A neonate is born at term with multiple problems. He is small for gestational age and has cataract, hepatosplenomegaly and thrombocytopenia with purpura. Fuher studies demonstrate patent ductus aeriosus, bone lucency, pneumonia, and meningoencephalitis. The mother is a 17-year-old girl who had no prenatal care and had a mild maculopapular rash in mid-pregnancy. Which of the following is the most likely diagnosis?

The rubella virus is one of the causes of devastating prenatal infection. In adults and older children, the virus can cause asymptomatic infection or a relatively mild febrile illness (German measles) with upper respiratory symptoms, lymphadenopathy, maculopapular rash, and sometimes joint symptoms. The effects on the fetus range from apparently asymptomatic infection to multiple anomalies to death in utero. Among the more common abnormalities are intrauterine growth retardation, involvement of the senses and nervous system (meningoencephalitis, cataracts, retinopathy, hearing loss), cardiac involvement (patent ductus aeriosus, pulmonary aerial hypoplasia), hepatosplenomegaly, purpura (due to thrombocytopenia), bluish red skin lesions (secondary to dermal erythropoiesis), and pneumonia. Apparently asymptomatic babies should be monitored for subsequent development of hearing loss, mental retardation, endocrinopathies, and (rarely) progressive encephalitis. Treatment is suppoive, as no specific antiviral therapy is available for this infection. The rubella vaccine should be given to women of childbearing age who are not pregnant at the time. Cytomegalovirus infections can cause asymptomatic to devastating disease in newborns; look for periventricular calcifications and mothers with a flu-like illness. Congenital syphilis can cause devastating disease in newborns and can occur in early forms (look for the rash of secondary syphilis) or late forms (look for bone and teeth abnormalities). Congenital toxoplasmosis can produce devastating infection in newborns; look for a maternal history of cleaning cat litter boxes.