Neurosyphilis Mimicking Autoimmune Encephalitis: A Case Report and Review of the Literature

Neurosyphilis may imitate a wide range of neurological and psychiatric diseases, including autoimmune encephalitis. To avoid further cognitive decline and morbidity, early recognition and adequate treatment are of particular importance in both neurosyphilis and autoimmune encephalitis. In case of a strong clinical suspicion of a diagnosis of autoimmune encephalitis, guidelines recommend initiating immunotherapy even in the absence of immunological confirmation. Here, a case of neurosyphilis is reported in which the potential overlap in clinical presentation of autoimmune encephalitis and parenchymatous neurosyphilis is discussed. The here reported data suggest that, in cases presenting with new onset focal epilepsy, slowing of electroencephalographic activity over the temporal regions and magnetic resonance imaging suggestive of swelling of the amygdala, neurosyphilis should be excluded prior to initiation of immunotherapy for suspected autoimmune encephalitis.