a very rare type of brain damage that occurs in a newborn with severe
jaundice. It happens when a substance in the blood,
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 early before it gets
What causes kernicterus?
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
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 your baby has
any signs of jaundice, you and your doctor will need to watch him or her
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 and lethargy. This means a
baby is difficult to wake up from sleep or can't be kept awake. But keep in
mind that newborn babies sleep a lot. Lethargy in a newborn is easy to confuse
with normal newborn behavior. A lethargic baby does not eat well, does not
respond to touching or does not startle from sudden movements, and never seems
to fully wake up.
A very high-pitched cry that does not sound
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 is not normal. The baby may be stiff and arch his or her back and head.
fever that occurs along with any of these other
The lifelong damage from kernicterus may cause long-term:
Movement problems. A baby may develop slow
and uncontrolled movements or random, jerky movements.
or deafness. Some babies may seem to have normal hearing, but they develop a
problem processing sounds. This is called auditory neuropathy or auditory
moving the eyes, especially looking upward.
Kernicterus may cause stains on the outside (enamel) of a
child's baby teeth (primary teeth).
How is kernicterus diagnosed?
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
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.
Can kernicterus be prevented?
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.
If your baby is still in the hospital and has
signs of jaundice, your doctor or nurse may do a transcutaneous bilirubin test. He or she will place a small device gently 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 he or she is in danger of having brain damage. Doctors use this therapy to
help prevent bilirubin from getting to a dangerous level.
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.
Talk to your doctor
about what makes your baby more likely to get kernicterus, such as:
Being born early (more than 2 weeks
before the due date).
Having jaundice in the first 24 hours after
Having problems with breast-feeding.
bruises or bleeding on the head from a difficult birth.
older brother or sister who received light therapy for jaundice.
How is it treated?
Quick treatment may help
prevent further brain damage. Treatment may start with light therapy and fluids
given through a needle into a vein (intravenous fluid replacement). Sometimes a baby may also have a tube placed down his or
her throat or into the stomach for feeding with a special type of formula. A
baby will also have a blood type test so that he or she can quickly get a
blood transfusion 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
Other Places To Get Help
Centers for Disease Control and Prevention (CDC): National Center on Birth Defects and Developmental Disabilities (NCBDDD) (U.S.)
How this information was developed to help you make better health decisions.