AUTHOR=Liao Haibing , Zhang Yajing , Yue Wei 

TITLE=Case Report: A Case Report of Neurosyphilis Mimicking Limbic Encephalitis

JOURNAL=Frontiers in Neurology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.862175

DOI=10.3389/fneur.2022.862175

ISSN=1664-2295

ABSTRACT=Neurosyphilis (NS) is an infection of the central nervous system caused by Treponema pallidum. It mimics various neurological and psychiatric diseases. In recent years, there have been increased NS cases that manifest as autoimmune encephalitis (AE). Therefore, the diagnose of neurosyphilis in the early stages is difficult. Here, we present a case of a NS patient who presented with anti-leucine-rich glioma inactivated 1(LGI1) encephalitis-like manifestation. The 62-year-old woman presented with acute clinical manifestations of gibberish speech, poor memory, and seizures. Brain magnetic resonance imaging (MRI) showed abnormal signals on the right medial temporal lobe. In addition, the patient had a positive serum LGI1 antibody with a titer of 1:16. Therefore, an initial diagnosis of anti-LGI1 encephalitis was made. However, further tests carried out showed positive rapid plasma reagin (RPR), and treponema pallidum particle agglutination (TPPA) tests both in the serum and the cerebrospinal fluid (CSF). Therefore, uncertainty arose as to whether the patient had both anti-LGI1 encephalitis and NS or whether the anti-LGI1 encephalitis-like manifestations were due to the NS. The patient was initiated on the recommended dose of penicillin G sodium. Following treatment, the patient reported a significant improvement in clinical symptoms, normal signals in the right temporal lobe, and a negative serum LGI1 antibody. These findings suggested that the anti-LGI1 encephalitis-like manifestations were due to the NS. This case demonstrates the importance of testing syphilis in patients with suspected AE