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Kernicterus is a severe form of brain damage that mainly occurs in newborns. It develops when severe jaundice is left untreated.

Newborns commonly get jaundice because their bodies are less able to remove bilirubin, a by-product from the liver breaking down old red blood cells. Of all newborns, roughly 60% will get jaundice. If the jaundice is severe and isn’t promptly treated, toxic levels of bilirubin in the brain can lead to kernicterus.

In developed nations such as the U.S., kernicterus is relatively rare because healthcare professionals usually treat jaundice early. But without early detection and proper treatment, Kernicterus can lead to severe illness, long-term harm, and even death. If your child developed kernicterus as the result of medical negligence, Birth Injury Center may be able to help.

What Are the Symptoms of Kernicterus?

Kernicterus starts with jaundice. Typically, jaundice symptoms begin on the baby’s face, where you’ll notice a recognizable yellowish tint to their skin. As bilirubin levels increase, the yellowing will move to their chest, arms, legs, belly, and even the whites of their eyes. It’s especially important to pay close attention to symptoms in babies with darker skin, as it’s easier to miss the yellow tint.

Signs and symptoms of jaundice include:

  • Yellow or orangish skin color all over the baby’s body, starting at the head
  • Problems breast or bottle-feeding
  • Extreme fussiness
  • Trouble sleeping or waking up
  • Few wet and dirty diapers (Per La Leche League, a breastfed newborn should produce about three to four stools daily and four to six thoroughly wet diapers by day four.)

If you notice signs of jaundice in your infant, contact your pediatrician to determine the best course of action.

Most cases of infant jaundice are mild and will resolve within a week or so. However, in 8% – 9% of cases, the infant develops severe jaundice. Severe jaundice symptoms include trouble sleeping and unusual eye movements, and the infant needs immediate medical attention to avoid developing Kernicterus.

Because jaundice is so common and because severe jaundice can lead to permanent brain damage, healthcare professionals should examine babies regularly after birth.
Babies’ bilirubin levels normally peak between three and seven days old, so babies are typically examined for jaundice every 8 to 12 hours in the first two days. They should also be assessed again within two or three days of discharge, depending on other factors such as age during discharge.

When healthcare professionals neglect to test for and treat severe jaundice, the infant can develop kernicterus. An infant’s bilirubin can reach toxic levels, damaging brain cells and causing new symptoms like respiratory distress and muscle spasms.

Signs and symptoms of kernicterus in infancy include:

  • High-pitched, inconsolable crying
  • Arched backStiff, limp, or floppy body
  • Lack of energy
  • Strange eye movements
  • Breathing problems
  • Reduced muscle tone and muscle spasms
  • Fever

If you note these symptoms in your baby, seek emergency medical attention.

Because kernicterus can permanently damage brain cells, children might develop new symptoms of kernicterus even years after treatment. These symptoms can be permanent and create life-long disabilities.

Long-term symptoms of kernicterus include:

  • Convulsions or seizures
  • Writhing and muscle spasms
  • Unusual motor development and movement
  • Stains on teeth enamel
  • Sensory challenges, primarily hearing
  • Inability to gaze upwards
  • Difficulty speaking

Kernicterus can have these long-term effects because it affects several key parts of the brain, especially those associated with movement. The regions affected in most cases include:

  • Basal ganglia: This is primarily responsible for motor control.
  • Hippocampus: Plays a key role in memory and learning.
  • Geniculate bodies: A part of the thalamus that helps process vision.
  • Cranial nerve nuclei: These include the cochlear (hearing), vestibular (movement), and oculomotor (vision).
  • Cerebellum: Responsible for postural adjustments to maintain balance.

Causes of Kernicterus in Newborns

Ultimately, kernicterus occurs when severe jaundice goes untreated and causes toxic levels of bilirubin that create this long-term brain damage.
Essentially it all boils down to the levels of bilirubin. As such, it’s important to understand that there are two types of bilirubin in the body:

Unconjugated bilirubin:

This type of bilirubin is not water-soluble and can travel from the bloodstream to other parts of the body where it can build up.

Conjugated bilirubin:

This is water-soluble bilirubin that occurs when the liver converts unconjugated bilirubin. As such, it can be removed from the body through the intestines.

Because unconjugated bilirubin builds up, it’s usually responsible for severe jaundice and kernicterus.

Risk Factors

While any baby can be at risk of this build-up, several risk factors and conditions make developing kernicterus more likely.

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Preterm Birth

Babies born prematurely (before 37 weeks gestation) have an increased risk of jaundice. Most babies this age do not have a fully developed liver yet and are not able to get rid of high levels of bilirubin

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Feeding Difficulties

Feeding problems, especially during the first few days, can put babies at a higher risk of jaundice.

