Kernicterus

What is kernicterus?

Kernicterus is a rare condition that affects your baby’s brain when they have too much bilirubin in their blood (hyperbilirubinemia). Bilirubin is a yellow waste product that your body makes. Sometimes, your liver can’t remove enough bilirubin to keep you healthy. Too much bilirubin can cause jaundice. This is when your skin, the whites of your eyes and your gums or the area underneath your tongue (mucous membranes) appear yellow.

Symptoms of kernicterus progress in stages. In addition to jaundice, symptoms usually affect newborns and include irritability, poor feeding and seizures. Complications can lead to hearing loss and permanent brain damage. If you notice changes to your newborn’s behavior or appearance, contact their healthcare provider immediately.

You may hear your healthcare provider call kernicterus “bilirubin encephalopathy.”

How common is kernicterus?

Jaundice is common in newborns. Healthcare providers will monitor newborn jaundice to decrease your baby’s risk of developing kernicterus, which is why the condition is rare.

While the condition most often affects newborns, rare cases may affect adults.

What are the signs and symptoms of kernicterus?

The first sign of kernicterus is jaundice. If your baby has jaundice, the following parts of their body will have a yellow tone:

• Skin.
• The white part of their eyes.
• Mucous membranes in their mouth.

Healthcare providers may diagnose this condition one to three weeks after birth.

In addition to jaundice, signs of kernicterus may include:

• Lack of energy (lethargy).
• Fever.
• Vomiting.
• Involuntary muscle movements.

Other signs and symptoms of kernicterus vary based on the stage of the condition.

Kernicterus stages

There are three stages of kernicterus, each with different symptoms.

• Early stage: Difficulty feeding and sucking, very sleepy, low muscle tone and no response to loud sounds (startle reflex).
• Middle stage: Irritability, a loud or high-pitched cry and tense muscles (a high muscle tone).
• Late stage: Not feeding, stiff muscles (arched back with your neck bent backward) and seizures.

Late-stage kernicterus is very serious and life-threatening. If you notice your child has jaundice in addition to any other symptoms, contact their healthcare provider immediately.

What causes kernicterus?

Very high levels of bilirubin in your blood (hyperbilirubinemia) cause kernicterus. This happens when your newborn’s liver can’t get rid of enough bilirubin.

Causes of hyperbilirubinemia may include:

• Polycythemia: Too many red blood cells in your body.
• Hemolysis: Your body destroys red blood cells. This is a natural part of a cell’s lifecycle. Sometimes, your body destroys cells too soon or more than usual.
• Injury during birth: Your baby may develop an injury during the birthing process like a collection of blood under their scalp (cephalohematoma), bleeding between their skin and skull (subgaleal hemorrhage) or bruising.
• An underlying condition that affects your child’s blood cells,like Rh hemolytic disease or a condition that affects your child’s liver, like Crigler-Najjar syndrome.

When your liver isn’t able to get rid of bilirubin through your poop, it collects in your blood before moving into your brain tissue. Bilirubin in your brain can cause severe complications.

What are the long-term effects or complications of kernicterus?

Complications of kernicterus can be life-threatening and include:

• Hearing loss.
• Cerebral palsy.
• Problems with cognitive development.
• Permanent brain damage.
• Coma.

What are the risk factors for kernicterus?

Your newborn is more at risk of developing kernicterus if they:

• Have newborn jaundice.
• Have a darker skin tone, as it can be difficult to detect yellowing skin, which is the first sign of the condition.
• Were born before 37 weeks of pregnancy.
• Aren’t eating well and, therefore, aren’t pooping to get rid of bilirubin.
• Have a biological family history of newborn jaundice.

Children who are healthy may develop jaundice. Severe jaundice can lead to kernicterus.

How is kernicterus diagnosed?

A healthcare provider will diagnose kernicterus after a physical exam and testing. Two tests include:

• A light meter test.
• A bilirubin blood test.

A light meter is a device that shines a medical-grade light on your baby’s skin. It calculates a bilirubin level based on how the light reflects off of your baby’s skin onto the device.

To confirm a diagnosis, a healthcare provider will perform a bilirubin blood test. For this test, a healthcare provider will remove a small sample of blood from your newborn’s heel. A lab will run the test to determine how much bilirubin is in your child’s body.

Imaging tests, like a head ultrasound, CT scan or MRI aren’t necessary but they may help rule out conditions with similar symptoms.

