Syphilis - Infectious Diseases in Pregnancy

SYPHILIS

Syphilis is a systemic disease caused by the motile spirocheteTreponema pallidum. The spirochete is transmitted by directcontact, invading intact mucous membranes or areas of abraded skin. A painless ulcer at the site of inoculation fol-lows, usually within 6 weeks following exposure. The ulcer is firm, with elevated edges; it lasts for several weeks. One to 3 months later, a skin rash occurs, or, in some patients, raised lesions (condyloma lata) appear on the genitalia.

T. pallidum is generally considered to cross the placentato the fetus after 16 weeks of gestation. Transmission can occur at any stage of maternal infection and has been doc-umented at as early as 6 weeks of gestation.

Spontaneous abortion, stillbirth, and neonatal death are more frequent in any untreated patient, whereas neonatal infection is more likely in primary or secondary rather than latent syphilis. Newborns with congenital syphilis may be asymptomatic or have the classic signs of the syndrome, al-though most infants do not develop evidence of disease for 10 to 14 days after delivery. Early evidence of the disease includes a maculopapular rash, “snuffles,” mucous patches on the oropharynx, hepatosplenomegaly, jaundice, lymph-adenopathy, and chorioretinitis (Fig. 15.2). Later signs in-clude Hutchinson teeth, mulberry molars, saddle nose, and saber shins.

Congenital syphilis is readily preventable with promptand appropriate maternal treatment. Therefore, all preg-nant women should be screened serologically as early as possible and again at delivery (and if exposed to an infected partner). Serologic testing is the mainstay of diagnosis. Nontreponemal screening tests (Venereal Disease Re-search Laboratory [VDRL], rapid plasma reagin [RPR]) are sometimes falsely positive; treponemal-specific tests (fluorescent treponemal antibody absorbed [FTA-ABS], T.pallidum particle agglutination [TP-PA]) are used to confirm infection and identify antibodies specific for T. pallidum. A positive treponemal-specific test result in-dicates either active disease or previous exposure; re-gardless of treatment, the test remains positive for life in most individuals.

Therapy differs by stage of disease and is generally the same as that recommended for nonpregnant adults. There are no proven alternative therapies to penicillin for treating syphilis in pregnancy. Therefore, patients with penicillin sensitivity require skin testing, followed by de-sensitization for those with a true penicillin allergy. The Jarisch-Herxheimer reaction occurs most often among patients with early syphilis and is an acute febrile reaction that typically occurs in the first 24 hours after treatment. In pregnancy, this reaction may precipitate preterm labor or cause fetal distress and may warrant close observation of mothers after treatment. Post-treatment titers (RPR or VDRL)should be followed serially for at least one year. A fourfold increase in serologic titer, or persistent or recurrent signs or symptoms, may indicate inadequate treatment or re-infection. Retreatment is indicated in either case. Response to therapy is again evaluated by following serologic titers.