Infections of the central nervous system caused by treponema pallidum which present with a variety of clinical syndromes. The initial phase of infection usually causes a mild or asymptomatic meningeal reaction. The meningovascular form may present acutely as brain infarction. The infection may also remain subclinical for several years. Late syndromes include general paresis; tabes dorsalis; meningeal syphilis; syphilitic optic atrophy; and spinal syphilis. General paresis is characterized by progressive dementia; dysarthria; tremor; myoclonus; seizures; and Argyll-Robertson pupils. (Adams et al., Principles of neurology, 6th ed, pp722-8)