Differential diagnosis, investigations and treatment
Her initial serologic tests immediately after the first visit were: IgG 249 IU/ml (normal range 0-3 IU/ml) and an index of IgM 1.640 (normal range 0-0.6). All the rest antenatal tests were normal. The tests were repeated after 2 weeks and the new laboratory results were IgG 723 IU/ml and an index of IgM 1.390. During this time first trimester ultrasound and associated blood tests were performed (NT scan and PAPP-A, free b-hCG), which were found within normal range (Figure 1).
Five days later new exams were requested, with the new results being: IgG: 203 IU/ml, an IgM index of 1.38 and an IgG avidity of 49.0 (with a reference value of < 50 indicating low avidity). For confirmation of our results, after a week a new sample was sent to the Hellenic Pasteur Institute with ELISA results being IgG > 200 IU/ml (reference value of positive results >11, an index of IgM 2.61 (reference value of positive results >1.1) and IgG avidity 23% (with a reference value <40%) indicating a recent primary toxoplasmosis infection possibly within the last 3 months.
In view of these findings on the 18th week of pregnancy and 2 weeks after the last blood tests performed, an amniocentesis was requested in order to examine whether the fetus was affected. PCR-DNA test of the amniotic fluid was negative. Although there was no evidence of vertical transmission, the infection was confirmed and the patient received treatment with spiramycin 1gr three times a day (t.i.d.).
Additional serologic test of the toxoplasma gondii IgG and IgM values was performed on the 20th week of gestation found to be: IgG 149 IU/ml (with reference value of positive result >3) and IgM index 0.4 (reference value of negative result <0.5)
Second trimester ultrasound was performed on the 31st week of pregnancy were no pathologic anatomical signs found.