Neurosyphilis with oral‑facial‑lingual dyskinesia: A case report.

The present study describes the case of a 52-year-old male patient who presented with subacute onset dysarthria and oral-facial-lingual dyskinesia, with normal blood glucose and acanthocyte levels, and no history of drug use. The patient tested negative for autoimmune encephalitis-related antibodies and paraneoplastic-related antibodies. The level of cerebrospinal fluid (CSF) protein was slightly elevated, and the hemagglutination assay and rapid plasma reagin test were positive in both serum and CSF samples. After 1 month of treatment with doxycycline, the patient's oral-facial-lingual dyskinesia was significantly improved, suggesting the diagnosis of neurosyphilis.