Should the Traditional Algorithm for Syphilis Screening be Abandoned? Neurosyphilis Presenting as Limbic Encephalitis: A Prozone False-Negative RPR Missed by an RPR-Only Initial Screen
Introduction Neurosyphilis is a treatable mimic of viral and autoimmune limbic encephalitis. The prozone phenomenon—antibody excess preventing the antigen–antibody lattice—can render an undiluted non-treponemal test such as the rapid plasma reagin (RPR) test falsely negative, with reactivity restored on dilution. Case...