Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 6, 2016

Neurosyphilis is an infection of the spinal cord or brain. The disease is most common in people who have chronic and untreated syphilis for many years. Anywhere from 25% to 40% of people with syphilis who are not treated will develop neurosyphilis after 10 to 20 years. 


Definition & Facts

Neurosyphilis is a bacterial infection that affects the covering of the brain and/or the spinal cord. While neurosyphilis can occur at any stage of the infection of syphilis which is a sexually transmitted disease, it usually develops a decade or longer after initial infection.

Not everyone who contracts syphilis develops neurosyphilis, but up to 40% of people who do not receive treatment for the sexually transmitted disease eventually develop symptoms of this serious and life-threatening infection of the central nervous system anywhere from months to decades after infection.

Neurosyphilis can cause extensive and serious side effects ranging from personality changes to blindness and these side effects may be permanent, even after treatment. The disease can slowly progress over time, although treatment is available.

There are five forms of neurosyphilis: meningeal syphilis, meningovascular syphilis, tabes dorsalis syphilis, general paresis syphilis, and asymptomatic syphilis. Each form of the disease has different symptoms.

Symptoms & Complaints

Asymptomatic neurosyphilis, the most common form of the disease, means that the infection is present but the patient has no symptoms and does not feel ill.

Meningeal syphilis typically causes nausea, a stiff neck, headaches, and vomiting. It may also cause hearing loss and vision loss. Meningovascular syphilis has the same symptoms but it may also lead to strokes. Meningeal syphilis may occur just months to a few years after infection.

General paresis may occur anywhere from three to 30 years after the initial syphilis infection and lead to mood changes and personality changes. Hallucinations and delusions may also occur.

Patients with tabes dorsalis usually have bladder problems, poor muscle coordination, and pain in the abdomen and pain in the limbs. This form of the disease may also cause loss of reflexes, reduced sense of vibration, vision loss, poor gait, and difficulties with balance.

Tabes dorsalis may occur five to 50 years after infection. Both tabes dorsalis and general paresis are less common than the other three types of neurosyphilis today as prevention, screening, and treatment of syphilis have improved. 


Neurosyphilis is caused by Treponema pallidum, the bacteria that causes the sexually transmitted disease, syphilis. Syphilis itself is an easily treatable and preventable disease, but someone who does not receive treatment is at high risk of eventually developing neurosyphilis.

Treponema pallidum can invade the central nervous system fairly early in the course of untreated syphilis. The symptoms that result from infection of the brain are due to inflamed meninges (meningitis).

People with HIV/AIDS are at a greater risk of developing neurosyphilis. This is usually attributed to the neurological complications of HIV, which cause inflammation of the brain and spinal cord and increase the chances of Treponema pallidum infecting the central nervous system.

If an HIV-infected person contracts syphilis, it can quickly progress to the brain and spinal cord and damage the nervous system if it is not treated soon. Neurosyphilis is also more rapidly progressive in HIV patients. 

Diagnosis & Tests

There are several tests that may be done to check for neurosyphilis if someone is showing symptoms. A physical examination is usually the first step to determine if the patient has muscle atrophy or has lost muscle mass. Diagnostic exams will test the blood and test the cerebrospinal fluid. Testing a person's cerebrospinal fluid requires a lumbar puncture (also known as a spinal tap) to acquire a sample of cerebrospinal fluid.

Someone may be diagnosed with neurosyphilis after the corkscrew-shaped bacteria is visualized. The most common tests for neurosyphilis include the venereal disease research laboratory test (VDRL), fluorescent treponemal antibody absorption test (FTA-ABS), rapid plasma reagin (RPR) test, and the treponema pallidum particle agglutination assay (TPPA).

Imaging tests are used to check the brainstem, brain, and spinal cord for evidence of disease. These include magnetic resonance imaging (MRI) scans of the spinal cord or brain, head computed tomography (CT) scans, and cerebral angiograms.

Treatment & Therapy

The primary treatment for neurosyphilis is a course of penicillin, an antibiotic that is used to treat syphilis. People with neurosyphilis may be treated with antibiotics through daily intramuscular injections for up to 14 days. This is combined with an oral medication called probenecid four times a day.

Follow-up blood tests are done at 3, 6, 12, 24, and 36 months after treatment to ensure the infection is cleared. Some physicians also recommend follow-up lumbar punctures to test the cerebrospinal fluid every six months.

While treatment can cure the underlying syphilis infection, treatment will necessarily involve additional therapies to address and mitigate damage that neurosyphilis caused the body, such as blindness and physical disability.

Prognosis depends on the type of neurosyphilis that is treated and how early in the progression of the disease it is diagnosed and treated. Those who are treated years after infection have a worse prognosis than those treated early in the disease.

Someone with meningeal or asymptomatic neurosyphilis will likely return to normal health following treatment, but those with meningovascular syphilis, tabes dorsalis, or general paresis usually have long-lasting consequences.

Prevention & Prophylaxis

The best way to prevent neurosyphilis is preventing an infection of syphilis by practicing safe sex. Condoms can reduce the risk of contracting syphilis if the latex condom covers syphilis sores on a partner.

Routine blood tests for syphilis as well as regular sexually transmitted disease testing in general are also important for diagnosis and treating the infection before it progresses to neurosyphilis.