A Rare Case of Neurosyphilis Manifesting as Psychosis in an HIV-Negative Patient.

Neurosyphilis is a rare disease now, given the availability of antibiotics to treat syphilis. Patients with neurosyphilis could present with psychiatric symptoms. We present a rare case of neurosyphilis with only psychiatric symptoms. The patient was a 49-year-old male who presented with self-neglect and was not interacting with others. Treponema antibodies were positive, and rapid plasma reagin (RPR) was 1:512 with a positive venereal disease research laboratory test (VDRL) in the cerebrospinal fluid. The patient was treated with an IV penicillin regimen for neurosyphilis and improved remarkably with a return to baseline on follow-up.