[AUTOIMMUNE ENCEPHALITIS: A BRIDGE BETWEEN NEUROLOGY AND PSYCHIATRY]

Autoimmune encephalitis (AIE) usually manifests as an acute illness with psychosis, seizures and an amnestic disorder, although the clinical spectrum extends beyond this triad. The discovery of novel cell surface antibodies and antibodies directed at ion channels has revolutionized our understanding of the pathophysiology of the disease and the diagnostic tools at hand. Early diagnosis is crucial to initiation of treatment early in the disease course, which ameliorates the neurological outcome.

To delineate the clinical, imaging and laboratory characteristics of patients with AIE, as reflected in the cohort of limbic encephalitis patients treated in our department.

Patients diagnosed with AIE in our department in 2008-2018 were included in this retrospective study. All patients met the criteria for clinically probable or definite AIE, based on their clinical, laboratory and imaging findings, and the identification of causative autoantibodies.

A total of 27 patients with a diagnosis of AIE were diagnosed and treated in our department in 2008-2018; 74% had an amnestic disorder and 70% developed seizures. Psychosis was observed in 37%, though 63% showed behavioral changes; 59% had clinically relevant autoantibodies in their cerebrospinal fluid (CSF). Approximately half had pathologic brain imaging (59%) and only 33% had CSF pleocytosis. Despite immunosuppressive treatment, residual neurologic deficits were seen in the majority of the patients.

The diagnosis of AIE relies mainly on the clinical presentation, with normal ancillary studies in many cases. Thus, high clinical suspicion and prompt initiation of treatment despite lack of objective evidence of the diagnosis are necessary to limit the neurological sequela. Moreover, high awareness of AIE may allow appropriate workup and diagnosis in atypical cases.