Kernicterus: Symptoms, Causes, Classification, Treatment, Prevention

What is Kernicterus?

Kernicterus is an extremely rare bilirubin-induced brain damage, which occurs in newborns suffering from severe jaundice. Kernicterus occurs when there is accumulation or rise of bilirubin levels in the blood. This then spreads to the tissues of the brain. Depending on the spread of the bilirubin to the brain, the patient can have mild to permanent brain damage and in some cases even death. Prevention of Kernicterus can be achieved by treating jaundice as soon as it gets detected and before it gets severe.

What is Kernicterus

Signs & Symptoms of Kernicterus

Certain symptoms indicate that the baby has Kernicterus:

  • The baby suffering from Kernicterus has extreme sleepiness and lethargy. It is difficult to wake the baby up from his/her sleep or the baby can’t be kept awake. However, it should also be born in mind that newborn babies tend to sleep a lot. Same goes for lethargy, which can be seen in a newborn baby and also be confused with the normal behavior of a newborn baby.
  • If the baby is lethargic then the baby does not feed well, does not get startled from sudden movements or noises, does not respond to touch and never seems to completely wake up.
  • The Kernicterus baby also has very high-pitched cry, which does not sound normal.
  • The baby suffering from Kernicterus has symptoms of poor muscle tone and the body of the baby seems weak and “floppy.” In some cases, this is followed by episodes where the muscles of the baby flex in a way which is not normal. There is stiffness felt in the baby and the baby will arch his/her head and back.
  • Fever can also be present along with these symptoms.

The potential permanent damage resulting from kernicterus can also cause long-term:

  • Movement problems where the baby can develop random and jerky movements; or uncontrolled and slow movements.
  • Hearing loss or deafness can also occur. Sometimes the baby may seem to have normal hearing; however, they have difficulty in processing the sounds. This condition is known as auditory dyssynchrony or auditory neuropathy.
  • The baby suffering from Kernicterus can also have developmental disabilities and learning problems.
  • There will be problems with the eye movements, especially looking upwards.
  • The baby’s primary teeth may have stains on the enamel due to kernicterus.

Classification of Kernicterus

Acute Bilirubin Encephalopathy (ABE): This is an acute condition where there is an increase of bilirubin in the central nervous system. The baby has wide range of symptoms such as decreased feeding, lethargy, high-pitched cry, hypertonia or hypotonia, spasmodic torticollis, opisthotonus, sunset eye sign, seizures, fever, and even death. The bilirubin needs to be reduced rapidly, if not then Acute Bilirubin Encephalopathy progresses to Chronic Bilirubin Encephalopathy.

Chronic Bilirubin Encephalopathy (CBE): This is a chronic state where the baby has severe neurological lesions induced by bilirubin. Decrease in the bilirubin in this stage will not reverse the consequences. The symptoms in this stage include movement disorders such as dystonia or athetoid cerebral palsy; auditory dysfunction, such as auditory neuropathy, oculomotor impairments (strabismus, nystagmus, impaired downward/upward gaze, cortical visual impairment), dysplasia of the deciduous teeth/dental enamel hypoplasia, impaired digestive function and gastroesophageal reflux. Lesions in the basal ganglia, oculomotor nuclei of the brain stem and auditory nuclei of the brain stem result in the above mentioned impairments.

Subtle Bilirubin Encephalopathy (SBE): This is a chronic state of neurological dysfunction which is induced by mild increase in the bilirubin levels. This may result in movement, learning and neurological disorders, auditory dysfunction and isolated hearing loss.

Causes of Kernicterus

The cause of Kernicterus is increased levels of bilirubin in the blood of the newborn baby. If this is not treated immediately, then the accumulated bilirubin spreads to the brain and causes long-term damage. If the buildup of bilirubin is less, then it is termed as mild jaundice, which lends a slightly yellowish tint to the skin and sometimes eyes of the newborn baby. In normal cases, the liver and kidneys eliminate the extra bilirubin from the bloodstream, which leaves the body through urine and stool. In pregnancy, the mother’s body will remove the excess bilirubin for the baby. Post delivery, it takes some days for the liver of the newborn baby to get adjusted at removing the bilirubin from the blood. If the baby is fed every couple of hours, then the mild jaundice commonly goes away on its own after some days. However, if the signs of the jaundice still persists and increase, then the baby needs immediate medical attention.

