Hereditary unconjugated hyperbilirubinemia vs Hereditary conjugated hyperbilirubinemia
How to tell Hereditary unconjugated hyperbilirubinemia and Hereditary conjugated hyperbilirubinemia apart when a board question makes them look alike.
Gilbert/Crigler-Najjar are unconjugated conjugation defects; Dubin-Johnson/Rotor are conjugated transport defects.
Side by side
Gilbert causes mild intermittent unconjugated jaundice during stress or fasting; Crigler-Najjar causes severe unconjugated bilirubin from absent or very low UGT activity.
Dubin-Johnson and Rotor cause predominantly conjugated nonhemolytic jaundice with otherwise benign course and usually normal liver enzymes.
Reduced bilirubin glucuronidation leaves bilirubin unconjugated, albumin-bound, and not water soluble.
MRP2 canalicular efflux defects in Dubin-Johnson or impaired hepatocyte reuptake in Rotor let conjugated bilirubin accumulate.
Indirect bilirubin elevation without urine bilirubin supports Gilbert or Crigler-Najjar physiology.
Direct bilirubin elevation with urine bilirubin supports Dubin-Johnson or Rotor; black liver pigment points Dubin-Johnson.
The trap
All are hereditary jaundice syndromes with normal enzymes, so bilirubin fraction and urine bilirubin are decisive.
The repair move
For inherited jaundice, split the bilirubin first: indirect means conjugation problem; direct means transport/storage problem.
Try a free question
CoreA young adult has mild intermittent scleral icterus during fasting and illness. Liver enzymes are normal, hemolysis testing is negative, and bilirubin is mostly unconjugated. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Gilbert syndrome. Mild intermittent unconjugated hyperbilirubinemia with normal enzymes and stress triggers is Gilbert syndrome.
Why the other choices are tempting
- B. Dubin-Johnson causes predominantly conjugated hyperbilirubinemia and may have dark liver pigment.
- C. Rotor causes predominantly conjugated hyperbilirubinemia without black liver pigment.
- D. Biliary obstruction causes conjugated hyperbilirubinemia with cholestatic clues.
- E. Acute viral hepatitis should raise aminotransferases and systemic hepatitis clues.
Flashcards
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What bilirubin fraction points to Gilbert syndrome?
Mild unconjugated hyperbilirubinemia, often triggered by fasting or illness, points to Gilbert syndrome.
What makes Crigler-Najjar more dangerous than Gilbert?
Much lower UGT activity causes severe unconjugated bilirubin with neurologic toxicity risk, especially in type I.
Quick answers
What is the fastest way to tell Hereditary unconjugated hyperbilirubinemia from Hereditary conjugated hyperbilirubinemia?
Gilbert/Crigler-Najjar are unconjugated conjugation defects; Dubin-Johnson/Rotor are conjugated transport defects.
What is the key clue for Hereditary unconjugated hyperbilirubinemia?
Gilbert causes mild intermittent unconjugated jaundice during stress or fasting; Crigler-Najjar causes severe unconjugated bilirubin from absent or very low UGT activity.
What is the key clue for Hereditary conjugated hyperbilirubinemia?
Dubin-Johnson and Rotor cause predominantly conjugated nonhemolytic jaundice with otherwise benign course and usually normal liver enzymes.
What is the common trap with Hereditary unconjugated hyperbilirubinemia vs Hereditary conjugated hyperbilirubinemia?
All are hereditary jaundice syndromes with normal enzymes, so bilirubin fraction and urine bilirubin are decisive.