teratoma) in children compared with adults, but screening and removal of tumor if present should be performed.