[Symptomatic cytomegalovirus infection through breastfeeding in a 45 days old boy]. / Infección sintomática por citomegalovirus a través de la lactancia materna en un niño de 45 días.

Postnatal infection or acquired cytomegalovirus in the newborn is transmitted by maternal cervical secretions at birth, breastfeeding, blood transfusion or biological fluids. Breast milk is the main source of infection. Clinical manifestations depend on the gestational age and birth weight, premature and low birth weight newborn being more vulnerable. Postnatal infection usually resolves spontaneously without antiviral treatment; the risk of long-term sequelae is lower than in congenital infection. We describe the case of a 45 days old male patient, term newborn appropriate for gestational age, with a very rare condition characterized by severe thrombocytopenia secondary to postnatal cytomegalovirus infection. We detail its symptoms, clinical evolution, diagnosis and treatment employed.