Kernicterus

Also known as Hyperbilirubinemia or Bilirubin Encephalopathy

Kernicterus is a rare complication of childbirth that occurs in the newborn, who has a severely elevated bilirubin level. Hyperbilirubinemia results in jaundice or yellowing of the skin and eyes. If very severe and left untreated, the problem causes brain damage in the form of Kernicterus.

The cause of Kernicterus is an extremely elevated bilirubin level. Bilirubin is a pigment, which is yellow in color and which builds up if the liver can't process the breakdown product of red blood cells and hemoglobin. The body begins to build up the bilirubin and the end result is a yellow child. If the bilirubin count is very high for a period of time, the bilirubin builds into the brain, resulting in brain damage, which can be permanent.

Kernicterus is usually a problem that occurs in the first week of life but in can be seen up to three weeks of age. It is especially common in infants who have Rh incompatibility with the mother. This can lead to a condition known as hydrops fetalis, a sometimes fatal condition in which the infant makes large amounts of antibodies against maternal red blood cells and the red blood cells are broken up quickly and dangerously. Kernicterus is usually seen in babies who are sick or have some kind of blood condition but it can be seen in normal infants as well.

The symptoms of kernicterus include extreme yellowing of the skin (jaundice) as well as an absent startle reflex, marked lethargy or sleepiness and poor sucking reflex or inability to nurse. This is seen in the early stages of kernicterus. If the kernicterus is allowed to become more moderate, there is often an arched back with a hyper extended neck and a high pitched cry. The soft spot or fontanelles are bulging and there can be seizure behavior. If the kernicterus is allowed to become severe or end stage, there is often hearing loss of the high frequencies first, mental deficiency, speech difficulties, muscle rigidity, and various movement disorders.

Doctors can do various tests to determine the presence of neonatal hyperbilirubinemia and kernicterus. The hyperbilirubinemia is checked for in a blood test, which will show a hemoglobin level of about 20 mg/dL or more. This usually persists, in spite of light therapy and other therapies. The doctor can also do a physical examination to see if there are signs that the elevated bilirubin is causing brain injury or if it is just causing minor symptoms such as lethargy. The bilirubin levels are often tested at regular intervals to see if it is increasing, decreasing or responding to therapy.

There are a couple of good ways to lower the bilirubin level and reduce the risk of full blown kernicterus. This involves phototherapy. Light is used to manage the levels of bilirubin in the bloodstream and can come in the form of a light box that the baby sleeps in or as a light blanket or light vest that goes up against the skin and shines a blue light onto the skin.

In severe cases, the infant can receive an exchange transfusion, which exchanges the bad blood along with the elevated bilirubin with normal blood that has normal levels of bilirubin in it. It rapidly decreases the bilirubin within the bloodstream. The treatment used depends on how old the baby happens to be and on the level of absolute bilirubin in the blood.

The outcome of kernicterus is guarded if it develops into its later stages. The outlook can mean that the infant has permanent brain injury or even death.

Prevention of kernicterus depends on checking and treating hyperbilirubinemia when it is in its early stages and before kernicterus can happen. If there is any sign of jaundice within the first day of life, a bilirubin should be performed and light therapy started if the infant has an elevated bilirubin. If the bilirubin is markedly elevated, both light therapy and exchange transfusions should begin before brain damage has had a chance to occur.