Syphilitic meningitis is a potential complication of a syphilis infection. Meningitis is an infection of the layers of tissues that cover the brain and spinal cord. It can be life threatening, but it’s treatable.

Syphilis is a sexually transmitted infection (STI) that can lead to syphilitic meningitis and other serious health issues if it’s left untreated.

Bacteria, fungi, and viruses can all cause different forms of meningitis. Syphilitic meningitis is a type of syphilitic aseptic meningitis. It’s caused by the bacterium Treponema pallidum.

Symptoms of syphilitic meningitis usually first occur in the early stages of syphilis, within several months to several years after infection.

Syphilitic meningitis may be asymptomatic at first, or there may be symptoms similar to those of other forms of meningitis. These symptoms can go unnoticed or be mistaken for another illness, such as the flu.

If left untreated, syphilitic meningitis can progress and resurface years or even decades later with more serious symptoms such as stroke, paralysis, or heart disease.

Syphilitic meningitis is a form of neurosyphilis, the phase when syphilis affects the central nervous system. Syphilitic meningitis can be life threatening, especially in its later stages, but the good news is that it’s preventable.

Early diagnosis of syphilis followed by treatment and follow-up care can reduce your risk of developing syphilitic meningitis. If it does develop, there’s treatment for it.

Syphilitic meningitis may be asymptomatic at first, or its early symptoms may go unnoticed because they can resemble other illnesses. Also, sometimes they resolve on their own. Symptoms may include:

  • fever
  • headache
  • changes in mental status, such as confusion
  • nausea or vomiting
  • changes in vision
  • pain and stiffness in the neck and shoulders
  • unexplained fatigue
  • seizures
  • sensitivity to light and noise
  • muscle aches

If untreated, syphilitic meningitis may progress and present more serious complications years later. A person might have syphilis for many years before advanced meningitis symptoms occur.

Advanced meningitis symptoms usually occur during the meningovascular stage of neurosyphilis, usually 6 to 7 years after infection. The first advanced symptom is often a stroke in a relatively young person.

Other late-stage syphilitic meningitis symptoms may include:

  • more strokes
  • heart disease
  • aneurysms
  • seizures
  • death

Syphilitic meningitis is caused by the bacterium Treponema pallidum that causes syphilis. It’s a form of neurosyphilis, which occurs when syphilis involves the central nervous system.

Syphilitic meningitis usually begins early in the primary or secondary phases of syphilis, from a few weeks to several years after syphilis infection.

Meningitis symptoms can be the first symptoms of syphilis that a person notices. It’s possible to miss the earlier symptoms of syphilis, such as painless sores and rash, which can be minor or not obvious on the body.

Syphilitic meningitis is the first symptomatic stage of neurosyphilis, which is when syphilis affects the central nervous system. An earlier asymptomatic stage of neurosyphilis may occur first.

It can take years or even decades for the most serious neurological symptoms of syphilitic meningitis to occur. Often, the first symptom of late syphilitic meningitis will be a stroke.

Even without treatment, not everyone with syphilis will develop meningitis. Syphilis is known to affect the nervous system in up to 40 percent of people with secondary syphilis and go on to cause syphilitic meningitis in 1 to 2 percent.

People may have syphilis for years without noticeable symptoms. Also, its symptoms may mimic another disease. Because of this, it’s often left untreated or misdiagnosed.

When syphilis is detected and treated promptly, complications are rare.

According to the Centers for Disease Control and Prevention (CDC), syphilis is categorized into four progressive stages:

  • Primary syphilis. This is the first stage of syphilis, marked by a small painless sore or multiple sores. The sores are located at or near the point of infection, usually the genitals, rectum, or mouth, and usually heal within 3 to 6 weeks.
  • Secondary syphilis. This is when further symptoms of syphilis begin to appear, such as fever, rash, or swollen lymph glands. These symptoms may be minor and can be overlooked.
  • Latent syphilis. In this stage of syphilis, there are no signs or symptoms.
  • Tertiary syphilis. At this stage, serious medical problems can occur involving the heart, brain, or the body’s other organs.

When the syphilis infection involves the central nervous system, it’s called neurosyphilis. There’s a common myth that syphilis only gets to the nervous system late in the disease, but this isn’t true.

In fact, neurosyphilis can occur at any stage of syphilis, but it most commonly occurs in the first two stages. Neurosyphilis can be a difficult disease to diagnose, according to research.

It can sometimes be overlooked or misdiagnosed because it’s often asymptomatic at first and because its diagnosis is complex. Its diagnosis depends on a lumbar puncture and careful analysis of clinical signs.

Also, research is limited and often contradictory. Because neurosyphilis was much more common before penicillin was introduced in the 1940s, research about it largely dates back to the first half of the twentieth century.

Current studies often rely on limited data because neurosyphilis, unlike syphilis, isn’t a reportable disease in the United States.

Also, the current increase in neurosyphilis is largely among the HIV-positive population, according to the CDC, and the connection between syphilis and HIV isn’t totally understood.

