Severe congenital cytomegalovirus infection due to maternal reinfection

Clinical History

A second trimester obstetric US in a healthy woman with a well-controlled pregnancy and normal serologic tests showed foetal ventriculomegaly. A foetal MRI was performed. Despite the imaging findings, the parents chose to continue the pregnancy. A term newborn with low birth weight, microcephaly, choriorretinitis and bilateral deafness was born.

Imaging Findings

- Second trimester foetal US (Fig. 1): Foetal ventriculomegaly.

- Foetal MRI performed at 34+5 weeks of gestation (Fig. 2): Microcephaly, mild to severe ventriculomegaly, temporo-occipital ventricular adhesions, multiple periventricular abnormalities, cystic lesions in both frontal lobes and predominantly posterior diffuse white matter disease.

- Brain US performed at 10 days of life (Fig. 3): Mild to severe ventriculomegaly, ventricular adhesions adjacent to the foramen of Monro, multiple periventricular calcifications, periventricular cyst adjacent to the right temporal horn, diffuse white matter disease and bilateral lenticulostriate vasculopathy.

- Brain MRI performed at 10 days of life (Fig. 4): Mild to severe ventriculomegaly, ventricular adhesions adjacent to the foramen of Monro, multiple periventricular calcifications, periventricular cyst adjacent to the right anterior temporal lobe, predominantly posterior diffuse white matter disease and bilateral cystic periventricular leukomalacia in both frontal lobes.

- Cranial unenhanced-CT performed at 10 days of life (Fig. 5): Mild to severe ventriculomegaly and multiple periventricular calcifications.

Discussion

Foetal ventriculomegaly is an antenatal marker for underlying anomalies. Whenever present, a search for other abnormalities such as congenital malformations, obstructive hydrocephalus, haemorrhage, leukoencephalopathy or infections is mandatory. [1]

Cytomegalovirus (CMV) is the most common congenital infection, usually acquired vertically through transplacental transmission. Maternal CMV antibodies are the main protective factor but CMV seropositive mothers can develop a secondary CMV infection either due to reactivation of virus or reinfection with a different viral strain. Infants infected as a result of a primary maternal infection are more likely to have symptoms at birth and suffer long-term sequelae than those infected as a result of maternal recurrent infection (0.2-2%). [2-5]
We present a maternal reinfection case (maternal seropositive CMV-IgG) with unusually severe foetal lesions.

Although transmission is more frequent during the third trimester, early second trimester congenital infection causes more severe lesions [2-4]. The vast majority (80-90%) of infected neonates are asymptomatic at birth. The remaining 10-20% of patients may present with neurologic deficits (microcephaly, hearing loss, choriorretinitis, seizures) and haematologic abnormalities. [2-5]

Early diagnosis is important to decide an effective treatment, to minimize neurologic sequelae and to provide appropriate parental counselling. Foetal MRI has a determinant role to demonstrate foetal abnormalities even with normal US findings. [4, 6]

In newborns, neuroimaging (US, CT, MRI) should be performed in asymptomatic neonates when serologic tests are not available, to evaluate neurological sequelae and to consider an alternative diagnosis. Furthermore, neuroimaging is important to estimate the timing of foetal infection and to predict the prognosis. [4]

Imaging findings of congenital CMV infection include foetal intracranial calcifications (particularly periventricular calcifications), ventriculomegaly, periventricular cysts (typically adjacent to the temporal horns), predominantly posterior diffuse white matter disease, ventricular adhesions, neuronal migration disorders and microcephaly. [2, 4, 5]

The diagnosis is confirmed by polymerase chain reaction (PCR) in urine or saliva in the first three weeks of life. [2, 4]

Antiviral therapy is indicated in symptomatic neonates who have not developed bilateral deafness or severe neuroimaging abnormalities. [2]

Teaching Points:

Foetal ventriculomegaly is an antenatal marker for underlying anomalies that prompts a careful search for other abnormalities.

Mothers who are CMV seropositive prior to pregnancy can also develop a secondary CMV infection either due to reactivation of virus or reinfection with a different viral strain.

Congenital CMV infection key imaging findings are ventriculomegaly and periventricular intracranial calcifications.

Imaging is important to estimate the timing of foetal infection and to predict the prognosis.

Differential Diagnosis List

Final Diagnosis

Early second trimester foetal CMV infection due to maternal reinfection.

URL:	https://www.eurorad.org/case/12807
DOI:	10.1594/EURORAD/CASE.12807
ISSN:	1563-4086