[Diagnostic and therapy of a severe fetal parvovirus-B19-infection with persistence of viral DNA in the mothers blood but inconspicuous serological tests. Case report]

Abstract

In the 24th week of gestation we diagnosed a severe hydrops fetalis in a 25 year old VI gravid III para, who had contact to parvovirus B19 in the 14th week of gestation. Because of the severe anaemia of the fetus and the massively increased bilirubinoides in the amniotic fluid we decided at the same day to apply the first of four intrauterine transfusions. The serological patterns of maternal blood with highly positive parvovirus-B19-IgG and negative IgM suggested that an infection had occurred. Parvoviral DNA was found in maternal and fetal blood confirming the diagnosis of an acute intrauterine parvovirus-B19 infection. No viral DNA was detected in fetal ascites. IgM in fetal blood was negative. By means of four transfusions, the pregnancy could be prolonged until the 32 + 5th week of gestation while the ascites was declining. When rupture of membranes occurred, a cesarean section had to be performed due to contractions and presentation of the feet. The newborn's blood count exhibited a thrombocytopenia with normal haemoglobin and haematocrit. Five days after delivery, a blood exchange had to be done because of a hyperbilirubinaemia. After seven weeks, the child could be dismissed from hospital in good general status, with decreasing ascites, normal liver function and normal neurological status. The blood of the newborn was tested to be positive for IgG, while IgM-antibodies and parvovirus-B19-DNA were negative. The diagnosis of a parvovirus-B19 infection of a fetus with severe hydrops and anaemia could be verified by a positive proof for DNA in maternal blood, with negative IgM and highly positive parvovirus-B19-IgG and on the other hand highly positive viral DNA in fetal blood and in the amniotic fluid. 10 weeks after contact to parvovirus B19, i. e. in the 24th week of gestation, positive IgG- and negative IgM-antibodies were found in the mother's blood, whereas fetal complications were noticed. These data demonstrate that following an acute parvovirus-B19-infection of the mother IgM-antibodies can be proofed for 6 - 8 (- 10) weeks. On the other side parvovirus-B19-DNA in the mothers blood is detectable by means of PCR for 8 - 10 weeks and in some cases even more than 15 weeks.