Autoimmune limbic encephalitis or syphilitic encephalopathy? Differential diagnostic difficulties (clinical cases, literature review)

The article analyzes clinical cases of two patients with a clinical picture of acute development of memory loss, psychiatric manifestation, seizures in combination with non-structural hyperintensity from the hippocampal region on MRI of the brain, laboratory serological positivity in non-treponemal and treponemal tests and signs of intrathecal immunoreactivity with a preliminary diagnosis of limbic encephalitis. The diagnostic difficulties in establishing a final diagnosis are emphasized and attention is focused on the completeness of the examination. Clinical, instrumental and laboratory features of late neurosyphilis in the form of syphilitic encephalopathy and limbic encephalitis, which have similar manifestations, are considered. The increase in the frequency of false diagnosis of autoimmune encephalitis determines the importance of a demanding attitude to differential clinical and paraclinical studies that help in determining the pathogenesis of these complex pathologies.