Liver failure and Jaundice Flashcards
What is bilirubin?
Yellow pigment from the breakdown of haemoglobin
H2O insoluble
Where is most bilirubin created or released?
Spleen
Where RBC destruction and repackaging happens
How does bilirubin get to liver
Albumin binds to bilirubin, carries in blood to liver. Albumin release
Bilirubin enters hepatocyte.
How does bilirubin become soluble
Conjugation (joining) to glucaronic acid using UDPGT from smooth ER
So now bound and now called
Diglucoronide billirubin/conjugated billirubin
So more soluble
What is the total BR?
Free unconjugated and conjugated bilirubin
What happens to conjugated bilirubin?
Transported across concentration gradient into bile canaliculi to GIT
What is urobilinogens?
Formed by action of gut bacteria - H2O soluble colourless derivative of bilirubin
Why is poo brown
In colon, bilirubin undergoes reduction by gut bacteria to stercobilinogen
Oxidised to stercobilin
Which is brown
So poo is brown
What is jaundice?
Excess bilirubin in the blood which is >34-50microM/L
What is cholestasis?
Slow or sluggish bile flow
Normally results in jaundice but jaundice doesn’t necessarily mean cholestasis
What three groups are the causes of jaundice divided into?
Pre-hepatic
Hepatic
Post-hepatic
What causes pre-hepatic jaundice?
Before reaches liver - too much bilirubin being produced too fast Haemolysis - too fast RBC death Massive tranfusion Haematoma resorption Ineffective erythropoiesis
What is hepatocellular jaundice
Normal bilirubin entering liver
There is liver disease/illness killing hepatocytes
Less conjugation
Less secretion
What causes hepatocellular jaundice
Anything causing liver failure paracetamol overdose Chronic liver failure - viral hepatitis B/C alcohol sepsis in liver drugs
How to distinguish between hepatic and pre-hepatic jaundice
pre-hepatic -> liver is normal but in hepatic the liver is dying
What is post hepatic jaundice aka obstructive
Liver fine
Bilirubin amount fine
Physical obstruction of bile flow into duodenum so less bilirubin enter gut so bilirubin levels will increase
What are causes of post hepatic jaundice aka obstructive
Gall stones
Cancer eg gall bladder/bile duct/tumour on dead of pancreas pressing on duodenum
Will the majority of bilirubin be conjugated or unconjugated in pre-hepatic, hepatic and post hepatic jaundice?
Pre-hepatic unconjugated
Hepatic unconjugated
Post-hepatic conjugated
What happens to poo and urine in obstructive jaundice
Less brown bc less bilirubin so less stercobilogen
pale
Urine dark, as bilirubin tries to get out by kidneys
What is the commonest hereditary cause of increased bilirubin
Gilbert’s Syndrome
What is Gilbert’s syndrome caused by
Elevated unconjugated bilirubin in blood stream
Caused by less glucuronidation activity of the enxyme UDPGT-1A1 so conjugates bilirubin slower
No serious consequences
What is liver failure?
Amount of hepatocytes destroyed more then hepatocytes regenerated
What are examples of stuff livers do?
Detoxificaition
Glycogen storageProduction of clotting factors
Immunological function and globulin production
Maintenance of homeostasis - albumin making
