Neurosyphilis

Section of human skull damaged by late stages of neurosyphilis.

Neurosyphilis is an infection of the brain or spinal cord caused by the bacterium Treponema pallidum. It usually occurs in people who have had chronic, untreated syphilis, usually about 10 to 20 years after first infection.

Symptoms and signs

Symptoms of neurosyphilis include:

• Abnormal gait
• Blindness
• Confusion
• Dementia
• Depression
• Headache
• Incontinence
• Irritability
• Numbness in the toes, feet, or legs
• Poor concentration
• Seizures
• Neck stiffness
• Tremors

• Visual disturbances. There may be the sign of Argyll Robertson pupils, which are bilateral small pupils that constrict when the patient focuses on a near object, but do not constrict when exposed to bright light.
• Muscle weakness

Upon further diagnostic workup, the following signs may be present:

• Abnormal reflexes
• Muscle atrophy
• Muscle contractions

Diagnosis

In addition to evaluation of any symptoms and signs, various blood tests can be done:

• Venereal Disease Research Laboratory test (VDRL)
• Fluorescent treponemal antibody absorption (FTA-ABS)
• Rapid plasma reagin (RPR)
• Treponema pallidum particle agglutination assay (TPPA)

Also, it is important to test the cerebrospinal fluid for signs of syphilis.

Additional tests to look for problems with the nervous system may include:

• Cerebral angiogram
• Head CT scan
• Lumbar puncture ("spinal tap") to acquire a sample for cerebrospinal fluid analysis
• MRI scan of the brain, brainstem, or spinal cord

Treatment

Penicillin is used to treat neurosyphilis. Two examples of penicillin therapies include:

• Aqueous penicillin G 3-4 million units q4h for 10-14 days.
• One daily intramuscular injection and oral probenecid 4 times a day, both for 10 - 14 days.

Follow-up blood tests are generally performed at 3, 6, 12, 24, and 36 months to make sure the infection is gone. Lumbar punctures for CSF fluid analysis are generally performed every 6 months.