If there is worsening of the jaundice and treatment is not started, then the bilirubin accumulates and reaches a high level in the blood and this is when kernicterus becomes a serious matter. Some babies may have some health problems, which makes them more prone to have increased levels of bilirubin such as in hemolytic disease, where the mother’s Rh blood factor is not compatible with the baby’s and this results in increased production of bilirubin in the baby. Intestinal blockages in the baby can also make it difficult to remove the bilirubin.

Other factors which increase the chances of the baby developing kernicterus include: Premature birth, polycythemia, sulfonamides, Gilbert’s syndrome, Crigler-Najjar syndrome type-1, G6PD deficiency, problems with breastfeeding, jaundice within the first 24 hours of birth, bleeding or bruises on the baby’s head due to a difficult birth and if the baby has an older sibling who has received phototherapy for jaundice.

Diagnosis of Kernicterus

Medical history and physical exam of the baby is done for diagnosis of kernicterus. Blood tests help in confirming the diagnosis by measuring the bilirubin levels in the baby’s blood. Once the kernicterus has started to develop in the baby, then it means that brain damage has already occurred. So, it is important to treat jaundice as soon as possible before there is a dramatic increase in the bilirubin levels.

Prevention of Kernicterus

Prevention of Kernicterus can be achieved by knowing the symptoms of jaundice in the newborn babies. Kernicterus can also be prevented by getting the baby tested on time and starting early treatment. A transcutaneous bilirubin test is done, if the baby shows signs of jaundice and is still in the hospital, in which a small device is gently placed against the baby’s skin for checking the bilirubin levels. A blood test can also be done to check the bilirubin level of the baby. Phototherapy or light therapy is started as treatment for a baby with an increased bilirubin level. For very mild cases, treatment can be done at home using lights given by the hospital. Treatment of jaundice with phototherapy in newborn is nothing to panic about, as it does not mean that the baby will have brain damage. Phototherapy is done to prevent the bilirubin from increasing to a dangerous level.

It is important to feed the baby every 2 to 3 hours. This will help in passing the bilirubin out of the body through stool and urine. Before getting discharged from the hospital it is important to get a well-baby check-up done. Jaundice in newborns in often at its worst at day 5, therefore it is important to consult the pediatrician within the first 5 days of the child’s birth.

Medical attention should be sought immediately if there is worsening of the jaundice and if the skin on the baby’s arms, tummy or legs starts getting yellow. The whites of the baby’s eyes should also be checked for yellowing. Immediate medical help should be sought if the baby is looking jaundiced, is sleeping a lot, not feeding, is difficult to wake or becomes very fussy.

Treatment of Kernicterus

As of now, there is no effective treatment for completely reversing the damage of kernicterus. Immediate treatment for Kernicterus helps in preventing the worsening of the brain damage. Treatment for Kernicterus starts with phototherapy. Intravenous fluids are given to maintain adequate hydration. The baby may also need tube feedings where a tube is placed down the throat of the baby, which passes into the stomach. Blood test to determine the bilirubin levels are done and also to find out the baby’s blood group in case the baby needs an emergent blood transfusion. Blood transfusion helps in eliminating the excess bilirubin from the baby’s blood.

Long-term treatment for kernicterus and the resulting brain damage depends on the type of damage and the impairments the child has. Treatment for Kernicterus consists of speech therapy, physical therapy and special education. Some patients have had some benefit from deep brain stimulation. Medicines such as clonazepam, baclofen and artane can be prescribed for managing movement disorders, as a result of kernicterus. Hearing aids and cochlear implants also have known to improve the hearing loss, which occurs with kernicterus. Proton pump inhibitors can be prescribed for acid reflux.

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