Tertiary syphilis is the final, most severe stage of the disease. It can appear 10 to 30 years after the initial infection. You might experience permanent organ damage and death. Complications may include:
Neurological problems
Stroke
Infection and inflammation of membranes around the brain and spinal cord
Numbness
Deafness
Visual problems or blindness
Personality changes
Dementia
Heart valve disease
Aneurysm
Inflammation of blood vessels