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Source: Knodel LC. Sexually Transmitted Diseases. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. Accessed July 16, 2012.

  • Sexually transmitted infection (STI)

  • Causative organism: Treponema pallidum, a spirochete
  • Usually acquired by sexual contact with infected mucous membranes or cutaneous lesions
    • On rare occasions can be acquired by nonsexual personal contact, accidental inoculation, or blood transfusion.

  • Organism penetrates intact mucous membrane or break in epithelium, resulting in spirochetemia.

  • Highly contagious infection that can progress to chronic, seriously disabling or fatal, systemic disease.
  • Strong evidence of association between syphilis and HIV infection.
    • Centers for Disease Control and Prevention (CDC) recommends HIV testing in all patients diagnosed with syphilis.

  • Mutually monogamous sexual relationship between uninfected partners
  • Barrier contraceptive methods

  • Unprotected sex
    • Risk of syphilis after unprotected sex with individual with infectious syphilis is ~50–60%
  • Number of sexual partners
  • Sexual preference
  • Age
    • Two-thirds of STIs occur in persons in teens and twenties.

  • Clinical presentation of syphilis varies, with progression through multiple stages possible in untreated or inadequately treat patients (Table 1).
  • Primary syphilis
    • Characterized by appearance of chancre on cutaneous or mucocutaneous tissue.
    • Chancres persist only for 1–8 weeks before spontaneously disappearing.
  • Secondary syphilis
    • Characterized by variety of mucocutaneous eruptions, resulting from widespread hematogenous and lymphatic spread of T. pallidum.
    • Signs and symptoms of secondary syphilis disappear in 4–10 weeks; however, in untreated patients, lesions may recur at any time within 4 years.
  • Latent syphilis
    • Positive serologic test but no other evidence of disease
    • Most untreated patients with latent syphilis have no further sequelae.
      • ~25–30% progress to neurosyphilis or late syphilis with clinical manifestations other than neurosyphilis.
  • Tertiary syphilis
    • Develops 10–30 years after initial infection.

Table 1. Presentation of Syphilis Infections

Signs and Symptoms

Means of Confirmation and Diagnosis

  • Serologic tests mainstay in diagnosis of syphilis; categorized as nontreponemal or ...

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