Although rare, jaundice can lead to kernicterus if too much bilirubin builds up in a newborn baby’s blood and begins to damage the brain. Most babies who develop jaundice do not experience this progression. However, when jaundice becomes severe and is not recognised or treated quickly enough, the resulting brain injury can have lifelong consequences.

If your child has received a kernicterus diagnosis, you may be reflecting on the first days of their life and trying to understand how their condition developed. You may remember that their skin became yellow, that they were difficult to wake or feed, or that you raised concerns about changes in their behaviour. You may also have questions about blood test results, phototherapy or an exchange transfusion.

In this guide, we explain how newborn jaundice can progress to kernicterus, which parts of your child’s early care can explain what happened, and when medical negligence may need investigating.

How Does Jaundice Develop Into Kernicterus?

Jaundice occurs when bilirubin builds up in a baby’s blood. Bilirubin is a yellow pigment produced when old red blood cells break down.

The liver usually processes bilirubin so that the body can remove it as waste. However, a newborn baby’s liver is still developing and is unable to remove bilirubin as efficiently as the liver of an older child or adult. This is not unusual, and neonatal jaundice is common during the first few days after birth.

The most visible sign is usually the yellowing of the baby’s skin or the whites of their eyes. It may also be noticeable in their gums or inside their mouth. In babies with black or brown skin, jaundice can be harder to identify by looking at the skin alone, and the NHS has specific guidance on how to check for this.

In most babies, the condition is usually harmless and improves without treatment.

The concern arises when bilirubin continues to build up. If the amount of unconjugated bilirubin in the baby’s blood becomes dangerously high, it can enter the brain and damage delicate brain tissue.

The early stage of this process is called acute bilirubin encephalopathy. A baby may become increasingly sleepy, struggle to feed or develop changes in their muscle tone and movements. If this brain injury becomes permanent, it is known as kernicterus, or chronic bilirubin encephalopathy.

For a broader introduction to the condition, including its causes and potential long-term effects, read our guide to what kernicterus is.

What Signs May Have Shown That Jaundice Was Becoming Serious?

Families may have an increased awareness of the importance of certain signs only after their child receives a kernicterus diagnosis. At the time, they may have been told that newborn jaundice was common or that their baby was simply tired. This advice may be appropriate if the jaundice is being monitored but further concerns should be acted upon.

Signs that the jaundice was becoming more serious include:

• Yellow colouring that became stronger or spread across the baby’s body
• Yellowing of the whites of the eyes or gums
• Poor feeding or refusing feeds
• A weak sucking action
• Difficulty waking the baby
• Unusual or increasing sleepiness
• Fewer wet or dirty nappies
• A high-pitched cry
• Stiff muscles
• Arching of the neck or back
• Changes in the baby’s eye movements
• Jerking movements or seizures
• Irregular or laboured breathing

Poor feeding, increasing sleepiness and a high-pitched cry can be signs of acute bilirubin encephalopathy, meaning excess bilirubin has started to affect the brain.

Some parents may have repeatedly raised concerns about their baby’s colour, feeding or alertness. Others may have contacted a community midwife, health visitor, GP, maternity unit or hospital before their baby’s condition became critical.

Those conversations can form an important part of a medical negligence investigation. The family’s account as to these symptoms is important evidence and can establish the progress of these symptoms.

Our guide to the key symptoms of kernicterus every parent should know provides more information about the early warning signs and how the symptoms can progress.

How Would Bilirubin Levels and Treatment Decisions Explain What Happened?

Bilirubin test results and treatment records can build a timeline of how the jaundice progressed.

Medical professionals use a device placed against the baby’s skin to measure bilirubin levels. This is called a transcutaneous bilirubin meter, sometimes known as a light meter. They will also carry out blood tests to see how much bilirubin is circulating in the baby’s blood.

One result does not tell the full story. Several results taken over a period of hours will show:

• Whether bilirubin levels were rising or falling
• Whether the baby was responding to treatment
• Whether more intensive treatment needed to be considered and progressed

Doctors need to consider several factors when weighing up the significance of the results. These include the baby's age in hours, general health and any other conditions that could make them more vulnerable. Using this information, they will then make a decision on how to treat the jaundice.

Phototherapy

Phototherapy, sometimes called light therapy, is the main treatment for severe newborn jaundice.

During phototherapy, the baby is placed under specialist blue lights. The light changes the bilirubin into a form that the baby’s body can remove more easily.

Phototherapy is usually effective when it begins in time. However, where bilirubin levels are already extremely high or continue rising, the baby may need more intensive treatment.

Exchange transfusion

An exchange transfusion may be used when bilirubin levels remain dangerously high and phototherapy is not reducing these levels quickly enough, or when the baby shows signs that bilirubin is affecting the brain.

During the procedure, small amounts of the baby’s blood are removed and replaced with donor blood. This rapidly lowers the amount of bilirubin in the baby’s blood and may also remove antibodies that are causing red blood cells to break down.

The procedure usually takes place in a neonatal intensive care unit.

If your child received an exchange transfusion, the timing of the procedure and the bilirubin results before and after it may be important. Where there is an investigation into whether negligence played a part in a child's brain injury, there may be questions on when the need for transfusion first became apparent and whether the transfer to specialist neonatal care happened sufficiently promptly.

Why Did Treatment Not Prevent Kernicterus?

The fact that a baby received phototherapy or an exchange transfusion does not necessarily answer whether the treatment began soon enough to prevent brain damage.

In some cases, treatment may have started only after bilirubin had begun to affect the brain. In others, an initial course of phototherapy may not have reduced the bilirubin level sufficiently, or levels may have risen again after treatment ended.

It is reasonable for families to want answers to questions such as:

• When were bilirubin levels first measured?
• Did the results show that bilirubin was rising?
• Were adequate tests carried out?
• Did phototherapy begin at the appropriate point?
• Were bilirubin levels checked during treatment?
• Was treatment intensified when the levels continued to rise?
• Should the baby have been transferred for specialist neonatal care?
• When was an exchange transfusion considered?
• Were signs of acute bilirubin encephalopathy recognised?
• Were concerns raised by the family ignored?

Our role as medical negligence solicitors is not to make judgments as to the standard of medical treatment. We gather the available records and instruct independent experts who can assess whether the care met a reasonable standard and whether earlier action would probably have prevented or reduced the brain injury.

What Effects Can Kernicterus Have on a Child?

If kernicterus causes permanent brain damage, a child can experience lifelong effects such as hearing or vision loss, movement and coordination difficulties, feeding problems and developmental delays. Some children also develop cerebral palsy.

The impact varies from child to child and may become clearer as they grow. You can read more in our guide to the long-term effects of kernicterus.

When Could Medical Negligence Have Contributed?

A kernicterus diagnosis does not automatically prove medical negligence occurred. An investigation must consider what happened at each stage and whether earlier assessment or treatment would probably have changed the outcome. Sometimes there is one clear failure. In other cases, a series of missed opportunities may have allowed the baby’s condition to deteriorate.

One case handled by JMW showed how several missed opportunities contributed to a child’s injury. Although blood tests during pregnancy had identified that his mother had a rare blood type that increased the risk of severe jaundice, the hospital laboratory failed to pass this information to the midwifery team.

After he was born, his mother raised concerns several times about his visible jaundice and later reported worrying symptoms including poor feeding, unusual movements and signs of dehydration. Despite multiple contacts with healthcare professionals, she was repeatedly reassured and appropriate testing and treatment were not arranged until it was too late.

The investigation considered the key areas of concern and the family secured £13.4million in compensation to cover their son’s lifelong care needs.

Read more kernicterus case study examples from JMW.