What Is Kernicterus?

Kernicterus is a rare kind of preventable brain damage that can happen in newborns with jaundice.

Jaundice is a yellow coloring of the skin and other tissues that affects about 60%-80% of infants in the United States. It happens when babies build up too much of a chemical called bilirubin in their blood. Normally, this condition goes away on its own. It’s only when the bilirubin level stays too high and isn’t treated that jaundice becomes kernicterus and causes brain damage.


When your baby develops jaundice, the change in skin tone usually is seen in his face first. As the bilirubin level gets higher, the symptoms can move to the rest of his body, including his chest, abdomen, arms, and legs. It’s harder to see in babies with darker skin. It can also show up in the whites of your baby’s eyes.

If your baby has any of the symptoms of jaundice, it’s important to see the doctor immediately.

  • Changes in skin color, causing a yellow or orange tint starting at his head
  • Difficulty waking up or trouble sleeping at all
  • Problems feeding, either from the breast or bottle
  • Extreme fussiness
  • Fewer than average wet or dirty diapers

Most cases of jaundice don’t require treatment, but if it goes on too long, complications can occur and it can lead to kernicterus.

Symptoms of kernicterus can vary, but may include:

  • Drowsiness or lack of energy
  • Uncontrollable or very high-pitched/shrill crying
  • Fever
  • Trouble feeding
  • Limpness or stiffness of the whole body
  • Unusual eye movements
  • Muscle spasms or reduced muscle tone

Other symptoms of kernicterus can develop as a child gets older:

  • Seizures or convulsions
  • Unusual motor development and movement
  • Muscle spasms and/or writhing
  • Hearing and other sensory problems
  • Inability to gaze upward
  • Stained tooth enamel

Diagnosis and Tests

Babies usually have their highest bilirubin level when they’re 3 to 5 days old. Newborns should be watched for jaundice every 8 to 12 hours during the first 2 days of their lives. They should then be rechecked before they’re 5 days old.


Doctors can test the bilirubin level of your newborn with a light meter before he leaves the hospital. If the result is high, the doctor can order a blood test for further evaluation. This is the most accurate way to measure bilirubin levels.

If your baby’s bilirubin level is too high, he’ll receive specific treatments depending on how many hours old he is and whether he has certain risk factors. The doctor may order more blood tests after treatment to make sure the level is going back toward a normal range.


Mild jaundice may not require treatment, but if his bilirubin level is high, or if your baby has certain risk factors (like being born prematurely), treatment may be necessary. The options may include:

Providing enough breast milk and/or formula. If your baby isn’t getting enough fluids, he may not be getting rid of enough of the yellow pigment of jaundice through his urine and stool. Newborns should have at least six wet diapers a day, and their stool should change from dark green to yellow if they’re starting to get enough nutrition. They should also seem satisfied when they’ve had enough to eat.

Phototherapy (light therapy). This involves using a special blue light on a baby’s skin in the hospital or at home to break down bilirubin. This makes it easier for a baby’s body to pass it. At one time, experts thought sunlight could help treat jaundice, but it’s no longer recommended because it can lead to sunburn. Phototherapy is considered very safe, although it may cause some temporary side effects like a loose stool and a rash.

Fluids. It is important for newborns to get enough fluids during phototherapy. Breast or bottle feeding should continue. If a baby is severely dehydrated, IV fluids may be needed.

Blood transfusion . This is done if a baby isn’t responding to other treatments and it’s necessary to quickly lower their bilirubin level. It’s only done if a baby is showing signs of brain damage from too much bilirubin.

WebMD Medical Reference Reviewed by Dan Brennan, MD on May 05, 2019



UpToDate: “Patient education: Jaundice in newborn infants (Beyond the Basics).”

National Organization for Rare Disorders (NORD): “Kernicterus.”

CDC: “Facts about Jaundice and Kernicterus.”

Merck Manual: “Kernicterus.”

Children’s Mercy Kansas City: “Introduction: Jaundice and Kernicterus Jaundice.”

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