[Autoimmune encephalitis. A review].

Autoimmune encephalitis are one of the emergent causes of subacute changes in the level of consciousness, behavior, cognitive impairment and seizures, mainly in young people. They are a consequence of inflammation or dysfunction of parts of the brain caused by antibodies against specific brain antigens, usually located in the limbic system, resulting in clinical presentation as a limbic encephalitis. The objectives of this article are to show the clinical presentation, complementary studies and treatment of this entity, considering that the patient's prognostic depends on a high level of clinical suspicion, and on an early initiation of immunosuppressive therapy. We did a nonsystematic review of the literature on autoimmune encephalitis between 2005 and 2017. We conclude that the prevalence of autoimmune encephalitis is increasing, even surpassing infectious causes of encephalitis in developed countries. Clinical presentation includes sub-acute cognitive and behavioral impairment, with or without alterations in consciousness and seizures. Fever and inflammation of the cerebrospinal fluid are less common than in the infectious causes but psychiatric symptoms are more frequent. There are specific clinical presentations according to the particular type of antigen/antibody present, which also determines the association with cancer, constituting a paraneoplastic syndrome only in some cases. Immunosuppressive therapy has been standardized in steps, and should be initiated early to improve prognosis.