Have you ever observed that most newborns develop a slight yellow tint to their skin and the white part of their eyes? This condition is known as physiologic jaundice.¹ and occurs when their blood has an increased level of a substance called bilirubin (hyperbilirubinemia). Studies show that more than two-thirds of newborns experience physiologic jaundice in the early days of their life. This condition usually does not require treatment and resolves on its own.¹

In rare cases, however, there is too much bilirubin in babies’ blood, which, if not promptly treated, can cause damage to their brain – a condition known as kernicterus. This condition is usually irreversible. Hence, it is really important to take early signs seriously and consult a healthcare provider. ² One of the most effective treatments to prevent kernicterus is exchange transfusion. In this article, we will explore:

• What is kernicterus
• How kernicterus occurs
• Its causes and symptoms
• What is exchange transfusion, and when is it required

What is kernicterus

Kernicterus is a rare but serious condition that mostly affects newborns, particularly males.⁸ It is a long-term complication of a condition called acute bilirubin encephalopathy, where very high levels of bilirubin start affecting the baby's brain. If this early stage is not treated in time, it can progress to chronic bilirubin encephalopathy, which is what we call kernicterus.¹

Studies have found that acute bilirubin encephalopathy occurs in approximately 1 out of 10,000 newborns.¹ Another study showed that babies who are born less than thirty-seven weeks before gestation (premature birth) are at higher risk of developing kernicterus. ^1,2,3,4

How does it occur?

Bilirubin is actually a waste product, which is normally produced as a result of the breakdown of your red blood cells (RBCs), after they complete their lifespan, normally about 120 days. In newborns, however, the lifespan of RBCs is shorter. Therefore, they break down more rapidly, leading to increased bilirubin production.

Bilirubin is normally removed from your body through urine after being processed in your liver. Your liver converts bilirubin into its conjugated form, which is water-soluble and can be safely excreted in urine.¹ Moreover, conjugated bilirubin cannot enter your brain because it cannot pass through your blood-brain barrier (which protects your brain from any toxic substances present in your blood).²

In newborns, the liver is not mature enough to handle this excess bilirubin, thus leading to its accumulation in the blood. This unconjugated bilirubin travels to their brain, causing damage.

When does kernicterus occur?

Kernicterus occurs in a variety of conditions in which there is either increased production or decreased excretion of bilirubin from the body. These are discussed below.

Conditions leading to increased production of bilirubin

• Increased number of red blood cells in the body – a condition known as polycythemia⁴
• Hemolysis (destruction of RBCs) in conditions such as erythroblastosis fetalis, hereditary spherocytosis, G6PD deficiency and blood group incompatibilities, such Rh and ABO incompatibility^1,2
• Birth injuries such as cephalohematoma¹ (collection of blood under the scalp) and subgaleal hemorrhage (bleeding under the scalp)

Conditions leading to decreased excretion of bilirubin

• In newborns, the liver is not yet mature, so it cannot conjugate the bilirubin, which is required for it to pass through the blood and be removed from the body
• In conditions such as Crigler-Najjar syndrome and Gilbert's syndrome, there is a defect in the process of the conjugation of bilirubin²

Signs and symptoms

In acute bilirubin encephalopathy, you might observe the following symptoms in your baby:^1,2

• Irritability 
• Lethargy 
• Poor feeding
• High-pitched crying
• Changes in muscle tone (muscles become either floppy or stiff)
• Arching of the back or neck

Once kernicterus develops, the damage to the brain is usually permanent. This causes:

• Involuntary muscle movements
• Cerebral palsy 
• Vision and hearing difficulties 
• Intellectual disability

Management and treatment of severe hyperbilirubinemia

Kernicterus is a preventable disease if early signs of hyperbilirubinemia are recognised and managed promptly. ² Your healthcare provider may use different approaches depending on the severity of your baby's condition. These include: 

Phototherapy (light therapy)

It is usually the first and most common treatment for hyperbilirubinemia. In this procedure, a specific type of blue light is shone on your baby. It works by converting the bilirubin into a form that can be easily removed from the body. ¹ Along with phototherapy, intravenous fluids are also given to babies who have dehydration to reduce bilirubin levels.

Intravenous immunoglobulin (IVIg)

IVIg is given in those cases of blood group incompatibility, where phototherapy is not effective. It is a protein that decreases the breakdown of RBCs, leading to hyperbilirubinemia in these conditions. 

