Jaundice Flashcards
What are reticuloendothelial cells?
macrophages which are responsible for the maintenance of the blood, through the destruction of old or abnormal cells
What is the role of reticuloendothelial cells?
take up red blood cells and metabolise the haemoglobin present into its individual components; haem and globin
What is globin broken down into?
amino acids which are subsequently recycled
What is haem broken down into?
iron and biliverdin, a process which is catalysed by haem oxygenase
What happens to the iron and bilverdin?
- iron gets recycled
2. biliverdin is reduced to create unconjugated bilirubin
What happens to the unconjugated bilirubin in the bloodstream?
binds to albumin to facilitate its transport to the liver
What happens to unconjugated bilirubin in the liver?
glucuronic acid is added to unconjugated bilirubin by the enzyme glucuronyl transferase forming conjuagted bilirubin
What happens to the conjugated bilirubin?
- it is soluble
- excreted into the duodenum in bile.
What happens to the conjugated bilirubin in the colon?
colonic bacteria deconjugate bilirubin and convert it into urobilinogen
What happens to 80% of urobilingoen?
- oxidised by intestinal bacteria and converted to stercobilin and then excreted through faeces
- stercobilin which gives faeces their colour
What happens to 20% of urobilinogen?
reabsorbed into the bloodstream as part of the enterohepatic circulation and taken to liver and some to kidneys
What happens to the urobilingoen in the kidneys?
oxidised further into urobilin and then excreted into the urine
What are the pre-hepatic causes of jaundice?
- Haemolysis
2. Gilberts syndrome
What is gilberts syndrome?
UDPGT not effecting as usual at conjugating bilirubin (common)
What are the signs of pre-hepatic jaundice?
normal urine or dark in haemolysis
What type of bilirubin is there in pre-hepatic jaundice?
unconjugated
What levels are raised in pre-hepatic jaundice?
only bilirubin
What are the causes of hepatocellular jaundice?
- Hepatitis: viral, alcoholic, AI, drug
- Hepatocyte damage/hepatic picture
- Cirrhosis
What do blood tests show in hepatocellular jaundice?
Raised AST/ALT
What are causes of obstructive jaundice?
- Liver mass
- Gallstone
- PBC/PSC
- Pancreatic cancer
- Cholangiocarcinoma/GB cancer
- Drug (ileus)
What type of bilirubin is common in obstructive jaundcie?
conjugated bilirubin
What are the signs in obstructive/cholestasis jaundice?
- Dark urine (conj bilirubin going into urine)
- pale stools (lack of stercobilin)
- pruritus (bile salts into circulation)
What are blood test results in obstructive jaundice?
- Raised ALP/GGT
2. Bile duct damage/obstructive picture
Why does urine turn dark>
when conjugated bilirubin (which is dark) gets into it, i.e., when there is some form of hepatocellular or post-hepatic jaundice
Why is there itching in obstructive jaundice?
bile salts produced in the liver are also blocked from entering the duodenum so they leak into the circulation and causing itching (pruritus), which make be accompanied by scratch marks
What are symptoms of Gilbert’s?
healthy just turn jaundice in times of stress
Where is bile produced?
hepatocytes in the liver
Where is bile stored?
travels via hepatic ducts to gallbladder
How does Bile enter the small intestine?
contractions of the gallbladder facilitate delivery of bile into the duodenum through the Ampulla of Vater
What is the main function of bile?
emulsify fats to allow digestion and absorption – a lack of bile salts will therefore cause malabsorption of lipids which includes fat soluble vitamins such as ADEK
What is the anatomical duct situation?
- left and right hepatic ducts fuse to form common hepatic duct
- common hepatic duct fuses with cystic duct (that comes from gallballder) to form the common bile dict
What does the common bile duct fuse with?
fuses with the main pancreatic duct which carries other enzymes needed for digestion and this flows into duodenum
What are causes of post-hepatic Jaundice?
- Gallstones
- Cholangitis
- Pancreatic cancer
- Bile duct cancer
- PBC/PSC
