Causes Neurosyphilis is caused by Treponema pallidum. This is the bacteria that causes syphilis. Neurosyphilis usually occurs about 10 to 20 years after a person is first infected with syphilis. Not everyone who has syphilis develops this complication. There are four different forms of neurosyphilis: Asymptomatic (most common form) General paresis Meningovascular Tabes dorsalis