There are five types of neurosyphilis:

  • Asymptomatic neurosyphilis. This kind usually occurs within 2 years of infection and shows no symptoms.
  • Meningeal neurosyphilis. This kind occurs 3 weeks to 3 years after infection. Symptoms may include headache, stiff neck, nausea or vomiting, and vision or hearing changes.
  • Meningovascular neurosyphilis. The meningovascular type occurs 6 to 7 years after infection. Additional symptoms include stroke and vascular conditions.
  • General paresis. This occurs 3 to 30 years after infection. Additional symptoms include personality and mood changes.
  • Tabes dorsalis. This kind occurs 5 to 50 years after infection. Additional symptoms include vision loss, impaired balance, poor gait, poor reflexes.

Meningitis is just one of the many conditions that can develop when syphilis involves the body’s central nervous system. Other possible developments include:

  • blindness
  • dementia
  • paralysis
  • numbness

Syphilis is spread when one person comes into contact with the syphilis sore of another, primarily through sexual activity. About one-half of the people who have sexual contact with a partner who has the infection develop syphilis.

Examples of how syphilis can be spread include:

  • deep or French kissing, also called wet kissing
  • oral, anal, and vaginal sexual contact
  • sharing sex toys, especially porous ones, without thorough cleaning and covering with a condom
  • sharing equipment for injecting or snorting drugs

Syphilis can also be spread from a mother to her baby during pregnancy or birthing.

The CDC issued a warning in 2019 that congenital syphilis was on the rise. It noted a 22 percent increase in newborn deaths between 2017 and 2018.

About 4 out of 10 babies born to women with untreated syphilis are stillborn or die as an infant from the infection. Those who survive often have serious complications from the infection, including:

  • bone damage
  • anemia
  • enlarged liver and spleen
  • jaundice
  • blindness
  • deafness
  • meningitis

People are at greater risk for contracting syphilis if they have another STI, such as:

Having another STI makes a person more vulnerable to contracting syphilis because getting an STI is often part of an ongoing behavior of having unprotected sex. Unprotected sex is a major risk factor for syphilis.

Co-infection of syphilis and other STIs is common. Also, you should note that if you’ve had syphilis in the past, you can get it again.

After the introduction of penicillin in the 1940s, syphilis was almost eliminated in the United States by 2000. But cases have been steadily increasing since then, according to the CDC.

Between 2017 and 2018, for example, primary and secondary syphilis cases in the United States increased by 14.4 percent.

Most newly diagnosed cases of primary and secondary syphilis in the United States now occur among men who have sex with men (MSM). The CDC reports that 64 percent of the 35,000 cases of syphilis reported in 2018 were among MSM.

People who are HIV-positive and are co-infected with syphilis are at higher risk for developing neurosyphilis, according to research. The reason for this isn’t totally understood.

Some research suggests that syphilis may progress more aggressively in HIV-positive people. This may be because they often have suppressed immune systems and are taking a variety of medications.

Other researchers suggest the association between syphilis and HIV could be based on shared high-risk behaviors or participation in social networks with HIV prevalence.

A 2017 study proposes that HIV antiviral therapy may lessen a person’s immunity to the bacteria that cause syphilis. The researchers emphasize that their theory is new and needs more research for confirmation.

Co-infection of syphilis and HIV is especially common among men who have sex with men (MSM), according to the CDC. About half of MSM who have primary or secondary syphilis are also living with HIV, according to the CDC.

Neurosyphilis is still considered an uncommon disease in the United States. But its increase, especially among HIV-positive individuals, has medical researchers concerned, who say more research is needed.

What especially puzzles researchers is that neurosyphilis is occurring in HIV-positive people whose syphilis has already been treated successfully with penicillin. There’s no widely accepted explanation for why the penicillin doesn’t prevent neurosyphilis in these cases.

This condition is diagnosed with physical examinations and laboratory tests.

Examples of tests for syphilitic meningitis include:

  • the Venereal Disease Research Laboratory (VDRL) test for syphilis
  • the rapid plasma reagin (RPR) test for syphilis
  • a blood test to look for antibodies to T. pallidum
  • imaging scans of the brain
  • a lumbar puncture, also called a spinal tap, to test cerebrospinal fluid (CSF)

You’ll need to take antibiotics for several weeks if you’re diagnosed with syphilitic meningitis.

Intravenous penicillin will likely be used for 10 to 14 days. After this, your doctor may recommend weekly penicillin shots for another 3 weeks.

If you’re allergic to penicillin, alternative antibiotics are available.

Curing the infection may not end your treatment. You may also need to address the life threatening symptoms caused by infection. These include:

  • brain swelling
  • shock
  • dehydration
  • convulsions

Surgery may be needed to drain fluid from your brain or sinus cavities.

If it’s left untreated, syphilitic meningitis can quickly progress and cause serious medical complications, such as brain damage that can lead to stroke and seizures. It can even lead to death.

Don’t ignore your symptoms. Serious complications have been known to occur very soon after symptoms of syphilitic meningitis appear.

Some people recover fully from this condition. However, nerve damage can be permanent. It may be a while before your doctor is certain whether any effects are permanent. Until then, you may need help with daily activities.

Syphilis primarily spreads through sexual contact. Consistently using protection during sex can prevent infection. This includes using barriers for oral sex.

If you’re sexually active, regular STI testing is important. This aids in early syphilis diagnosis. A simple blood test can determine whether you have syphilis.

If syphilis is detected early, it can be treated with one penicillin injection. This will prevent the development of syphilitic meningitis.

If you’re pregnant, you should be screened for syphilis. The condition can increase the risk of stillbirth, and the infection can be passed from you to your child.