Bilirubin is a neurotoxin in the blood that can cause brain damage--known as kernicterus--in newborns. Kernictus is a type of brain damage caused by deposits of bilirubin in the basal ganglia. There is no treatment or cure for kernicterus.
When bilirubin increases past a mild level, it leads to jaundice (yellowish discoloration of the skin) and that increases the risk of kernicterus. Jaundice usually starts in the head and progresses down the neck, chest and abdomen. Most jaundice is benign, but due to the potential toxicity of bilirubin, newborn infants must be monitored to identify those who might develop hyperbilirubinemia and in some cases, acute bilirubin encephalopathy or kernicterus. Hyperbilirubemia is an excessive level of bilirubin in the newborn's blood. Newborns are especially vulnerable to hyperbilirubinemia because in the earliest days of life, the young and still-developing liver cannot process bilirubin well.
Plotting the Risk of Hyperbilirubemia on a Nomogram
In newborns, the bilirubin level should be plotted on a bilirubin nomogram and bilirubin levels should be interpreted according to the infant's age in hours. The bilirubin nomogram is used to determine the risk of subsequent hyperbilirubinemia. If, for example, your newborn is in the "High Risk" zone on the bilirubin nomogram, there is a strong likelihood that your child will have a subsequent bilirubin level that will be high or critically elevated. Such newborns at high risk for hyperbilirubinemia should be closely monitored and assessed with repeat bilirubin levels. You can also enter the bilirubin level and the newborn's hours of life into an app called BiliTool.
The American Academy of Pediatrics issued Clinical Practice Guidelines for the Management and Treatment of Hyperbilirubinemia in 2004 and updated the clinical practice guidelines in 2009.
Risk Factors for Hyperbilirubemia
The risk factors for hyperbilirubinemia include:
- Total serum bilirubin greater than 75th percentile,
- ABO incompatibility or other hemolytic disease,
- Cephalohematoma or bruising,
- Exclusive breastfeeding,
- Discharge less than 72 hours
The only effective way at preventing kernicterus is to lower the bilirubin levels either by phototherapy or exchange transfusion. Visual inspection of jaundice is never sufficient. It is best to use a transcutaneous bilimeter or blood test to determine the newborn's risk for developing kernicterus.
If you have a question about jaundice, hyperbilirubinemia or kernicterus, we will be happy to speak with you. You can call John Fisher at 518-265-9131.