15.8 Biochemistry: Jaundice Flashcards
What must the concentration of bilirubin in plasma exceed to be visible?
35 micromolar (three times the usual value)
What happens when red blood cells have completed their lifespan?
Macrophages split Hb into haem and globin
What creates biliverdin?
Haem oxygenase in macrophages and liver creates biliverdin, iron and carbon monoxide
What reduces biliverdin to bilirubin
The cytosolic enzyme biliverdin reductase
What type of bilirubin is generated?
Macrophages generate unconjugated (indirect) bilirubin
How much bilirubin is produced each day?
4mg/kg (majority from RBC, some from myoglobin/cytochromes)
What will we see in FBC of jaundiced patients?
Elevation of ALT, AST, GGT, ALP
What is some pathology associated with sepsis? (5)
Billary cirrhosis Pancreatitis Coagulophathy Renal failure Liver failure
What is infection of the common bile duct called?
Cholangitis
What do newborns not produce enough of (resulting in jaundice sometimes)?
Ligandin (and UDPGT)
What do we find in haemolytic jaundice (pre-hepatic)?
High unconjugated bilirubin
Decreased plasma haptoglobins
Increased urobilinogen
Why does neonatal jaundice occur?
Increased haem catabolism
Immaturity of the liver in bilirubin conjugation and excretion
What is the defect in Gilbert’s syndome?
Decreased conjugation/uptake of bilirubin (mild fluctuating jaundice)
What is the defect in Crigler-Najjar syndrome?
Absence of conjugating enzyme, severe unconjugated hyperbilirubinaemia
What is Dubin-Johnson a lack of?
CMOAT
