Cytomegalovirus (CMV) is the most common intrauterine infection and leading cause of congenital infection in Australia. CMV infection can either be a primary or less commonly, a non-primary infection. Non-primary antenatal diagnosis is complex and whilst the risk of transmission is low, symptomatic clinical manifestations can occur. Similarly, primary CMV infection does not always co-relate with CMV stigmata in a baby.
A retrospective case review of two cases of CMV infection is presented.
Case 1: After an abnormal 28-week ultrasound at a regional hospital showing unilateral ventriculomegaly and a head circumference on less than the first centile, the patient was referred to a tertiary maternal fetal medicine (MFM) unit. A repeat ultrasound showed the above and intracranial changes consistent with hypoxic brain injury, confirmed with a fetal MRI. CMV serology added onto the antenatal bloods at seven weeks showed high IgG avidity, suggesting early trimester CMV infection. CMV serology post a TORCH screen was IgG positive and IgM negative and amniocentesis confirmed CMV PCR positive amniotic fluid. After extensive counselling, the couple elected to have the pregnancy terminated at 33 weeks gestation. The post-mortem examination confirmed CMV infection.
Case 2: Gravida 2 Para 1, IVF pregnancy, had a flu-like illness at 7-10wk with documented CMV seroconversion (IgM positive, IgG positive with low avidity). The couple were referred to a tertiary MFM unit and opted to proceed to amniocentesis despite a normal morphology scan. The amniotic fluid was CMV negative. The patient had a repeat elective Caesarean section at term. Placental histology and immuno-histochemistry were positive for CMV. The male baby weighed 3730gm had a positive urine CMV and weakly positive blood CMV. He was asymptomatic with normal hearing, normal cranial ultrasound and no evidence of macrocephaly or chorioretinitis.
The difficulties of diagnosing CMV infection are highlighted in both cases. These cases demonstrate the need to use serology, non-invasive imaging and invasive in-utero investigations. The multidisciplinary care between the regional and tertiary hospital is also key in ensuring appropriate management.