Syphilis

Syphilis is an infectious disease caused by Treponema pallidum. The disease is transmitted by contact.
If untreated, syphilis can pass through four stages: primary, secondary, latent and late. The first two stages are contagious. These four stages are discussed under their separate headings.

Serologic tests
Standard tests of syphilis include the VDRL (venereal diseases reference laboratory test) and the RPR (rapid plasma reagent test).
The VDRL is usually positive by six weeks. Some cases with primary chancre will be negative because of this delay. The VDRL is almost always positive in secondary syphilis. The VDRL can continue to be reactive for years in spite of adequate treatment.
The FTA/ABS (fluorescent treponemal antibody/absorption test) becomes positive earlier than most other treponemal antibody tests. Biologic false positive reactions can occur in some patients with collagen vascular disease.

Treatment:

• Primary, secondary, and latent infections of not more than two years duration, should be treated with benzathine penicillin G 2.4 million units IM or aqueous procaine penicillin G 600,000 units IM daily for ten days. Tetracycline or erythromycin 500 mg four times daily for 15 days can also be effective.
• Late latent (more than 2 years), and tertiary syphilis are treated with benzathine penicillin G 2.4 million units weekly for three weeks or aqueous procaine penicillin G 600,000 units daily for 15 days.
• For neural or cardiovascular syphilis, the treatment is extended to 20 days.

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