Causes Of Kernicterus In Newborns, Symptoms And Treatment
Lethargy and floppy muscles are some signs of this condition that causes yellowish skin.
Specialty: PediatricsExperience: 6 yearsElham Raker is a board-certified pediatrician and parent coach. Over the span of her six-year career, she has worked in different clinical settings, including outpatient, urgent care, hospital care, emergency room, and home-based care. She has two teenage children.
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Kernicterus in newborns is a condition that is characterized by jaundice, which is the yellowish discoloration of the eyes and the skin. It is due to high bilirubin levels. If untreated, severe jaundice may cause brain damage (1).
The condition of kernicterus is common in infants. It is also called bilirubin-induced neurological damage or bilirubin encephalopathy. Early detection and treatment of jaundice could prevent kernicterus and the serious complications that follow (2).
Read on to know more about the causes, symptoms, complications, and treatment of kernicterus in babies.
How Does Jaundice Cause Kernicterus?
The natural breakdown of the body’s red blood cells forms a compound called bilirubin (3). The liver processes bilirubin and the compound is excreted through urine and stool eventually. Babies have excess bilirubin since their red blood cells disintegrate faster than their livers can’t process bilirubin, causing jaundice. Jaundice leads to kernicterus when the total serum bilirubin level exceeds 25mg/dL.
Untreated jaundice may lead to kernicterus in two to five days after birth. Infants with a total serum bilirubin level less than 25mg/dL may also develop kernicterus. About one in seven infants with bilirubin levels higher than 30mg/dL will develop kernicterus (2).
Recent medical advancements have made kernicterus cases rarer than before, especially in some countries. For instance, according to the NHS, kernicterus affects about 1 in 100,000 babies in the UK (4) (5).
Symptoms Of Kernicterus In Newborn Babies
The following are the common initial symptoms of kernicterus in babies (4) (6).
- Lethargy
- Poor feeding
- Irritability
- High-pitched cry
- Fever
- Apnea (pauses in breathing)
- Floppy muscles (muscle hypotonia)
- Absence of certain primitive reflexes
As the disease progresses, there is an excess accumulation of bilirubin in the brain, causing tissue damage. It could lead to the following severe symptoms (5).
- Seizures
- Bulging soft spot
- Hearing loss
- Respiratory distress
- Excessive muscle stiffness
- Problems with body movement and control
- Arching of the back and neck
Risk Factors For Kernicterus
The following conditions may increase the bilirubin levels in the baby’s body, causing severe jaundice, which could proceed to kernicterus eventually (7) (8).
- Premature birth: Babies born before 37 weeks of gestation may not have fully developed livers. The immature livers may be unable to remove excess bilirubin efficiently.
- Blood type: Babies of women with O blood type or Rh-negative blood factors are at a higher risk of having excessive bilirubin.
- Blood group incompatibility: If the baby and mother have different blood groups, the newborn’s blood cells could be damaged by maternal antibodies. Rapid breakdown of red blood cells could lead to excess bilirubin. This condition is known as hemolytic disease.
- Bruising during birth: A large amount of bruising during birth increases the breakdown of the red blood cells, contributing to the increasing bilirubin levels.
- Family history: The parents may pass certain genetic anomalies, leading to disorders that cause the breakdown of the baby’s red blood cells.
Diagnosis Of Kernicterus In Babies
The doctor may check for the presence of kernicterus periodically if the baby has been diagnosed with jaundice already. The following tests help in knowing if the bilirubin levels are suggestive of kernicterus (4).
- Physical examination: Check for the signs and symptoms, such as abnormal cry and poor primitive reflexes, which are suggestive of brain damage due to kernicterus.
- Light meter test: A doctor or nurse will place a light meter on the baby’s head to determine the transcutaneous bilirubin (TcB) level. If the reading is high, a blood test may be advised to determine kernicterus.
- Blood test: The nurse will draw a blood sample from the baby’s heel to check for the total serum bilirubin (TSB) levels. If the TSB levels are high, kernicterus is confirmed.
Treatment For Kernicterus In Babies
Treatment is decided on factors, such as the baby’s age in hours, baby’s gestational age, symptoms, and bilirubin levels. Once jaundice progresses to kernicterus, the baby experiences some brain damage already. Therefore, the treatment strategies focus on reducing the bilirubin level and preventing brain damage from progressing.
The following treatment methods could be considered to reduce bilirubin levels.
- Phototherapy: Intense fluorescent light is focused on the baby’s bare skin. The baby is dressed only in a diaper, and the eyes are shielded. The light helps in the decomposition and excretion of the excess bilirubin. During the treatment, the doctors test bilirubin levels every four to six hours until the bilirubin levels begin to drop and then every six to 12 hours until the treatment is complete.
- Transfusions: Blood transfusion is the second level of treatment for more severe cases. In this procedure, a little bit of blood is removed and is replaced with donor blood. Doctors test bilirubin levels two hours after the treatment and may perform another transfusion if the levels are not within the favorable range.
Complications Of Kernicterus
Babies with kernicterus may develop the following complications (5).
- Cerebral palsy
- Hearing loss
- Learning deficit
- Involuntary twitching of body parts
- Inability in maintaining normal eye movement
- Problems with teeth development
Prognosis Of Babies With Kernicterus
Kernicterus is a serious and life-threatening condition. The outcome usually depends on how soon the treatment was commenced. If kernicterus is diagnosed early and the treatment is started sooner, the neurological effects are minor. However, they may still have problems with motor skills as they grow in age (7). The baby’s healthcare provider may suggest long-term strategies to minimize complications or lasting effects of kernicterus. Kernicterus is rare as jaundice is usually caught early on during the hospital stay avoiding the progression to kernicterus.
Frequently Asked Questions
1. What are the stages of kernicterus?
Clinical manifestations of kernicterus can be in three stages or phases. In phase one, poor feeding, reduced alertness, and hypotonia are observed in babies. They can progress into phase two with hypertonia of extensor muscles. If left untreated, babies can develop long-term neurological deficits in the second phase of the disease. Phase three can be associated with hypotonia in infants aged more than a week (9).
2. Which part of the brain does kernicterus affect?
The neurological deficits and problems may vary depending on the affected brain area. Brain areas such as basal ganglia, hippocampus, geniculate bodies, and cerebellum can be affected. Cranial nerve nuclei such as oculomotor, vestibular, and cochlear are commonly affected during kernicterus (10).
Kernicterus is brain damage caused by high levels of bilirubin in the blood. Newborns with severe jaundice may develop this complication if it is not managed promptly. However, parental awareness of signs of jaundice such as poor feeding, apnea, and fever could help in seeking early medical care. Further, it is recommended to seek your pediatrician’s opinion if you are concerned about your newborn’s health or notice any symptoms. Timely treatment could help bring down their bilirubin levels and prevent kernicterus in newborns.
Key Pointers
- Kernicterus in newborns is caused due to untreated jaundice.
- Symptoms include lethargy, irritability, poor feeding, floppy muscles, and high-pitched cry.
- Preterm birth, blood group incompatibility with mother, and family history can increase the risk of this condition.
- Doctors may perform physical examination and light meter test to diagnose kernicterus in infants.
References
2. Dinesh K. Reddy and Shivlal Pandey, Kernicterus; National Center for Biotechnology Information
3. Newborn jaundice; NHS
4. Kernicterus in Newborn Babies; Birth Injury Help Center
5. Kernicterus; NHS
6. Kernicterus; National Organization for Rare Disorders
7. Kernicterus; Birth Injury Justice Center
8. Kernicterus; C.S. Mott Children’s Hospital
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