Kernicterus in Newborns – Causes, Symptoms and Treatment

Newborns normally have high bilirubin levels as their organs are not fully developed. Hence, their bodies are not able to remove bilirubin properly as they should. High levels of bilirubin cause jaundice in most newborns. In rare cases, the bilirubin level in a few newborns is dangerously high, which causes a type of brain damage called kernicterus. So, medical professionals have to diagnose and treat bilirubin levels right away to bring them down in newborns to prevent brain damage or kernicterus.

What is Kernicterus?

Kernicterus is rare brain damage in newborns which is preventable. It happens in newborns with jaundice and is caused by dangerously high bilirubin build-up in the newborn’s brain. When a liver breaks down the baby’s old red blood cells into a waste product called bilirubin, the body is supposed to remove them. As newborns’ organs are not properly developed, their body is not able to remove these old red blood cells’ waste products or bilirubin. This bilirubin gets collected in the blood and causes jaundice in most newborns.

Jaundice in newborns is highly common and, sometimes, it gets treated naturally as the newborn’s body starts functioning better. However, sometimes the bilirubin levels are high, which requires medical attention. In rare cases, jaundice becomes extreme when not treated timely or, properly meaning, the bilirubin levels have reached a very high amount in the newborn’s bloodstream. Sometimes, this bilirubin gets built-up in their brain and causes brain damage or kernicterus.

Causes of Kernicterus

Some causes of kernicterus are:

• Severe or Untreated Jaundice: A newborn’s liver can’t process bilirubin properly. This results in high bilirubin in the baby’s bloodstream, causing jaundice. Severe jaundice which goes untreated or is not properly treated causes Kernicterus.
• Unconjugated Bilirubin Build-Up: Unconjugated bilirubin is converted to conjugated bilirubin in the liver. When it is not converted by the liver, it gets built up in the bloodstream and then moves to the brain tissues. This bilirubin in brain tissues causes kernicterus.
• ABO Incompatibility or Rh Disease: When the baby’s and mother’s blood type are not compatible, meaning their blood have different Rh factor or are of different types, then the mother’s antibodies destroy the baby’s red blood cells, raising the bilirubin level in the baby’s body. This is known as Rh disease or Abo incompatibility.
• Crigler-Najjar Syndrome: Babies with the inherited condition of Crigler-Najjar syndrome lack the enzyme to convert unconjugated bilirubin into conjugated bilirubin, resulting in a high level of bilirubin in the baby’s blood.

Symptoms of Kernicterus

Jaundice in newborns is common and easily detectable with yellow skin or the whites of the eyes turning yellow.  Kernicterus has more severe symptoms such as:

• Lethargy
• Crying in a shrill voice
• Low appetite
• Non-stop crying even when consoled
• Limp or floppy body
• Vomiting
• Uncontrollable body movements
• Missing reflexes
• Arching of the body (head and heels) like a bow
• Unusual eye-movements
• Less urine or stool
• Fever
• Seizures
• Muscle spasms
• Extreme fussiness
• Drowsiness
• Symptoms of jaundice- yellowing of face or other parts of the body like the whites of the eyes, arms, legs, etc.

In case of noticing any of these Kernicterus signs in the baby, immediate consultation with the doctor is a must.

Types of Bilirubin

Bilirubin is the waste product thrown out of the body when the liver processes the old blood cells. The two types of bilirubin found in the body are:

1. Unconjugated Bilirubin

Unconjugated bilirubin travels to the liver of a person from the bloodstream. As it is not water-soluble or doesn’t dissolve in water, it gets built up in the person’s body tissues.

2. Conjugated Bilirubin

Conjugated bilirubin is converted from the unconjugated bilirubin found in the liver. It is water-soluble or gets dissolved in water, so it gets easily removed from the person’s body through the intestines.

Risk Factors of Kernicterus

Babies are at risk of getting kernicterus due to the following factors:

• If they were premature

Babies born before the completion of term or 37 weeks of pregnancy are less developed, so their liver and intestine are working less effectively. Hence, bilirubin removal takes longer and can get built up in the body.

• Poor feeding 

Babies who don’t feed well have less stool and urine. Hence, the bilirubin removal is less, resulting in bilirubin build up in the body.

• Family history of infant jaundice 

Newborn jaundice can be hereditary, so if any parent or sibling of the baby had jaundice at birth or as an infant, then there are chances of the newborn getting it. This can be linked to inherited disorders such as G6PD deficiency. Such disorders cause an early breakdown of red blood cells.

