[38] Jaundice Flashcards
What is the normal range of bilirubin?
3-17uM
At what bilirubin level is jaundice visible?
50uM
How is bilirubin produced?
Unconjugated bilirubin (uBR) is produced from the breakdown of haemoglobin by splenic macrophages
What happens to uBR produced by splenic macrophages?
It is converted to conjugated bilirubin (cBR) by BR-UDP-glucuronyl transferase in the liver
What happens to cBR after it has been produced in the liver?
It is secreted in the bile, then converted into urobilinogen
What colour is urobilinogen?
Colourless
What happens to urobilinogen in the GIT?
Some is reabsorbed
The urobilinogen that remains in the GIT is converted to stercobilin and excreted
What colour is stercobilin?
Brown
What happens to the urobilinogen that is reabsorbed into the liver?
It is returned to the liver and re-excreted into bile or urine
What causes pre-hepatic jaundice?
Excess bilirubin production
What can cause excess bilirubin production?
Haemolytic anaemia
Ineffective erythropoiesis
Give an example of something that can cause ineffective erythropoiesis
Thalassaemia
What are the categories of hepatic jaundice?
Unconjugated
Conjugated
What causes unconjugated hepatic jaundice?
Decreased bilirubin uptake
Decreased bilirubin conjugation
What can cause decreased bilirubin uptake?
Drugs
CCF
Give 2 examples of drugs that can cause decreased bilirubin uptake
Contrast
Rifampicin
What can cause decreased bilirubin conjugation?
Hypothyroidism
Gilbert’s
Crigler-Najjar
What causes neonatal jaundice?
Increased production and decreased conjugation of bilirubin
What causes conjugated hepatic jaundice?
Hepatocellular dysfunction
Decreased hepatic bilirubin excretion
What are the categories of causes of hepatocellular dysfunction leading to conjugated hepatic jaundice?
Congenital Infection Toxin Autoimmune Neoplasia Vascular
What are the congenital causes of hepatocellular dysfunction?
Heriditary haemochromotosis
Wilson’s
Alpha 1 anti-trypsin deficiency
What are the infectious causes of hepatocellular dysfunction?
Hepatitis A/B/C
CMV
EBV