L08 - Jaundice Flashcards
What is bilirubin?
A yellow compound that occurs in the normal catabolic haem breakdown pathway in vertebrates
What can an elevated level of bilirubin indicate?
Liver damage or disease - liver isn’t clearing bilirubin properly
What would you expect to happen to serum albumin levels when liver disease is present?
They would decrease
What is jaundice?
Yellow discolouration of the skin, eye and other tissues due to a build up of BILIRUBIN in tissue fluids and bloodstream
What can cause neonatal bilirubin?
Delays in clearance of bilirubin from red cell breakdown
What proteins could you test for in a liver function test?
- Bilirubin
- Liver enzymes (AST/ALT)
- Hepatobiliary enzymes (gGT, alkaline phosphatase)
- Albumin
- Total protein
What would you expect to happen to AST/ ALT when liver disease is present?
Increased
- but could also mean dmg to another organ that prod it such as heart or kidneys
What other things could you test for to indicate liver disease (not in liver function test????) - not sure
- Auto antibodies
- Haematology
- Viral markers
- Metabolic indicators
- Tumour markers
How is bilirubin produced?
Product of haem catabolism From: - RBC - Myoglobin - Cytochromes - Peroxidases
Which cells produce bile and how much is produced per day?
0.5L prod per day by hepatocytes
What is bile and its function?
- Contains bile acids
- Involved in emulsification of fat in SI
Fat soluble vit uptake (A, D, E, K) - Many waste products (bilirubin) are eliminated from body by secretion into bile –> elim in faeces
- Excretion of some substances which can’t be cleared by kidneys; cholesterol, bilirubin
Where is bile stored?
Stored and concentrated in the gallbladder in between meals when no fat needs to be digested (approx 100ml)
Approximately how many times is bile recycled in a day and why?
6 - 8 times per day
- To recycle bile salts so that they can be used again
What is the enterohepatic cycle?
Substances metabolised in liver, excreted into the bile and passed into the intestinal lumen, they are then reabsorbed across the intestinal mucosa and returned to the liver VIA PORTAL CIRC
What stimulates bile secretion?
Cholecystokinin (CCK) secreted by cells of upper SI, stimulates the gallbladder to contract and release stored bile into the SI
What are the stages of liver failure?
- Inflammation - deposits of fat lead to liver enlargement (fatty liver disease - build ups of fat in liver)
- Liver fibrosis - scar tissues begin to form
- Cirrhosis - loss of liver cells and irreversible liver scarring (growth of CT destroys liver cells)
- End-stage liver disease (ESLD)
- Liver cancer
How much excess does total bilirubin in serum need to be to indicate jaundice?
2mg/ml
- Doesn’t necessarily indicate liver disease
- Depends on country/ practice
What is pre-hepatic disease? (Possible causes?)
- Not related to liver
- Haemolytic anaemia which causes excess haem breakdown
- Acc of unconjugated bilirubin
What is intra-hepatic disease? (Possible causes?)
- Originates within the liver (liver condition)
Bilirubin recycling pathway is abnormal - Leading to elevated bilirubin in circ
- Can be caused by disease, infection, drug use, genetic abnormalities, hormonal effects
- Cholestasis
What is extra-hepatic disease? (Possible causes?)
Blockage/ smth after liver that has already conjugated bilirubin
- Extrahepatic biliary tract obstruction - blockage of normal flow of bile from liver to intestinal tract
- Cancer of pancreas, bile duct or intestine
- Cholestasis
How could you distinguish between intra/pre/extra - hepatic disease?
Measure whether the bilirubin has been conjugated or not
What is cholestasis?
The red formation or secretion of bile or extrahepatic biliary obstruction
- Decrease in bile flow due to impaired secretion by hepatocytes or obstruction to bile flow
What are some causes as to why a patient could be diagnosed with jaundice and not liver disease?
- Pre-hepatic
- Intra-hepatic
- Extra-hepatic
Where is bilirubin prod and what are the cells collectively known as?
- Mainly in spleen (macrophages)
- Liver (Kupfer cells)
- Renal tubular cells
- All over body by macrophages
- Collectively known as RETICULOENDOTHELIAL SYSTEM
What is Gilbert’s syndrome?
A mild liver disorder that does nor properly process bilirubin
Will the bilirubin be conjugated or unconjugated in pre-hepatic jaundice?
Unconjugated
Will the bilirubin be conjugated or unconjugated in intra-hepatic jaundice?
Conjugated or unconjugated
Will the bilirubin be conjugated or unconjugated in extra-hepatic jaundice?
Conjugated
What disease other than Gilbert’s syndrome could cause high levels of bilirubin?
Sickle cell anaemia
- Sickle RBC broken down after 10-20 days rather than the normal 120 days
How can Gilbert’s syndrome be passed?
- Offspring
- It is a genetic mutation (autosomal recessive) of the UGT1A1 gene
- Cannot be trasmitted by human-human contact
What are the different types of gallstones?
- Cholesterol
- Pigment
- Mix of both cholesterol and pigment