• Mother with type Rh-negative or type O blood group 

Mothers with blood type Rh-negative or type O sometimes have babies with high bilirubin levels.

• Blood type difference

Blood type difference between the mother and the newborn can result in hemolytic disease. In this, the inherited antibodies from the mother in the baby attacks the red blood cells of the baby.

• Dark skin 

The yellowing of the skin due to jaundice is difficult to detect in babies with dark skin. This can result in jaundice going untreated and, thus, leading to kernicterus.

• Bruising during delivery 

During delivery, babies sometimes get a large amount of bruising. Bruising accelerates the breakdown of red blood cells and, thus, leading to kernicterus due to unconjugated bilirubin.

Complications in Babies Due to Kernicterus

Newborn or babies can have these complications due to kernicterus, which can cause long term effects in the baby:

• Athetoid Cerebral Palsy or Kernicterus Cerebral Palsy – This is a type of movement disorder caused by damage to the baby’s brain.
• Lack of muscle tone in the baby
• Muscle spasms
• Coordination issues in movements
• Deafness or hearing loss
• Eye movement problems, including trouble with looking up
• Difficulty in speaking
• Stained teeth in a baby
• Intellectual disability

Diagnosis of Kernicterus

Kernicterus mostly develops in newborns when their bilirubin level reaches an alarmingly high rate, causing severe jaundice. Sometimes, jaundice when undetected or not properly treated results in kernicterus. So, to prevent and diagnose kernicterus, newborns should be carefully watched for symptoms of jaundice for the first two days of their lives. They should be checked every 8 to 12 hours for the symptoms on the first two days and then their bilirubin level checked again before they turn five days old.

The test to check the bilirubin level is a light meter. The medical professional checks the bilirubin level of the newborn by placing the light meter on their head. The light meter then shows the bilirubin quantity in the baby’s skin or their TcB (transcutaneous bilirubin) level. The high reading of the baby’s TcB level could indicate bilirubin build up in the baby’s body. Then, the doctor will order a blood test for further evaluation of the bilirubin level of the baby. This bilirubin test is the most accurate method of measuring bilirubin levels in the baby.

Kernicterus Treatment

Once the doctor has tested the baby for kernicterus bilirubin level, they start the treatment to reduce bilirubin levels in the baby to prevent it from reaching a level where kernicterus causing brain damage. The treatments for kernicterus are:

1.  Light Therapy

Light therapy or phototherapy is a common treatment for high bilirubin levels in babies. During this treatment, the bare body of the baby is exposed to a special kind of blue light. The light accelerates the rate of breaking down the unconjugated bilirubin by the body. Then, the baby’s body can pass or remove this bilirubin through the stool or urine.

2. Blood Transfusion

Babies with a dangerously high level of bilirubin are given blood transfusion treatment. During this blood exchange transfusion, the blood of the kernicterus baby is removed slowly, little by little, and is replaced with the matching donor’s blood.

3. Frequent Feeding

Sometimes, the newborn is not getting enough milk or fluid so they are not able to discharge or get rid of waste products through their urine or stool. Hence, the more the baby feeds, the more the discharge, resulting in more bilirubin getting removed from their body.

Preventing Kernicterus

Kernicterus neonatal can be prevented by watching out for symptoms of jaundice in newborns and making sure the treatment is provided at the earliest. Preventive measures for kernicterus are:

• Regular monitoring of symptoms of jaundice in the newborn. The baby should be checked for bilirubin levels every 8 to 12 hours for the first two days of their lives
• Feeding the baby every 2 to 3 hours, so they have enough fluid in their body. This will result in the removal of bilirubin through the urine and stool.
• A thorough check-up of the newborn before leaving the hospital for jaundice and kernicterus prognosis.
• When the baby comes home, parents should keep checking if their baby’s skin is turning yellow or their the white of the eyes is turning yellow. If they notice such symptoms, they should immediately consult a doctor.

Kernicterus is rare in newborns. However, with proper diagnosis and treatment, it can be treated before it causes brain damage. Prevention is the best cure for kernicterus. Parents and medical professionals can easily prevent kernicterus with regular monitoring, proper family history sharing, and good feeding habits. Kernicterus when diagnosed early and treated right away can prevent brain damage.

Also Read:

Cerebral Palsy in Infants & Kids
Shaken Infant Syndrome
Hydrocephalus in Infants