Siblings with jaundice
Sibling With Jaundice

If any of your other children had jaundice when they were infants, your new infant is more likely to get jaundice.

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Babies With Darker Skin Color

One of the earliest signs of jaundice is the skin becoming yellowish. With darker skin babies, this may not be easy to notice. The best places to check include the inner lips and gums.

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During birth, the baby can be bruised. Bruises are made up of blood, so the process of healing the bruises gives the baby’s body extra bilirubin to deal with. This can lead to jaundice.

Rh Disease In some cases, the mother and baby may have incompatible blood types. Some people have a certain protein known as Rh factor attached to their red blood cells, while others do not. An Rh-negative mother does not have this protein. If her baby is Rh-positive, then the baby’s red blood cells do have the protein. When this happens, it’s known as Rh incompatibility. If red blood cells from the baby enter the mother’s bloodstream, then the mother’s immune system will perceive the foreign Rh factor as a threat, and will develop antibodies against it. When these antibodies pass through the placenta, they’ll begin attacking the baby’s red blood cells.

This doesn’t usually happen during a first pregnancy, because the baby’s blood and the mother’s blood don’t mix through the placenta. However, it’s common for the mother to be exposed to the baby’s blood during delivery. If she gets pregnant with another Rh-positive baby, then the new baby will be at high risk of being affected by Rh disease, because the mother’s body is now producing antibodies against Rh factor.

As a result, the baby’s bilirubin levels rise and can build up in their bloodstream after birth. However, this condition is rare as long as the mother has gotten adequate prenatal care, since Rh incompatibility can now be treated during pregnancy.

Crigler-Najjar syndrome is a hereditary condition that leaves babies without an enzyme necessary for converting unconjugated bilirubin to conjugated bilirubin, leading to a build-up.

Kernicterus Treatment Options

Kernicterus is a preventable condition, and ideally, no child should develop it. Once kernicterus is identified, the treatment works to prevent further brain damage by quickly reducing the levels of bilirubin. Such kernicterus treatment options include:

Feeding the Baby Adequately

The first course of treatment for severe jaundice is to ensure the infant gets adequate nutrition, either with breast milk or formula. Once the baby begins feeding well, they’ll have at least six wet diapers daily. You’ll also notice that the color of their stool will change from dark green to yellow.

Phototherapy (Light Therapy)

Phototherapy breaks down bilirubin by exposing the baby’s skin to a special blue light, making it easier to pass. During phototherapy, the baby is placed under a light or on top of a blanket that emits blue light. If the baby’s jaundice has developed into kernicterus, doctors might speed up the treatment by using several lights. Treatment will continue until bilirubin reaches safe levels.

Often, phototherapy takes a day or two. At the start of this period, doctors usually test for bilirubin levels every four to six hours and then every six to twelve hours as the baby’s levels drop.

Plasma Transfusion

If the baby does not respond to light therapy, the doctor may suggest a plasma transfusion. This can only be done if the baby has high bilirubin levels and shows signs of brain damage. This process involves gradually replacing the baby’s blood with that from a suitable donor. After two hours of treatment, another bilirubin test will be performed. If necessary, doctors may do another transfusion.

Long Term Care for Infants with Kernicterus

Depending on the extent of the brain damage, a child with kernicterus can have life-long impairments. People with kernicterus might have movement problems, hearing loss, auditory neuropathy, developmental disabilities, and learning problems.

As such, long-term care of kernicterus varies from patient to patient. However, it’s always good to take a proactive approach to identify symptoms and limit their magnitude.

Uncontrolled body movements
Uncontrolled Body Movements

Uncontrolled body movements are a common long-term effect of kernicterus. To help address these movements, enhance their coordination by ensuring your child is physically active. Your doctor may recommend exercises and stretches for infants. As they grow, you can also add walking, balancing exercises, and swimming.

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Auditory Neuropathy

There’s no medical treatment to cure auditory neuropathy, which can cause hearing loss and deafness. Fortunately, there are interventions such as hearing aids, remote microphone systems, or cochlear implants to improve your child’s hearing.

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Speaking Difficulty

Children with kernicterus can have difficulty speaking. Fortunately, there are speech therapy exercises that you can do with your child to help them improve.

Written by:
Birth Injury Center Team

The Birth Injury Center aims to create informational web content and guides to help women and their families seeking support and guidance for birth injuries caused by medical negligence. All of the content published across The Birth Injury Center website has been thoroughly investigated and approved by medical expert Natalie Speer, RNC-OB, Attorney Ryan Mahoney.