Jaundice Flashcards
When can we see jaundice in caucasians?
Bilirubin of about 50
What actually causes jaundice?
High bilirubin levels
What is bilirubin?
Breakdown product of heme from haemoglobin
Why do we breakdown haemoglobin?
To get the iron back from the haem
What blood/urine results with pre-hepatic jaundice give?
High levels of unconjugated bilirubin
No bilirubin in the urine
Why is there no bilirubin in the urine in pre-hepatic jaundice?
Because unconjugated bilirubin is not water soluble so it just stays in the blood.
What are the three stages of bilirubin metabolism?
Hepatic uptake
Conjugation
Excretion
What is the metabolism cycle of bilirubin?
In the blood: unconjugated bilirubin is made as a breakdown of haemoglobin
Unconjugated bilirubin is then taken up by the liver
It is conjugated with glucuronic acid in hepatocytes and excreted into bile duct as conjugated bilirubin
Passed into the gut with the bile
Some conjugated bilirubin is reabsorbed into blood and filtered out by kidneys, making urine dark (urobilinogen)
The rest is excreted in poo as stercobilinogen, making stools brown.
What can cause a rise in unconjugated bilirubin?
Over production - haemolytic anaemia, ineffective erythropoeisis
Impaired hepatic uptake - paracetamol, rifampicin, ischaemia
Impaired conjugation - Gilbert’s
Neonatal jaundice
What type of jaundice do we call it when there is purely a rise in unconjugated bilirubin?
Pre-hepatic
What is Gilbert’s syndrome?
A reduction of bilirubin UDP-gludronyl-transferase activity which is involved in the conjugation of bilirubin. This leads to higher levels of unconjugated bilirubin. It is a benign disease and the only sign is jaundice.
What happens when bilirubin can’t be conjugated?
Unconjugated bilirubin goes into the blood and causes hyperbilirubinaemia.
It cannot go be excreted by kidneys into the urine because it isn’t water soluble.
What are the wee and poo doing in hepatic jaundice?
Urine is dark due to rise in conjugated bilirubin in the blood as the liver is not doing a good job of excreting it to bile ducts.
Poo is still dark as some conjugated bilirubin is in the stools.
What are the causes of hepatic jaundice?
Virus: hepatitis, EBV, CMV Drugs Alcohol Cirrhosis Cancer AIH Leptospirosis Alpha-1-antitrypsin deficiency Wilson's Budd-Chiari Malignancy RHF
What are the most common causes of jaundice in a previously stable patient with cirrhosis?
Sepsis
Malignancy
Alcohol/drugs
GI bleed
