Autoimmune encephalitis: suspicion in clinical practice and mimics

Despite the existence of well-established diagnostic criteria for autoimmune encephalitis, there are diseases capable of mimicking it. This study sought to retrospectively evaluate the reasons for testing and the final diagnosis of patients admitted to a Neurology ward tested for anti-NMDAR antibodies and estimate sensitivity and specificity of current diagnostic criteria. The threshold for testing was lower than that of the prevailing diagnostic criteria, and the proportion of autoimmune encephalitis mimics was high. Searching for alternative diagnoses is of pivotal importance in cases of autoimmune encephalitis suspicion, and diagnostic criteria may need expanding so that no autoimmune encephalitis is missed.