This is the infection of the central nervous system by the bacteria Treponema pallidum. Four clinical types are often identified: asymptomatic neurosyphilis: no clinical signs or symptoms, but cerebrospinal fluid examination is positive for the infection. interstitial neurosyphilis: syphilitic leptomeningitis, vascular neurosyphilis, cerebrospinal fluid tests positive for the infection, symptomatic for meningitis, or CVA. tabes dorsalis: chronic progressive degeneration of the posterior columns of the spinal cord. general paresis: infection of the cerebral cortex: personality changes, memory loss, and loss of concentration are common.