When bilirubin finds its way into brain cells it paralyzes the energy producing mechanisms causing the cells to die.
Premature infants are particularly prone to kernicterus.
Excess bilirubin produces signs of jaundice and high levels of bilirubin in the first few days of life. The baby also becomes progressively inactive, sometimes adopting a characteristic posture with arched back and neck. Without treatment, the baby is likely to die at the end of the first week of life. Kernicterus is completely preventable if jaundice is treated adequately.