Neurosyphilis

Neurosyphilis is a severe manifestation of the bacterial infection syphilis, caused by the spirochete bacterium Treponema pallidum. This condition involves the infection of the central nervous system and can occur at any stage of syphilis. It is important to note that all symptoms of tertiary syphilis are neurological, hence are classified as neurosyphilis.

In the modern era of antibiotics, neurosyphilis is less common but is still often reported in patients with HIV due to compromised immune systems. Meningitis, an inflammation of the membranes surrounding the brain and spinal cord, is the most common neurological presentation in early syphilis.

Signs and Symptoms

The signs and symptoms of neurosyphilis are highly variable, as they depend on the stage of the syphilis disease, categorized into primary, secondary, latent, and tertiary stages.

In the secondary stage of syphilis, which usually arises within one year of initial infection, neurosyphilitic meningitis is a common manifestation. This condition typically presents symptoms similar to other forms of meningitis, with the most frequently associated symptom being cranial nerve palsy, especially of the facial nerve.

Ocular involvement can also occur, with uveitis being the most common form of ocular syphilis. Other ocular complications include episcleritis, vitritis, retinitis, papillitis, retinal detachment, and interstitial keratitis.

Meningovascular syphilis, a result of inflammation in the blood vessels supplying the central nervous system, can lead to ischemia and may present as stroke or spinal cord infarct. This typically occurs about 6-7 years after the initial infection and may affect those with early disease.

Several years to decades after the initial infection, parenchymal syphilis can present with a group of symptoms known as tabes dorsalis, a degenerative process of the posterior columns of the spinal cord. Symptoms include Argyll Robertson pupil, ataxic wide-based gait, paresthesias, bowel or bladder incontinence, loss of position and vibratory sense, loss of deep pain and temperature sensation, acute episodic gastrointestinal pain, Charcot joints, and general paresis.

Gummatous disease, which is characterized by destructive inflammation and space-occupying lesions, can also occur as a result of granulomatous destruction of visceral organs, typically involving the frontal and parietal lobes of the brain.

Diagnosis

Neurosyphilis is diagnosed via a lumbar puncture to obtain cerebrospinal fluid (CSF) for analysis. The CSF is tested for antibodies specific to Treponema pallidum antigens. The preferred test is the Venereal Disease Research Laboratory (VDRL) test, often supplemented by the fluorescent treponemal antibody absorption test (FTA-ABS).

Treatment

The primary treatment for neurosyphilis is the administration of antibiotics, typically intravenous penicillin for a period of 10 to 14 days. This is often followed by a course of oral antibiotics.

Tuskegee Study

The history of neurosyphilis research is marred by the unethical Tuskegee Syphilis Study, conducted by the United States Public Health Service from 1932 to 1972. The study observed the natural progression of untreated syphilis in approximately 400 African-American men without obtaining their informed consent. Even after the discovery of penicillin as an effective cure for syphilis, the researchers withheld treatment for the subjects. This study led to major changes in research practices, including the passing of the National Research Act in 1974, the establishment of institutional review boards, and the implementation of informed consent practices. A presidential apology was issued in 1997 in response to the study's ethical violations.

Incidence

While the incidence of syphilis has decreased with the widespread use of antibiotics, neurosyphilis still occurs, particularly among individuals with HIV. Due to the compromised immune systems of these patients, the progression from syphilis to neurosyphilis can be more rapid and severe.

Prevention

The most effective way to prevent neurosyphilis is to avoid contracting syphilis in the first place. This can be done through safe sex practices, regular STI screenings, and prompt treatment of syphilis when diagnosed. It is also crucial for individuals with syphilis to notify their sexual partners so they can also seek testing and treatment if necessary.

See Also

• Syphilis
• Sexually Transmitted Infections
• Meningitis
• Penicillin

References

• [1] Marra, C. M. (2015). Neurosyphilis. CONTINUUM: Lifelong Learning in Neurology, 21, 1714-1728.
• [2] Ghanem, K. G. (2010). Neurosyphilis: a historical perspective and review. CNS neuroscience & therapeutics, 16(5), e157-e168.
• [3] Workowski, K. A., & Bolan, G. A. (2015). Sexually transmitted diseases treatment guidelines, 2015. MMWR. Recommendations and reports: Morbidity and mortality weekly report. Recommendations and reports, 64(RR-03), 1.
• [4] Radolf, J. D., Tramont, E. C., & Salazar, J. C. (2019). Syphilis (Treponema pallidum). In Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases (8th ed., pp. 2684-2709). Elsevier.
• [5] Lukehart, S. A. (2019). Syphilis. In Jameson, J., Fauci, A. S., Kasper, D. L., Hauser, S. L., Longo, D. L., & Loscalzo, J. (Eds.), Harrison's Principles of Internal Medicine (20th ed., pp. 1154-1163). McGraw-Hill Education.

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