FETAL SYPHILIS - CORRELATION OF SONOGRAPHIC FINDINGS AND RABBIT INFECTIVITY TESTING OF AMNIOTIC-FLUID

Fetal syphilis is the presumed diagnosis when the sonographic findings of fetal hydrops are found in the presence of maternal syphilis. In t he absence of fetal hydrops, the diagnosis of fetal infection is diffi cult. We hypothesized that intra-amniotic infection would be accompani ed by anatomic placental and fetal abnormalities that could be detecte d by ultrasonography. Rabbit infectivity testing (RIT), intratesticula r inoculation of rabbits with amniotic fluid, can be used to confirm i ntra-amniotic infection with Treponema pallidum. Twenty-one gravidas w ith untreated early (primary, secondary, and early latent) syphilis un derwent sonography and amniocentesis for RIT at 24 weeks of gestation or later. Antenatal sonographic findings were compared to their amniot ic fluid RIT results. Hepatomegaly was significantly (P < 0.01) associ ated with amniotic fluid infection detected by RIT. Antenatal detectio n of hepatomegaly, which is probably the initial sonographic manifesta tion of hydrops fetalis, may ultimately identify the fetus affected wi th congenital syphilis.