Kernicterus is caused by very high levels of bilirubin. Bilirubin is a yellow pigment that is created as the body gets rid of old red blood cells. High levels of bilirubin in the body can cause the skin to look yellow ( jaundice).
If levels of bilirubin are very high or a baby is very ill, the substance will move out of the blood and collect in the brain tissue. This can lead to serious complications, including brain damage and hearing loss. The term "kernicterus" refers to the yellow staining caused by bilirubin. This is seen in parts of the brain on autopsy.
Kernicterus most often develops in the first week of life. However, but may be seen up until the third week. Some newborns with Rh hemolytic disease are at high risk for severe jaundice that can lead to this condition. Rarely, kernicterus can develop in seemingly healthy babies.
The symptoms depend on the stage of kernicterus.
Absent startle reflex
Poor feeding or sucking
Extreme sleepiness (lethargy) and low muscle tone (hypotonia)
Arched back with neck hyperextended backwards (high muscle tone/hypertonia)
Bulging fontanel (soft spot)
High-frequency hearing loss
Exams and Tests
A blood test will show a high bilirubin level (greater than 20-25 mg/dL).
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
Treatment depends on how old the baby is (in hours) and whether the baby has any risk factors (such as prematurity). It may include:
Light therapy (phototherapy)
Kernicterus is a serious condition. Many infants with late-stage nervous system complications die.
Permanent brain damage
When to Contact a Medical Professional
Get medical help right away if your baby has signs of this condition.
Treating jaundice or conditions that may lead to it can help prevent kernicterus. Infants with the first signs of jaundice have bilirubin level measured within 24 hours. If the level is high, the infant should be screened for diseases that involve the destruction of red blood cells (hemolysis).
All newborns have a follow-up appointment within 2 to 3 days after leaving the hospital. This is very important for late preterm or early term babies (born more than 2-3 weeks before their due date).
American Academy of Pediatrics. Committee on Fetus and Newborn. Hospital stay for healthy term newborns. Pediatrics. 2010; 125: 405.
American Academy of Pediatrics, Subcommittee on Hyperbilirubinemia Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics. 2004;114: 297-316.
Johnson L, Bhutani V. The clinical syndrome of bilirubin-induced neurologic dysfunction. Seminars in Perinatology. 2011; 35(3):101-113.
Kimberly G Lee, MD, MSc, IBCLC, Associate Professor of Pediatrics, Division of Neonatology, Medical University of South Carolina, Charleston, SC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.