Neurosyphilis

Description

• A chronic, systemic, infectious disease with any involvement of the CNS at any stage of syphilitic Treponema pallidum infection (primary, secondary, tertiary, and latent)
• Transmitted sexually, via the maternal–fetal route, and via blood infusions
• Early manifestations:
  • Asymptomatic neurosyphilis: presence of CSF abnormalities in the absence of neurologic signs/symptoms; peak incidence 12 to 18 months after infection
  • Meningeal syphilis: signs and symptoms of meningitis; may be associated with gummas; onset within 12 months after initial infection
  • Meningovascular syphilis: meningitis with CNS vascular involvement, resulting in thrombosis, ischemia, and infarction; onset is 5 to 12 years after initial infection.
  • Ocular syphilis: ocular symptoms with or without meningitis; usually occurs in early infection
  • Otologic syphilis: hearing loss with/without meningitis; can occur at any time
• Late manifestations: parenchymatous syphilis
  • General paresis: also known as dementia paralytica; onset is 15 to 20 years after initial infection but may be as early as 2 years after initial infection.
  • Tabes dorsalis: also known as progressive locomotor ataxia; onset is 20 to 25 years after initial infection but may be as early as 3 years after initial infection.

Epidemiology

Incidence
See “Syphilis.” Since 2005, the Centers for Disease Control and Prevention (CDC) no longer classifies/reports neurosyphilis as a distinct stage.

Prevalence
More common in the preantibiotic era and now most often seen in patients with HIV, with predominance of early neurosyphilis compared with late neurosyphilis

Etiology and Pathophysiology

• T. pallidum, spirochete
• Meningeal and meningovascular syphilis: lymphocytic infiltration of the meninges and perivascular spaces with diffuse thickening
• General paresis: atrophy of the frontal and temporal lobes with sparing of the motor, sensory, and occipital cortex
• Tabes dorsalis: degeneration of posterior roots and column of the spinal cord

Risk Factors

• High-risk sexual behavior
• Multiple sex partners
• Men having sex with men
• Transplacental transmission
• Exposure to infected body fluids
• Inmates at adult correctional facilities
• IV drug use (rare)

General Prevention

• Routinely obtain the patient’s sexual history.
• Educate and counsel persons at risk on ways to avoid sexually transmitted infections (STIs) through changes in sexual behaviors.
• Recommend abstinence, a reduction of the number of sex partners, and the use of male condoms.

Commonly Associated Conditions

• HIV infection
• Hepatitis B
• Other STIs