82 - Autoimmune Encephalitis with Antibodies to Cell Surface Antigens

Abstract

Autoimmune encephalitis with antibodies to neuronal cell surface and synaptic antigens are a group of neuropsychiatric disorders in which the associated antibodies appear to mediate the neuronal dysfunction by direct interaction with their target antigens. These antibody effects are reversible and although the process of recovery can be prolonged, patients with these syndromes often have full or substantial recovery with treatment. These disorders can occur with and without a cancer association and while they affect individuals of all ages, some syndromes preferentially affect young adults and children. These disorders are therefore different from the paraneoplastic encephalitis in which the antibodies target intracellular proteins, and T-cell mechanisms appear to play a predominant role in mediating the neuronal dysfunction that is often irreversible. The diagnosis of autoimmune encephalitis can be straightforward for patients who present with a characteristic syndrome but may be challenging when one or a few symptoms predominate. In some, but not all cases supporting findings such as inflammatory signs in cerebrospinal fluid or the presence of oligoclonal bands can be useful. Abnormalities on magnetic resonance imaging fluid-attenuated inversion recovery sequences are more commonly seen in some syndromes than others. The presence of the specific antineuronal cell surface/synaptic antibodies in cerebrospinal fluid and serum confirms the diagnosis, but treatment should not be delayed while antibody results are pending as this can negatively affect the outcome. In general, autoimmune encephalitis should be included in the differential diagnosis of any patient, especially if young, with a rapidly progressive encephalopathy of unclear origin and in a patient with a past history of encephalitis or relapsing encephalopathy.