Neurosyphilis

What is neurosyphilis?

Neurosyphilis is a rare bacterial infection of the brain or spinal cord. Neurosyphilis is different from syphilis, and it can develop when syphilis is untreated for many years. But not everyone who has syphilis develops neurosyphilis.

Neurosyphilis happens when syphilis bacteria attack the brain and nervous system. In some people, this can cause serious symptoms, which depend on the type of neurosyphilis someone has. Neurosyphilis is rare today because there are effective treatments for syphilis. 

Syphilis is a sexually transmitted infection (STI). It’s important for people who have syphilis to get treatment to prevent the development of neurosyphilis.

Types of neurosyphilis

All types of neurosyphilis can be prevented with treatment for syphilis. There are several types of neurosyphilis, which include:

• Asymptomatic neurosyphilis (ANS), the most common form, doesn’t cause symptoms. ANS happens between the first few weeks to the first few years of getting syphilis, if the syphilis isn’t treated.
• Meningeal neurosyphilis can happen within the first few months to several years after getting syphilis. People with meningeal syphilis may have headache, stiff neck, nausea, and vomiting. Sometimes, people with meningeal neurosyphilis have sensitivity to light and may have vision or hearing loss.
• Meningovascular neurosyphilis causes the same symptoms as meningeal neurosyphilis but affected people also have vertigo and leg muscle weakness. Meningovascular neurosyphilis can lead to stroke when the bacteria cause inflammation of the arterial walls. This causes blood clots to form in the arteries and block blood flow to the brain. This form of neurosyphilis can happen within the first few months to several years after syphilis infection.
• General paresis can happen 3 to 30 years after getting syphilis. General paresis is a late-stage complication of untreated syphilis. People with general paresis can have personality or mood changes, problems with thinking and judgment, memory and language problems, delusions, and seizures.
• Tabes dorsalis is another potential complication of late-stage, untreated syphilis. It causes pains in the arms and legs or abdomen, lack of muscle coordination, burning or tingling sensations (called lightning pains), and bladder control and sexual function problems. Other signs include vision loss, loss of reflexes, loss of sense of vibration, and walking and balance problems. Tabes dorsalis can happen anywhere from 5 to 50 years after a person is first infected with syphilis. 

Who is more likely to get neurosyphilis?

Neurosyphilis can affect anyone who has syphilis, especially people who don’t get treatment for months or years. People who have unprotected sex are at high risk for syphilis. 

People with HIV are also at higher risk of having neurosyphilis, possibly due to a weakened immune system.

General paresis and tabes dorsalis are now less common than the other forms of neurosyphilis because of advances in the prevention, screening, and treatment of syphilis.

How is neurosyphilis diagnosed and treated?

Diagnosing neurosyphilis 

A healthcare provider will do a physical exam and ask about the person’s medical history. They’ll also do a neurological exam to check for problems with the nervous system. If they think the person has neurosyphilis, they can use other tests to help diagnose neurosyphilis: 

• Cerebrospinal fluid (CSF) tests through a lumbar puncture (spinal tap) to detect signs of syphilis
• Blood tests to detect syphilis bacteria
• A cerebral angiogram to see how blood flows through the brain
• Head CT (computed tomography), spine CT, or MRI (magnetic resonance imaging) scans of the brain and spinal cord to look for nervous system problems and rule out other diseases

 Learn more about neurological diagnostic tests and procedures.  

Treating neurosyphilis

Neurosyphilis is a life-threatening complication of syphilis. If a person has had syphilis in the past and develops signs of nervous system problems, they should seek immediate medical attention. Diagnosis and treatment of the syphilis infection can prevent neurosyphilis and keep it from getting worse. 

Doctors use penicillin, an antibiotic, most often to treat syphilis. Some healthcare providers recommend another antibiotic called ceftriaxone for neurosyphilis treatment. A person being treated for neurosyphilis should get follow-up lumbar punctures for CSF every six months and periodic blood tests—such as at three months and six months—to make sure the infection is gone.

A person who has HIV or another medical condition may have a different follow-up schedule. Treatment outcomes are different for every person. Antibiotics may stop neurosyphilis from getting worse, but neurological damage may not be reversible.

The prognosis (outlook) for a person with neurosyphilis depends on the type they have and how early the disease is diagnosed and treated. People with asymptomatic neurosyphilis or meningeal neurosyphilis usually return to normal health. People with meningovascular neurosyphilis, general paresis, or tabes dorsalis usually don’t return to normal health, although they may get much better.

If neurosyphilis isn’t treated, it can lead to serious complications including permanent paralysis, dementia, and death. Getting treatment soon after syphilis infection can prevent the worst outcomes of neurosyphilis.

What are the latest updates on neurosyphilis?

NINDS, part of the National Institutes of Health (NIH), is the leading federal funder of research on the brain and nervous system, including disorders such as neurosyphilis. NINDS supports new and innovative research to better understand, diagnose, and treat neurosyphilis and related disorders. 

Patients with syphilis who are also infected with HIV may be at increased risk of neurosyphilis. One NINDS-funded research study is using genetic and immunological tests to find out why some people with syphilis get neurosyphilis and why some people don't. 

Brain atrophy, otherwise classified as CNS neurodegeneration (CNS-ND), is a common feature of various neurological diseases such as Alzheimer's disease, cerebral palsy, dementia, encephalitis, neurosyphilis, and neuroAIDS. In a NINDS-funded study, researchers have developed unique animal models of brain atrophy to determine the cellular and molecular basis for CNS-ND.    

New reports of syphilis and congenital syphilis are increasing at an alarming rate in the U.S. Syphilis is caused by the bacterium Treponema pallidum. Benzathine penicillin G (BPG) is one of just a few antibiotics known to effectively treat syphilis. There is currently a shortage of BPG, and some people are allergic to penicillin antibiotics. In response, the National Institute of Allergy and Infectious Diseases (NIAID) is researching alternative therapies to BPG for the treatment of adult syphilis, neurosyphilis, and syphilis in pregnancy and infancy. This work is part of NIAID’s comprehensive portfolio of syphilis diagnosis, prevention, and treatment research.  

For more information on research about neurosyphilis, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.

For research articles and summaries on neurosyphilis, search PubMed, which contains citations from medical journals and other sites.

How can I or my loved one help improve care for people with neurosyphilis?

Consider participating in a clinical trial so clinicians and scientists can learn more about neurosyphilis and related disorders. Clinical research with human study participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities. This helps make sure that study results apply to as many people as possible and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research, visit the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with neurosyphilis at ClinicalTrials.gov, a searchable database of current and past clinical studies and research results.

Learn about related topics

• Neurological Complications of HIV