A newborn dies three days after birth; an autopsy shows bilirubin deposition in the brain. What is the most likely cause of this condition?

The presence of bilirubin deposition in the brain of a newborn, particularly within a few days after birth, suggests a significant buildup of unconjugated bilirubin, leading to a condition known as kernicterus. This is often the result of hemolytic disease of the newborn, where an Rh or ABO incompatibility leads to increased hemolysis of red blood cells, causing elevated levels of bilirubin in the bloodstream.

In this condition, the liver of the newborn may not be mature enough to handle the excess bilirubin, resulting in its accumulation. Eventually, this excess bilirubin can cross the blood-brain barrier and deposit in brain tissues, leading to serious neurological damage. This pathophysiological process aligns closely with hemolytic disease of the newborn, making it the most likely cause of bilirubin deposition in the brain in this scenario.

The other options do not typically lead to bilirubin accumulation in the same manner. Biliary atresia involves an obstructive process of the bile ducts that usually results in conjugated hyperbilirubinemia, rather than the unconjugated form associated with hemolysis. Cyanotic congenital heart disease can cause hypoxia and other systemic issues but is not directly related to bilirubin deposition. Respir