[Value and limits of complementary investigations in cases of toxoplasmosis seroconversion during pregnancy. A case report and review of the literature].

We report a case of acute toxoplasmosis during the first trimester of pregnancy in which antenatal diagnosis was negative. Except for non-specific signs of liver failure, assessment by repeated ultrasound scans, testing of fetal blood for toxoplasmic specific antibodies and competitive PCR to isolate the parasite, had ruled out fetal infection. In spite of early treatment with spiramycin, and although the infant was assumed to be non-contaminated, severe hydrocephalus was noted at 3 and half months of life, arising soon after therapy had been stopped. This case focuses attention on the problem of the shortcomings of the diagnostic techniques currently used, and leads us to question our practical course of action. Several questions are thus raised: how reliable are indirect signs of fetal compromise, what is the real sensitivity of the PCR test and how useful are repeated amniocentesis and inoculation of the amniotic fluid to mice.