A 3-day old infant is noted to have a mildly elevated unconjugated bilirubin level and icterus. Your concern is that this child may have:

In this scenario, the infant's mildly elevated unconjugated bilirubin level and presence of icterus suggest a common occurrence in newborns known as physiologic jaundice. This condition is typically observed in infants after the first 24 hours of life due to the immature hepatic processing of bilirubin. It is generally considered normal and is expected to resolve within the first couple of weeks as the liver matures.

Physiologic jaundice results from several factors, including the increased breakdown of fetal hemoglobin, the shorter lifespan of red blood cells in newborns, and the liver's developmental stage in processing bilirubin. In contrast to pathologic jaundice, which often presents with higher bilirubin levels or occurs within the first 24 hours of birth, physiologic jaundice remains within a safe range and does not typically lead to complications if monitored properly.

While kernicterus indicates severe unconjugated hyperbilirubinemia resulting in neurological damage, it does not apply here due to the mild elevation mentioned. Additionally, glucose-6-phosphate dehydrogenase deficiency can lead to significant hemolysis and jaundice but is not considered physiologic. Pathologic jaundice, associated with underlying conditions leading to increased bilirubin production or decreased excretion