Liver disease CPC Flashcards
What does the portal triad consist of?
Hepatic vein, artery, bile duct
What is the Space of Disse?
The spaces between the hepatocytes and the endothelium (discontinuous organisation) of the sinusoids meaning that the blood comes into contact with the all the liver enzymes
What is Zone 1 damage and what substances cause it?
Periportal damage, caused by directly hepatotoxic substances
What is Zone 3 damage and what substances cause it?
Centrilobar damage, caused by metabolised hepatotoxic substances i.e. those that require bioactivation. Hypoxic damage as most oxygen lost by the time the blood reaches Zone 3
In which zone are the most metabolically active cells in the liver?
Zone 3
ALP rises more when which zone is damaged? Why?
Zone 1 due to proximity to bile ducts
What is Zone 2 damage?
Midzonal
Name 2 substances that cause Zone 1 damage
Iron salts, white phosphorus
Name 3 substances that cause Zone 2 damage
Furans, ngaione (myosporum spp.), beryllium
Name 4 substances that cause Zone 3 damage
Acetaminophen, aflatoxin, microcystin, ricin
How do you measure the split bilirubin? (conjugated and unconjugated)
van den Bergh reaction
Direct reaction to measure conjugated BR
Indirect reaction to measure unconjugated BR: add methanol which completes the reaction, allows measurement of total BR, so minus the conjugated value to get unconjugated value
Is the hyperbilirubinaemia conjugated or unconjugated in paediatric jaundice? Why?
Unconjugated in normal paediatric jaundice as caused by liver immaturity- cannot conjugate the BR fast enough.
What does phototherapy convert bilirubin to? Why is this helpful to treat paediatric jaundice?
Lumirubin and photo-bilirubin. These isomers do not need to be conjugated to be excreted.
What is the inheritance pattern of Gilbert’s syndrome?
Autosomal recessive
What do you see in LFTs in Gilbert’s?
Raised unconjugated bilirubin with otherwise normal LFTs
What makes the bilirubin levels worse in Gilbert’s?
Fasting
Pathophysiology of Gilbert’s
UDP glucuronyl transferase activity is reduced to 30%
What is the most representative marker of liver function?
Prothrombin time (if raised, shows liver isn’t making clotting factors so isn’t working properly)
(Albumin and BR also good)
Why are the enzyme LFTs (AST, ALT) not true markers of the liver’s synthetic function?
They tell you that there is damage rather than telling you how your liver is actually functioning
What do high AST and ALT indicate?
Hepatocyte damage e.g. hepatitis
In what type of hepatitis is AST > ALT?
Alcoholic hepatitis