CMV is the largest of the herpes viriolae group and incidence of congenital CMV infection in the western countries ranges from 0.2 to 2.4% of all live births. The risk for fetal infection is greatest with maternal primary CMV infection (30%) and much less likely with recurrent infection (<1%). Perinatal transmission has an incidence of 10-60% and can occur during the 1st 6 months of life with mode of transmission being the genital tract secretions at delivery and through breast milk.

Symptomatic congenital CMV infection was originally termed cytomegalic inclusion disease. (hepatosplenomegaly, jaundice, petechiae, purpura and microcephaly). Other features seen are intrauterine growth retardation, prematurity and intracranial calcifications. Other neurologic problems include chorioretinitis, sensorineural hearing loss. Only 5% of all congenitally infected infants have severe cytomegalic inclusion disease, 5% have mild involvement and 90% have subclinical but chronic CMV infection. Perinatally acquired CMV can lead to pneumonia and sepsis like syndrome, however most are asymptomatic.

Symptomatic congenital CMV has presentations:

	Early manifestation: Presents with involvement of multiple organ systems with a high risk of mortality. Findings include petechiae or purpura, hepatosplenomegaly, jaundice and “blue berry muffin spots” consistent with extra medullary hematopoiesis. Laboratory abnormalities include elevated hepatic transaminases, hyperbilirubinemia, anemia and thrombocytopenia.
	A second early presentation includes those infants who are symptomatic but without life threatening complications. These babies may have IUGR or microcephaly with or without intracranial calcifications. These calcifications are classically seen in the periventricular area as was seen in our case. Patients may have chorioretinitis, sensorineural deafness and developmental abnormalities.

Those with asymptomatic infection may have hearing loss, mental retardation, motor spasticity and microcephaly with abnormal enamel production later in life.

Diagnosis

Diagnosis is by viral isolation or PCR which should be performed at or shortly after birth in urine, saliva, blood or respiratory secretions. If found within first 2 weeks of life, it denotes congenital infection. If found after 4 weeks of life, it may denote perinatal infection. CMV antigen can be detected in blood. Positive results confirm CMV infection and viremia; however, negative results do not rule out CMV infection.

Maternal serum antibodies (CMV specific IgG) show a decline within a month and uninfected children have no detectable titer by 4 to 9 months. Infected infants continue to produce IgG throughout the same time period. Our patient had a high CMV IgG even at the age of 10 months suggestive of CMV infection in the child. IgM tests lack specificity and sensitivity for diagnosis of congenital CMV.

Treatment

Treatment by ganciclovir (6 mg/kg/dose IV 12 hourly) for first 6 weeks of life has demonstrated improved hearing and prevention of hearing deterioration though drug-related toxicity is common. Treatment with ganciclovir is still under evaluation.