Final answer:
Infants with high levels of bilirubin in their blood can develop kernicterus, a type of brain damage. The condition arises when unconjugated bilirubin crosses the immature blood-brain barrier. Treatments like phototherapy are used to reduce bilirubin levels.
Step-by-step explanation:
When bilirubin invades the brain of an infant, a condition known as kernicterus can develop. This is a form of brain damage that occurs due to high levels of unconjugated bilirubin, which is neurotoxic, penetrating the still-developing blood-brain barrier of newborns. Bilirubin, a byproduct of erythrocyte breakdown, is typically processed by the liver and secreted in bile, ultimately being excreted in stool. However, in newborns, if the liver's ability to process bilirubin is impaired or there's excessive red blood cell breakdown, the level of bilirubin in the blood can become dangerously high, a condition called hyperbilirubinemia. This leads to jaundice and can result in significant neurological damage if not treated promptly. Newborns with hyperbilirubinemia are often treated with phototherapy because UV light helps break down bilirubin more effectively, reducing the risk of brain damage.