A newborn infant becomes markedly jaundiced on the second day of life, and a faint petechial eruption, first noted at birth, is now a generalized purpuric rash. Hematologic studies for hemolytic diseases are negative. Acute management should include which of the following?

Although hypothyroid neonates may develop hyperbilirubinemia, the patient described most likely has a congenital or acquired infection requiring immediate diagnosis and, if possible, treatment. Among the important causes of neonatal sepsis are prenatal infections, including congenital syphilis, toxoplasmosis, cytomegalovirus infection, and rubella. Useful diagnostic studies, in addition to cultures for bacteria, include specific serologic tests for pathogens, viral cultures, lumbar puncture, and x-rays of the chest and long bones. Longitudinal striations in the metaphysis are characteristic of congenital rubella, whereas osteochondritis or periostitis usually indicates congenital syphilis. Congenital syphilis, cytomegalovirus, and rubella can be highly contagious. Urine can contain rubella virus for more than 6 months and is, therefore, a special hazard to nonimmune pregnant women.