mercoledì 13 dicembre 2006
Congenital Cytomegalovirus infection
Figures 1 and 2: Ultrasound images demonstrate multiple echogenic foci in a periventricular distribution. There is no hydrocephalus or evidence of callosal agenesis.
Figures 3, 4 and 5: Axial CT images show high attenuation within the subependymal region, consistent with calcifications.
Diagnosis: Congenital Cytomegalovirus infection
Differential diagnosis for congenital intracranial calcifications:
- Congenital TORCH infection
- Tuberous sclerosis
- Sturge-Weber syndrome
- Venous sinus thrombosis
Cytomegalovirus is the most common congenital viral infection in the TORCH group, and occurs as a result of transplacental transmission of the virus from an infected mother. Most infections are asymptomatic; symptomatic infections can present with a variety of manifestations, such as seizures, mental retardation, optic nerve involvement, and sensorineural hearing loss. Timing of the maternal infection during gestation may play a role in determining the severity of symptoms, with early infection leading to a more severe presentation.
Central nervous system abnormalities associated with CMV infections include calcifications, ocular deficits, parenchymal atrophy, periventricular cyst formation (occipital lobes), deafness, cerebellar hypoplasia, and ventriculomegaly. Neuronal migrational anomalies are most common in CMV infection relative to other TORCH infections.
Periventricular and subependymal calcifications are a common manifestation of CMV infection. Periventricular calcifications can also be seen in toxoplasmosis and bacterial meningitis with ventriculitis. Calcifications in CMV tend to be limited to the subependymal region, whereas in toxoplasmosis, calcifications can also seen throughout the parenchyma. Calcifications in herpes simplex and rubella are much less common. Calcified subependymal nodules may also be seen in tuberous sclerosis, however calcifications tend to occur in adolescence, as opposed to the neonatal period.
Ultrasound may also play an adjunctive role in visualizing the manifestations of CMV. Sonographic findings suggestive of CMV infection include ventriculomegaly, multiple periventricular and intraparenchymal echogenic foci (representing intracranial calcifications), gyral abnormalities, occipital periventricular cysts, and hydrocephalus.