Neonatal jaundice, also called hyperbilirubinemia, occurs in around 60% of full-term newborns and 80% of premature newborns. It is detectable by a yellowish tinge to the skin and the whites of the eyes caused by a buildup of bilirubin in the blood. Bilirubin is a yellowish waste product that occurs when red blood cells break down.
It is quite common in newborns with hemolytic disease of the fetus and newborn (HDFN), as the baby’s liver is too immature to eliminate the bilirubin independently. If treatment is delayed or ineffective, jaundice can develop into kernicterus, which can lead to serious long-term neurological effects and even death.
What is HDFN?
Hemolytic disease of the fetus and newborn (HDFN) is an immune-mediated red blood cell disorder that occurs when a baby’s RBCs break down quickly, which is called hemolysis. HDFN is caused by a mismatch between a mother’s and her baby’s blood type (A, B, AB, or O) or Rhesus (Rh) factor (Rh-positive or Rh-negative) during pregnancy.
How is jaundice diagnosed and treated?
Jaundice is a common symptom in newborns affected by HDFN. At times, it resolves with no intervention. Often, phototherapy is required to break down the bilirubin in the blood so the baby can eliminate it. It can be followed by exchange transfusions if bilirubin levels don’t fall or stabilize in the newborn. Bilirubin levels are closely monitored, and tested every four to six hours with blood tests or with a bilirubinometer, which identifies the bilirubin levels by shining a light onto the baby’s skin.
How does kernicterus occur?
Kernicterus or bilirubin encephalopathy is a life-threatening neurological complication of jaundice that is diagnosed late or left untreated. It occurs when the unconjugated bilirubin levels continue to rise and cross 25 mg/dL in the blood. The bilirubin then crosses the blood-brain barrier and enters the neuronal and glial membranes.
It can cause long-term brain damage, hearing loss, learning disabilities, cerebral palsy, poor development of tooth enamel and visual disabilities, such as a permanent upward gaze.
What are the symptoms of kernicterus?
Newborns with kernicterus often are irritable, lethargic and have less muscle strength, with other early symptoms including poor feeding, no startle reflex, a high-pitched cry and vomiting. In the initial stages of kernicterus, the prognosis remains positive if rapid medical intervention reduces the bilirubin levels.
As the condition progresses, the newborn may experience muscle spasms or seizures, with backward arching of the neck. The neurotoxicity of bilirubin causes damage to the brain and the central nervous system that is irreversible.
How is kernicterus treated?
Urgent treatment is required to reduce bilirubin levels to prevent neurotoxicity. Kernicterus is treated with the same therapy as jaundice–exchange transfusion therapy, phototherapy and intravenous immunoglobulin (IVIG), particularly in the case of HDFN-affected babies.
