 Neurosyphilis refers to an infection involving the central nervous system . It may occur early , being either asymptomatic or in the form of syphilitic meningitis , or late as meningovascular syphilis , general paresis , or tabes dorsalis , which is associated with poor balance and lightning pains in the lower extremities . Late neurosyphilis typically occurs 4 to 25 years after the initial infection . Meningovascular syphilis typically presents with apathy and seizure , and general paresis with dementia and tabes dorsalis . Also , there may be Argyll Robertson pupils , which are bilateral small pupils that constrict when the person focuses on near objects but do not constrict when exposed to bright light . 
