A patient presents with unconjugated hyperbilirubinemia and presence of urobilinogen in urine. Which amongst the following is the least likely diagnosis –
**Core Concept**
Unconjugated hyperbilirubinemia indicates elevated indirect bilirubin, primarily due to increased hemolysis or impaired bilirubin conjugation. Urobilinogen in urine is a sign of intact enterohepatic circulation, suggesting the liver is processing bilirubin but not conjugating it efficiently. The key distinction lies in whether the defect is in bilirubin uptake (hemolysis), metabolism (Gilbert), or conjugation (Dubin Johnson).
**Why the Correct Answer is Right**
Dubin Johnson syndrome is characterized by **hepatocellular dysfunction** with **impaired bilirubin conjugation**, leading to **conjugated hyperbilirubinemia**, not unconjugated. Patients have **elevated conjugated bilirubin** and **negative or low bilirubin in urine** due to reduced excretion. The presence of **unconjugated hyperbilirubinemia** and **urobilinogen in urine** contradicts this diagnosis, making it the least likely.
**Why Each Wrong Option is Incorrect**
Option A: Hemolytic jaundice causes unconjugated hyperbilirubinemia due to increased RBC breakdown and impaired bilirubin conjugation; urobilinogen is excreted in urine.
Option B: Crigler Najjar syndrome involves **severe unconjugated hyperbilirubinemia** due to **defective UDP-glucuronosyltransferase**, leading to high indirect bilirubin and urobilinogen in urine.
Option C: Gilbert's syndrome presents with **mild, intermittent unconjugated hyperbilirubinemia** and **urobilinogen in urine** due to reduced bilirubin conjugation; it is benign and common.
**Clinical Pearl / High-Yield Fact**
In Dubin Johnson syndrome, **conjugated hyperbilirubinemia** is the hallmark, not unconjugated. Always check bilirubin type (conjugated vs unconjugated) to differentiate liver disorders.
✓ Correct Answer: D. Dubin Johnson syndrome