Question
At what level of jaundice in newborns might biliverdin enter the brain?
Answer
Newborn jaundice refers to the condition where, due to abnormal bilirubin metabolism during the neonatal period, bilirubin levels in the blood rise, causing yellowing of the skin, mucous membranes, and sclerae. It is one of the common clinical issues in newborns. A severe complication of newborn jaundice is biliverdin encephalopathy. When serum bilirubin levels are severely elevated or there are high-risk factors present, unconjugated bilirubin can penetrate the blood-brain barrier and enter the brain, potentially leading to biliverdin encephalopathy. This condition usually occurs within the first week after birth, with neurological symptoms appearing as early as 1-2 days after birth. Hemolytic jaundice typically occurs between 3-5 days after birth. The presence of high-risk factors such as preterm birth, asphyxia, respiratory distress, hypoxia, severe infection, hypoproteinemia, hypoglycemia, low body temperature, acidosis, or a weight below 1.5 kg may trigger biliverdin encephalopathy even if bilirubin levels are below the critical threshold.