What level of bilirubin causes kernicterus?

A healthcare provider will measure the total serum bilirubin (TSB) level in your baby’s blood to diagnose kernicterus. A normal TSB level is 0.1 to 1.2 mg/dL (milligrams per deciliter). Symptoms of jaundice appear when your TSB level is 2.0 mg/dL. A test result of 25 mg/dL or more is very high and leads to a kernicterus diagnosis. If you’re unsure about test results, contact your healthcare provider.

How is kernicterus treated?

Treatment for kernicterus can include:

• Light therapy (phototherapy): Bright, ultraviolet lights shine on your newborn’s skin. These lights are medical-grade and won’t harm your child. Your newborn will rest in a bed with a light directed toward their body. Your baby will wear protective eye coverings during the treatment session.
• Exchange blood transfusions: Donor blood and/or plasma will replace your newborn’s blood. A healthcare provider will place a small tube into a vein in your child’s arm or a catheter into your child’s umbilical stump (a piece of umbilical cord left on the body that a healthcare provider cut after birth). They’ll remove and replenish your newborn’s blood supply.
• Intravenous immunoglobulins (IVIG): If your newborn has Rh disease, a healthcare provider may prescribe IVIG. This is an antibody therapy treatment. Your child will receive this treatment through an infusion into a vein in their arm.

How soon after treatment will my child feel better?

It could take up to two weeks before your child feels better. If your child has late-stage symptoms that affected their brain, complications are irreversible. Treatment and support are available to help your child adapt if complications do arise as they grow.

You can help your child feel better sooner by making sure they get enough to eat. A newborn may have feeding difficulties if they have kernicterus. A healthcare provider can give you instructions on how you can help your child get the nutrients they need if they’re not feeding well. Your child needs to meet their feeding requirements so they can poop. Passing stool helps move waste products like bilirubin out of your newborn’s body.

Can kernicterus be prevented?

There isn’t a way to prevent all causes of kernicterus. You can reduce your child’s risk of developing kernicterus by:

• Monitoring your child for jaundice after they’re born. If they have signs of yellowing on their body, contact your child’s healthcare provider.
• Attending newborn follow-up appointments. These are especially important if your child was born earlier than expected.
• Treating jaundice under a healthcare provider’s guidance. If your child has jaundice, their provider will give you instructions to treat the condition if necessary.

What is the outlook for kernicterus?

If your child receives treatment for kernicterus while the condition is in the early or middle stage, your newborn may make a full recovery. Babies who have late-stage kernicterus may have complications that can be life-threatening. Talk to your child’s healthcare provider to learn more about your child’s outlook.

In most cases, a healthcare provider will diagnose newborn jaundice and treat it before it can worsen and develop into kernicterus.

Can a baby recover from kernicterus?

If diagnosed and treated quickly, a baby can make a full recovery from kernicterus. Your child’s prognosis varies depending on the stage of the condition and what caused it.

When should my child see a healthcare provider?

Contact a healthcare provider if you notice your newborn has a yellow tone to their skin, the whites of their eyes or in their mouth within the first few weeks of their life. While jaundice is common for newborns, extremely high levels of bilirubin can be life-threatening. A healthcare provider will examine your child and test their bilirubin levels to make sure they’re healthy.

When should I take my child to the ER?

If your child has jaundice and develops other symptoms of kernicterus, like a seizure, contact 911, your local emergency services or go to an emergency room immediately. Other emergency symptoms to look out for include:

• Arching their back with their head extended back to create the letter “C” with their body.
• Crying that doesn’t stop or crying with a high-pitched scream.
• Unusually stiff muscles or weak muscles.

What questions should I ask my child’s healthcare provider?

• How often should I schedule newborn follow-up appointments?
• What stage of kernicterus does my child have?
• Are there side effects of treatment?
• How often does my newborn need light therapy?
• Did kernicterus affect my child’s brain or cause any long-term complications?

A note from Cleveland Clinic

As a newborn’s parent or caregiver, it can be worrisome to see that your child has a yellow tone to their skin and eyes. It can also be difficult to watch your child experience symptoms that you’re unable to control or fix. While jaundice is very common, kernicterus — a severe complication of jaundice caused by too much bilirubin in your child’s blood — isn’t. If something doesn’t seem right, contact your child’s healthcare provider and be their advocate. While complications are possible after kernicterus, lifelong support is available to help your child grow and learn. When diagnosed and treated early, your newborn can get back to good health.