Exchange transfusion

The American Academy of Paediatrics recommends that when phototherapy does not work or when bilirubin levels are extremely high (greater than or equal to 25 mg/dl), exchange transfusion should be done immediately.⁵

What is exchange transfusion?

Exchange transfusion is a procedure in which your baby's blood is removed carefully, in small quantities and replaced with donor's blood. ¹ It is an effective procedure to decrease bilirubin levels; however, it is associated with various complications such anemia, hypocalcemia, hyperglycemia and decreased heart rate (bradycardia).⁷

How is this procedure carried out?

First, your baby’s blood is matched with donor blood to make sure it’s compatible and safe for the procedure.

To begin the exchange process, your doctor places a small, soft tube called a catheter into a blood vessel — usually in the umbilical cord area, or sometimes in another suitable vein.⁶ This allows the medical team to safely remove and replace your baby’s blood during the procedure.

Exchange process

During the procedure, your baby’s blood is removed in small amounts, and each portion is immediately replaced with the same amount of healthy donor blood. This is done slowly and carefully to avoid any sudden changes in your baby’s blood pressure, body temperature, or oxygen levels. The process continues step by step until most of your baby’s blood has been replaced with donor blood.

Throughout the exchange, your baby’s heart rate, breathing, temperature, blood pressure, and blood sugar levels are closely monitored. This careful monitoring helps ensure your baby stays stable and allows the team to quickly address any unexpected changes or complications.

How does it help to prevent kernicterus?

Exchange transfusion helps to prevent kernicterus in the following ways:¹

Removal of bilirubin

In an exchange transfusion, bilirubin is removed quickly from your baby's body before it can reach sufficiently high levels that can damage their brain.

Removal of antibodies

In conditions like erythroblastosis fetalis, babies have high levels of antibodies in their blood, which they acquire from their mother during delivery. These antibodies cause the babies’ RBCs to break down (hemolysis), thereby leading to increased bilirubin levels in their blood, which ultimately cause brain damage. ¹ Exchange transfusion removes these antibodies from their blood, thus decreasing hemolysis and bilirubin levels.

Removal of defective RBCs

In some conditions, such as hereditary spherocytosis, RBCs have an abnormal shape. This makes them more prone to destruction, which can increase bilirubin levels in the baby's blood. Exchange transfusion removes these red blood cells from the baby's and replaces them with healthy cells, which are less likely to break down.

Through these ways, exchange transfusion reduces bilirubin levels in the baby's blood, thus preventing it from causing kernicterus.

Summary

Kernicterus is a serious and irreversible type of brain damage that occurs when too much bilirubin in your baby's blood reaches the brain. To prevent this from occurring, early detection of high bilirubin levels is very important. Signs such as yellowing of the skin, eyes, or tongue should not be ignored.

To reduce high bilirubin levels, doctors may use different approaches such as phototherapy, intravenous immunoglobulins, or exchange transfusion. Exchange transfusion is typically recommended when other treatments do not work. It involves gradually replacing the baby’s blood with healthy donor blood, helping to remove excess bilirubin and other harmful substances. With prompt medical care and the right treatment, most babies recover fully and continue to grow up healthy.

FAQs

What is kernicterus, and how is it caused?

Kernicterus is an irreversible type of brain damage that occurs when a substance called bilirubin builds up to very high levels in a newborn's blood. This high amount of bilirubin crosses the blood-brain barrier and damages the brain tissues.

How to prevent my baby from getting jaundice?

One of the best ways to prevent jaundice is adequate breastfeeding, at least eight to twelve times per day for the first several days after birth. Adequate nutrition and proper hydration should also be ensured.

How can kernicterus be prevented?

Kernicterus can be prevented by reducing bilirubin levels in newborns' blood. It can be done by phototherapy, intravenous immunoglobulins and exchange transfusion.

Is exchange transfusion given to prevent kernicterus?

Yes, it prevents kernicterus by removing excess bilirubin, abnormal red blood cells and toxic substances from the blood.

Is exchange transfusion safe for my baby?

Exchange transfusion is usually kept as a last option in the treatment plan because it can lead to various complications such as infections, decreased heart rate, low calcium, and high blood sugar levels. However, the healthcare team monitors the baby closely throughout the procedure to avoid these complications.