Perinatologist Corner - C.E.U/C.M.E. Modules
Syphilis in Pregnancy
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3. Diagnosis of Syphilis
Syphilis is caused by the spirochete Treponema pallidum. The first manifestation of the disease is a painless ulcer, usually, but not exclusively, on the genitals, called a chancre. These lesions are teeming with the organism and are highly infectious. The chancre will appear approximately three weeks after exposure. Darkfield microscopic examination of scrapings of this lesion will reveal the typical “corkscrew” morphology of the infecting agent, but are often difficult to obtain outside a sexually transmitted disease-specific clinic. The clinical diagnosis of syphilis is often problematic. The chancre of primary syphilis usually causes male patients to seek care promptly, but chancres in women may be on the cervix or within the labial folds, and not easily noticed, especially since they are painless lesions. The rash, lymphadenopathy, alopecia, and condylomata lata of secondary syphilis are often evanescent, or mistaken for other less serious conditions.
Most of the syphilis that we see will be latent disease. “Early” latent syphilis implies the patient has acquired her infection within the last year, and “late” latent syphilis refers to a person who has had the diagnosis for more than a year. Latent syphilis is only diagnosable by laboratory investigation. Tertiary syphilis refers to untreated long-standing disease manifested by gumma formation in the central nervous system, iritis, or aortitis. Neurosyphilis can occur at any stage of the disease and is discussed further below.
Congenital syphilis, the disease pregnancy care providers are most anxious to prevent, results in placentitis, followed by infection of the fetus itself. Treponemal villitis results in edema, mononuclear cell infiltration, and eventual impairment of fetal oxygen transfer, which may result in fetal death. Fetal infection is similar to other “TORCH” infections with reticuloendothelial system, central nervous system, pulmonary, and skeletal involvement.