In utero herpes simplex encephalitis

Transplacental intrauterine infection with herpes simplex virus is an extremely rare complication of primary herpes simplex in pregnancy. Overwhelming fetal sepsis might result in multiorgan failure, including fetal brain death.

A 34-year-old multigravida presented with a healing ulcerative genital rash at 16 weeks' gestation. She subsequently reported at 28 weeks' gestation that there had been no fetal movements for 2 weeks. A cardiotocograph showed absent short- and long-term variability. At delivery, an infant was born with disseminated herpes simplex infection in poor condition. Active treatment was subsequently withdrawn, and postmortem examination confirmed disseminated herpes simplex type 2 infection.

Transplacental herpes simplex is a rare and potentially lethal form of congenital herpes. Overwhelming in utero sepsis should be considered in the differential diagnosis of fetal brain death.