Neurosyphilis is an acquired form of dementia that develops when a person is in the latter stages of syphilis. Syphilis is one of the venereal diseases, caused by infection of the brain and spinal column by a bacterium called Treponema pallidum. It is most often acquired through sexual contact, but can also be transmitted through blood transfusions or passed on from mother to infant as part of the birth process. Prior to the development of modern antibiotics, neurosyphilis was much more common, but is seldom seen at present. It used to be called the paralysis of the insane, the result of a wicked and intemperate life.
Syphilis has an incubation period lasting from 9 days to 3 months. Then the Primary stage of the infection can begin with a sore at the point of contact — either the mouth or the sexual organs. There may be some swelling of the glands. Often the infected person does not feel ill, and the sores generally go away without treatment. After several weeks, the person will enter the secondary stage of the disease. He may develop headaches or pain in other parts of the body, loss of appetite, a feeling of malaise, and sometimes a fever. A rash may appear on some parts of the body, and there may be a loss of hair or swollen glands. This stage of the disease typically lasts between 3 weeks to 9 months. If the person does not receive treatment, he will enter a latent stage of the disease, which can last anywhere from a few months to 50 years. During this time, the person is not usually infectious to others. About 15 to 20% of those who have not yet been treated for the disease by this point will enter the tertiary stage of the disease, or neurosyphilis.
There are four different forms of neurosyphilis: asymptomatic (most common), meningovascular, tabes dorsalis, and general paresis. Symptoms include abnormal gait, blindness, dementia, hallucinations and delusions, sharp stabbing pain, depression, headache, incontinence, irritability, numbness in the lower extremities, poor concentration, seizures, stiffness in the neck, speech changes, and muscle weakness. There may also be a particular kind of visual disturbance called Argyll Robertson pupils, in which the pupils constrict when the eyes are focused on a near object, but not when exposed to bright light. There may also be abnormal reflexes, muscle atrophy, and muscle weakness.
Neurosyphilis is one form of dementia for which there are reliable diagnostic exams. Diagnosis may include various blood tests (including the Venereal Disease Research Laboratory test, Fluorescent treponemal antibody absorption, Rapid plasma reagin, and Treponema pallidum particle agglutination assay). The cerebrospinal fluid will be tested for the presence of syphilis. There may also be various nerve conduction and brain imaging studies performed. Other signs that can be diagnostic for the presence of neurosyphilis include changes in the pupil of the eye, inability to stand with the eyes closed (Romberg test), loss of sense of vibration or position, muscle weakness, gait problems, and slowly worsening dementia.
Treatment of neurosyphilis is done with penicillin or other antibiotics, with follow-up blood tests and lumbar punctures done periodically for the next three years to ensure that the infection has been eradicated. Such treatment will not cure nerve damage that has already taken place, but it will prevent or reduce new damage. Treatment of specific symptoms may also be recommended, such as anti-seizure medications. Those individuals with muscle problems may require physical or occupational therapy, and may need assistance with self-care tasks.
Persons with neurosyphilis are at risk for developing other infections. Those already infected should take special care not to expose others to the disease, by practicing safe sex. In the later stages of the disease, it may also be possible to spread the disease through skin contact, so those coming into contact with them should take precautions accordingly.