Jaundice Flashcards
Draw and label a diagram that shows the bilirubin pathway
Hb broken down by macrophages when RBC’s die.
The globin released is broken down and reused.
The haem released is converted into bilirubin which is carried by albumin in the blood to the liver.
In the liver, UDP- glucoronyltransferase conjugated the bilirubin by adding glucoronic acid. This makes it water soluble.
This conjugated bilirubin is converted to urobilinogen by b-glucaronidase.
90% of this is excreted in faeces. Stercobilin gives characteristic brown colour.
10% is reabsorbed, bound to albumin. Some is sent back to the liver where the cycle repeats and some is sent to the kidneys where it is excreted in urine. Urobilin gives urine its yellow colour.
What do liver function tests look for?
bilirubin liver enzymes AST/ALT hepatobiliary enzymes albumin total protein
autoantibodies haematology viral markers metabolic indicators tumour markers
What would you expect to happen to albumin levels during liver disease and why?
decrease because the liver produces albumin
Define jaundice
What are the 3 classifications of causes?
yellow discolouration of the skin, sclera and other tissues due to a build up of bilirubin in tissue fluids and bloodstream. in XS of 2mg/ml
prehepatic = unrelated to liver intrahepatic = liver disease posthepatic = after liver e.g. gallstones
Give 2 causes pre hepatic jaundice? Give disease examples
haemolysis e.g. malaria, thallesemia
high levels of unconjugated bilirubin
defect in liver but no liver disease e.g Gilberts’ Syndrome
increased unconjugated bilirubin due to mutation in UDP-glucuronyltransferase
see increased fasting bilirubin, benign
Give 2 causes of hepatic jaundice
Jaundice due to liver injury
- Failure of cellular mechanisms of excretion of conjugated bilirubin e.g. acute/chronic hepatitis or cirrhosis
- Cholestasis or interruption of bile flow as a result of damage to the liver e.g. cancer, autimmune/drug destruction of bile ductules
Compare and contrast the different types of viral hepatitis, in terms of:
- transmission
- acute severity
- chronicity
- vaccine?
A&E = faeces, mild to severe, no chronicity, vaccine B = sex, mild to severe, chronic 30%, vaccine C = blood, very mild, chronic 90%, no vaccine
What is cholestasis?
Accumulation of bile within the liver
What are the 3 causes of post-hepatic jaundice?
gallstones
disease of ducts e.g. cancer, inflammation
compression of ducts e.g. lymph nodes, pancreatic cancer
What colour would the urine and faeces be in a patient with gallstones? Why?
urine = brown, due to presence of unconjugated bilirubin faeces = pale, lack of bilirubin as bile cannot enter GIT
What is the typical person affected by gallstones?
What may they present with?
Fat, Forty, Female, Fertile
biliary colic, sepsis, jaundice, cholangitis
What kind of jaundice may pancreatic cancer cause?
obstructive painless jaundice
growth obstructs the bottom of the common bile duct
What is neonatal jaundice?
What is the cause?
What is the treatment? Why does this work?
When would it lead to concern?
pretty common
Delays in clearance of bilirubin from red cell breakdown
Treated by phototherapy, UV light isomerises bilirubin and makes it water soluble
Concern if persists and is accompanied by pale stool and dark urine because this indicate a hepatic problem
Differntial diagnosis of jaundice: haemolytic, hepatic and obstructive.
- serum conjugated and unconjugated bilirubin
- urine urobiliogen and bilirubin
- faceal urobiliogen
Haemolytic
- normal conjugated, high unconjugated bilirubin
- urine high urobiliogen, no bilirubin
- high faecal urobilinogen
Hepatic
- increased conjugated/unconjugated bilirubin
- urine low urobilinogen, contains bilirubin
- low faecal urobilinogen
Obstructive
- high conjugated, normal unconjugated bilirubin
- urine no urobilinogen, contains bilirubin
- no faecel urobilinogen
