Postviral autoimmune encephalitis: manifestations in children and adults.

PURPOSE OF REVIEW: Autoimmune encephalitis is an increasingly recognized neuropsychiatric condition seen in patients of all ages. Herpes virus infections of the brain can antedate the development of pathogenic autoantibodies against N-methyl-D-aspartate receptors and further neuronal surface proteins, leading to neuronal dysfunction and relapsing symptoms. This review will recapitulate the recent scientific progress, clinical manifestations in children and adults, therapeutic options, and etiological concepts on how autoimmunity develops.

RECENT FINDINGS: Postviral autoimmune encephalitis has been established as disease mechanism after herpes simplex virus encephalitis. Relapsing symptoms in the absence of virus occur in up to 20% of cases. The clinical presentation is relatively stereotyped in children, consisting of choreoathetosis and reduced levels of consciousness. Adults commonly present with psychiatric abnormalities and cognitive changes. Virus-induced antibody generation seems to be a widespread mechanism not confined to Herpesviridae and N-methyl-D-aspartate receptor antibodies SUMMARY: The presence of prolonged, atypical, or relapsing symptoms after virus encephalitis must be actively determined, requiring early follow-up visits of patients, and should always prompt the search for underlying autoantibodies. Relapsing symptoms can markedly improve with immunotherapy, thus treatment, including corticosteroids, plasma separation, immunoglobulins, and rituximab is usually recommended, even if no specific antibody was detected.