MCQ – 89087

Correct Answer � C Explanation

Correct answer : c  Encephalopathy

• Kernicterus, also termed bilirubin encephalopathy, is defined as a neurological condition associated with severe jaundice and characterized by bile staining of the brain, particularly of the basal ganglia, pontine nuclei, and dentate nuclei in the cerebellum. Kernicterus (German: kern, nucleus) is essentially confined to newborns with severe unconjugated hyperbilirubinemia, usually related to erythroblastosis fetalis. 

• The bilirubin derived from the destruction of erythrocytes and the catabolism of the released heme is not easily conjugated by the immature liver, which is deficient in glucuronyl transferase. 

• The development of kernicterus is directly related to the level of unconjugated bilirubin and is rare in term infants when serum bilirubin levels are below 20 mg/ dL. Premature infants are more vulnerable to hyperbilirubinemia and may develop kernicterus at levels as low as 12 mg/dL.

• Bilirubin is thought to injure the cells of the brain by interfering with mitochondrial function. 

• Severe kernicterus leads initially to loss of the startle reflex and athetoid movements, which in 75% progresses to lethargy and death. Most surviving infants have severe choreoathetosis and mental retardation; a minority have varying degrees of intellectual and motor retardation.

• Exchange transfusions may keep the maximum serum bilirubin at an acceptable level. However, phototherapy, which converts the toxic unconjugated bilirubin into isomers that are nontoxic and excreted in the urine, has greatly reduced the need for exchange transfusions. 

• The other choices are not complications of untreated hyperbilirubinemia in newborns.