Congenital cytomegalovirus infections result from intra-uterine fetal infection by cytomegalovirus (CMV).
CMV is the most common cause of intra-uterine infection and the most common cause of congenital infective and brain damage, occurring in 0.2-2.4% of live births.
Antibodies to CMV are seen in 30-60% of pregnant women, but only 2.5% have a primary infection during pregnancy, and this can result in fetal infection in ~30% of cases.
The vast majority (90%) of infected babies are asymptomatic at birth, but some may go on to develop symptoms after 6-9 months. Some countries now keep spots of neonatal blood on special filter paper (Guthrie cards) for CMV DNA testing at a later date if needed.
Possible signs and symptoms include:
- sensorineural deafness
- intellectual disability
The degree of neurological impairment is variable, from mild learning and behavioral problems to intellectual disability and physical handicaps.
Cytomegalovirus (CMV) is a DNA virus in the herpes virus family which has the propensity to cause intrauterine infections and is part of the group referred to as TORCH infections.
- fetal intracranial calcification: mainly periventricular calcification (hyperechogenic foci), considered on the commonest of features 6
- fetal hydrocephalus
- heterogeneous appearing parenchyma
- intraventricular adhesions
- fetal intra-hepatic calcification
- fetal hepatomegaly
- evidence of intra-uterine growth restriction (IUGR)
- echogenic bowel
These findings are associated with poor outcome, allowing mothers to consider termination of the pregnancy if identified early enough.
When performed postnatally, non-contrast CT demonstrates variable features, including:
- intracranial calcifications: particularly thick and chunky in germinal matrix and periventricular regions with faint and punctate basal ganglia calcifications
- white matter low-density regions
- ventriculomegaly/cerebral atrophy/destructive encephalopathy
- neuronal migration disorders
Features seen on MRI include:
- white matter lesions: periventricular subependymal cysts representing focal areas of necrosis. They are predominantly parietal or posterior white matter involvement with spared rim in immediately periventricular and subcortical white matter.
- ventriculomegaly and subarachnoid space enlargement
- delayed myelination
- periventricular and temporal pole cysts
- migrational abnormalities: lissencephaly, pachygyria, cortical dysplasia, polymicrogyria and schizencephaly
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