Jaundice Flashcards
What is the purpose of bile?
emulsification of fat in the intestine
Far soluble vitamin uptake
excretion of cholesterol and bilirubin
Stages of liver damage
Healthy Liver
Fatty Liver- deposits of fat- liver enlargement
Liver Fibrosis- scar tissues forms
Cirrhosis- growth of connective tissue destroys liver cells
What is jaundice?
yellow discolouration of the skin, eye and other tissues
build of of bilirubin in tissue fluids and bloodstream- in excess 2mg/ml
Why is jaundice not necessarily liver disease
neonatal jaundice
What is bilirubin a product of?
Haem catabolism
From RBC, myoglobin, cytochromes, peroxidase
How is bilirubin transported to liver?
Carried by albumin as it is insoluble
How does bilirubin enter the liver?
Active transport across the liver membrane
What happens to bilirubin in the liver?
it is conjugated with glucuronic acid by UDP glucoronyltransferrase
What happens to bilirubin after it is conjugated?
Bilirubin becomes water soluble and it is excreted into bile
Where is bile excreted into?
duodenum
What happens to bilirubin in the intestinal tract?
It is metabolised by b-glucuronidase in the gut ( bacterial or epithelial cells) to form unconjugated bilirubin
What happens to the unconjugated bilirubin in the gut
Chemical reduction into urobilinogen
What happens to urobilinogen?
Some is reabsorbed and sent back to the liver
some is excreted in urine
some is converted into stercobilinogen by bacteria
What are the three main causes of jaundice
Prehepatic
Intrahepatic
Extrahepatic
What is heamolytic anaemia?
red cell destruction
What is Paroxysmal nocturnal haemaglobulinurea (PNS)?
genetic, fragile RBCs
What are the two main categories of pre-hepatic jaundice
Haemolysis
Gilbert’s syndrome
What is sickle cell disease?
Genetic, varient forms of Hb present
What are the three main examples of haemolysis
Haemolytic anaemia
Paroxysmal nocturnal haemoglobulinurea (PNS)
Sickle cell disease
What other liver symptoms are present in anaemias
gallstones, increased bilirubin, dark urine hepatomegaly, splenomegly elevated AST/ALT thrombosis iron overload hepatic thrombosis coagulation deficit Altered MRI signal
What is the treatment for sickle cell disease?
Agressive manual exchange RBC transfusion to reduce HbS
What is Gilbert’s
mutation in UDP-glucoronyl transferase 1 gene
leads to deficiency in enzyme to conjugate bilirubin
therefore elevated unconjugated bilirubin
What is the typical presentation of pre-hepatic jaundice
increased unconjugated bilirubin Normal AST/ ALT Normal ALP/ Gamma GT Bilirubin is not found in urine urobilinogen is found in urine normal colour stools and urine
What is required for a differential diagnosis of gilbert’s?
Exclude haemolysis and other liver diseases
What is the cause of neonatal jaundice?
Delays in clearance of bilirubin from red cell breakdown
What is the treatment for neonatal jaundice?
phototherapy
What are the hepatic cause for jaundice?
Liver disease Viral hepatitis Toxic-alcohol Cirrhosis Liver injury- intrahepatic cholestasis
What are the causes of intrahepatic cholestasis?
cancer
destruction of bile ductules due to drugs or autoimmunity
secondary to systemic injury, pregnancy, drug toxicity
What is the typical presentation of hepatic jaundice?
Raised AST/ALT Mild increase ALP/ gamma GT increased conjugated bilirubin if complete bile duct obstruction- urobilinogen is not found in urine pale stools dark urine
