Kernicterus: the dangerous condition if bilirubin in newborns is very high 2026

Although jaundice is a very common condition in the newborn, especially if it has suffered some type of bruise during childbirth or if it is a premature baby, when the levels of bilirubin in the blood reach very high values ​​it can become a dangerous disorder, potentially causing a disorder known medically as kernicterus (jaundice encephalopathy or bilirubin encephalopathy).

Jaundice consists of a yellowish discoloration of the skin and other tissues (especially the white area of ​​the eyes), very common in babies, as a result of the accumulation of bilirubin. In fact, it is estimated that it affects 50 percent of babies, although in some countries these figures can reach 60-80%.

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Labilirubin is a natural waste chemical in the blood. We find it in bile and it is formed from the degradation of hemoglobin, a protein present in red blood cells that carries oxygen from the lungs to the rest of our body. This substance is processed by the liver, but the baby's liver is not able to process it quickly enough, so it ends up accumulating.

For this reason, newborn jaundice is usually more common in premature babies and even in babies who have been bruised during childbirth, since a greater amount of blood is broken down in the bruise, forming more bilirubin.

What is kernicterus? What does it consist of?

This is a neurological condition that occurs in some newborns who have severe jaundice. It is, however, a rather rare type of brain damage, as it is uncommon, also known medically under the name of oicteric bilirubin encephalopathy (BE).

A high level of bilirubin in the blood makes the skin appear yellowish, thus causing jaundice. However, when the baby is very sick or the bilirubin level is very high, this substance tends to move outside the blood, ending up accumulating in the brain tissue if it is not bound to albumin in the blood.

That is, bilirubin can cross the blood-brain barrier. When this occurs, therefore, the risk of brain damage and hearing loss (decreased hearing capacity) increases.

Symptoms of kernicterus

The symptoms that arise when the baby suffers kernicterus depend directly on the phase in which the bilirubin encephalopathy is. However, in premature babies, it most commonly may not cause obvious clinical symptoms or signs. However, in full-term newborns some symptoms may appear, such as: lethargy, poor feeding (and excessive weight loss) and vomiting.

For example, in an early phase jaundice is usually extreme, sucking or feeding is poor, the newborn appears lethargic and has low muscle tone; Furthermore, there is no startle reflex.

In the middle phase, the newborn appears irritable, the cry is usually shrill, the muscle tone may be high, the feeding continues to be poor and the back may appear arched (with the neck hyperextended backwards).

Finally, in the late phase the crying becomes acute, there is muscle rigidity, convulsions may appear, the child does not eat, and in the end stupor and/or coma appear.

How is it treated?

While hyperbilirubin in the newborn is treated through phototherapy (which consists of a -safe- treatment in which the baby is exposed to a controlled amount of ultraviolet light, which is capable of breaking down excess bilirubin so that it can finally be excreted through the liver), there is no medical treatment once kernicterus (or, ultimately, icteric encephalopathy) develops.

Therefore, this must be prevented by treating the high level of bilirubin in the blood, to avoid reaching encephalopathy.

Thus, the treatment of jaundice in the newborn depends on the age of the baby and whether or not it presents any risk factors, such as prematurity, for example. And in addition to light therapy (phototherapy), it may also be possible to extract blood from the child and replace it with blood or fresh plasma obtained from a donor.