What is kernicterus?

Kernicterus is a rare type of brain damage that occurs in a newborn with severe jaundice. It happens when a substance in the blood, called bilirubin, builds up to very high levels and spreads into the brain tissues. This causes permanent brain damage. Kernicterus may be prevented by treating jaundice before it gets severe.

What causes it?

Kernicterus is caused by a high level of bilirubin in a baby's blood. If left untreated, the bilirubin can then spread into the brain, where it causes long-term damage.

A low-level buildup of bilirubin is normal. This is called mild jaundice, and it gives a newborn a slightly yellowish tint to the skin and sometimes the eyes.

Normally, extra bilirubin is removed from the bloodstream by the liver and kidneys, and it leaves the body in urine and stool. During pregnancy, the mother's body removes the extra bilirubin for the baby. After birth, it takes a few days for the newborn's liver to get good at removing bilirubin from the blood. If you feed your baby every 2 to 3 hours, mild jaundice will usually go away on its own after a few days. But if there are any signs of jaundice, you and your doctor will need to watch your baby closely.

If jaundice continues to get worse and is not treated, bilirubin in the blood can build up to a high level. This is when kernicterus becomes a concern. It may be that some babies have health problems that make them more likely to have bilirubin levels that climb to high levels. For example, hemolytic disease, in which a mother's Rh blood factor is not compatible with her baby's, can make a baby produce more bilirubin than normal. Intestinal blockages can make it harder for a baby to remove bilirubin.

What are the symptoms?

Kernicterus has likely already started if a baby has certain symptoms, including:

• Extreme sleepiness. This means a baby is hard to wake or keep awake. Newborns do sleep a lot. But babies with this problem don't eat well or respond to touch. And they don't startle from sudden movements.
• A very high-pitched cry that doesn't sound normal.
• Poor muscle tone. The baby may seem "floppy" and weak. Sometimes this is followed by periods when the baby's muscles flex in a way that isn't normal. The baby may be stiff and arch their back and head.
• A fever that occurs along with any of these other symptoms.

The lifelong damage from kernicterus may cause long-term:

• Movement problems. A baby may develop slow and uncontrolled movements or random, jerky movements.
• Hearing loss or deafness. Some babies may seem to have normal hearing, but they develop a problem processing sounds. This is called auditory neuropathy or auditory dyssynchrony.
• Learning problems and other developmental disabilities.
• Problems moving the eyes, especially looking upward.

Kernicterus may cause stains on the outside (enamel) of a child's baby teeth (primary teeth).

How is it diagnosed?

Your doctor diagnoses kernicterus through a physical exam and knowledge of your child's history of symptoms. Blood tests to measure your baby's bilirubin levels are also done. Once a baby has kernicterus, brain damage has already occurred. For this reason, it is important to follow and treat jaundice before bilirubin levels get too high.

How is kernicterus treated?

Quick treatment may help prevent further brain damage. Treatment may start with light therapy and fluids given through a small tube placed in a vein (I.V., or intravenous, fluid replacement). Sometimes a baby may also have a tube placed down their throat or into the stomach for feeding with a special type of formula. A baby will also have a blood type test so that a blood transfusion can be given quickly if it is needed. A blood transfusion may be given to help remove extra bilirubin from the baby's blood.

Long-term treatment for brain damage will depend on a child's specific problems. Typical treatment includes physical therapy, speech therapy, and special education.

How can you prevent it?

You may be able to help prevent kernicterus by being aware of the symptoms of jaundice and making sure your baby gets testing and treatment when needed.

• After birth, your baby will be checked for jaundice before leaving the hospital. Your doctor or nurse may do this with a transcutaneous bilirubin test. A small device will be gently placed against your baby's skin to check the bilirubin level. A blood test can also check your baby's bilirubin level. A baby with a bilirubin level that requires treatment will have light therapy (phototherapy). This is usually given in the hospital. In very mild cases, you may treat your baby at home using lights the doctor gives you. Do not be alarmed if your baby has to have phototherapy. It does not mean that your baby is in danger of having brain damage. Doctors use this therapy to help prevent bilirubin from getting to a dangerous level.
• Feed your baby at least every 2 to 3 hours during the first week or two. This helps keep bilirubin moving out of the body through urine and stool.
• Set up a well-baby check-up before you leave the hospital. Jaundice is usually at its worst around day 5, so have the visit within the first 5 days after your child's birth. The doctor will check your baby for jaundice that is of any concern.
• Call your doctor if you think that your baby's skin on the tummy, arms, or legs is getting yellow or that yellowing on the face is getting worse. Also look for yellowing in the whites of your baby's eyes. Get medical help right away if your baby is jaundiced and is hard to wake, acts very fussy, or is not feeding well.