Conjugated hyperbilirubinemia in infancy seen in –a) Choledochal cystb) Extra hepatic biliary atresiac) Crigler – Najjar diseased) Gilbert disease

**Core Concept**
Conjugated hyperbilirubinemia in infancy is a condition characterized by elevated levels of conjugated bilirubin in the blood, which is a type of bilirubin that has been processed by the liver and is typically water-soluble. This condition is often associated with liver dysfunction or bile duct obstruction.

**Why the Correct Answer is Right**
Crigler-Najjar disease is a rare genetic disorder that affects the enzyme responsible for converting unconjugated bilirubin to conjugated bilirubin, leading to a buildup of unconjugated bilirubin in the blood. However, this question asks about conjugated hyperbilirubinemia, which is typically associated with liver dysfunction or bile duct obstruction. The correct answer, **choledochal cyst**, is a congenital anomaly of the bile duct that can cause conjugated hyperbilirubinemia due to bile duct obstruction. This condition is often diagnosed in infancy and can lead to complications such as jaundice, cholangitis, and liver damage if left untreated.

**Why Each Wrong Option is Incorrect**
**Option A:** Choledochal cyst is the correct answer, but Crigler-Najjar disease is a type of unconjugated hyperbilirubinemia, not conjugated.
**Option B:** Extrahepatic biliary atresia is a condition that can cause conjugated hyperbilirubinemia, but it is typically diagnosed in infancy and is characterized by a progressive obstruction of the bile ducts.
**Option C:** Crigler-Najjar disease is a type of unconjugated hyperbilirubinemia, not conjugated.
**Option D:** Gilbert disease is a mild condition that causes unconjugated hyperbilirubinemia, not conjugated.

**Clinical Pearl / High-Yield Fact**
Crigler-Najjar disease is often referred to as a "bilirubin nightmare" due to its severe and potentially life-threatening complications if left untreated.

**Correct Answer:** A. Choledochal cyst