Chemical Pathology - Liver Disease CPC Flashcards
(53 cards)
what does the portal triad consist of?
artery
vein
bile duct
what is the space of disse?
spaces between hepatocytes and endothelium of sinusoids
blood comes into contact with liver enzymes
what causes zone 1 damage (periportal)?
directly hepatoxic substances
damage to zone 1 makes ALP rise more due to close proximity to bile duct
what causes zone 3 damage (centrilobular)?
hypoxic damage (blood lost quite a lot of O2 by time it passes through zones 1 and 2) metabolised hepatotoxic substances (zone 3 = most metabolically active cells in liver)
where does bilirubin conjugate?
as passes through liver
what are the causes of a high bilirubin?
- pre-hepatic (unconjugated) –> haemolysis
- hepatic (look at LFTs)
- post-hepatic (obstructive jaundice)
how do you measure the fractions of bilirubin?
Van den bergh reaction
- DIRECT: conjugated bilirubin
- INDIRECT: add methanol, reaction completed and allows you to measure total bilirubin
what causes paediatric jaundice?
NORMAL
caused by liver immaturity
unconjugated bilirubinaemia
how do you treat paediatric jaundice?
phototherapy
inheritance pattern of Gilbert’s
autosomal recessive
what can improve jaundice in Gilbert’s?
phenobarbital
what is the pathophysiology of Gilbert’s?
decreased UDP glucuronyl transferase activity
unconjugated bilirubin is tightly bound to albumin so does not enter urine
what does the presence of urobilinogen tell you?
enterohepatic circulation is intact
urobilinogen is always present in urine of normal people
bilirubin –> biliary tree –> into bowel –> bacteria convert it into stercobilinogen and urobilnogen
this is reabsorbed into circulation and you excrete it
what is the most representative function of liver function?
PT
what is the general rule about PT and paracetamol overdose?
if the PT is higher than the number of hours since the OD, pt should be transferred for transplant
what are the 3 ways that the function of the liver can be measured by?
- albumin
- clotting factors
- bilirubin
what does high AST and ALT suggest? what if one is higher than the other?
AST and ALT high = hepatocyte damage
ALT > AST = other forms of hepatitis
AST > ALT = alcoholic hepatitis
what are the causes of abnormal LFTs?
Pre-hepatic: Gilbert’s, haemolysis
Hepatic: viral hepatitis, alcoholic hepatitis, cirrhosis
Post-hepatic: gallstones, pancreatic
causes of pre-hepatic jaundice
haemolysis
CHF
causes of hepatic jaundice
liver failure gilbert syndrome crigler-naijar syndrome viral hepatitis alcoholic hepatitis PBC
causes of post-hepatic jaundice
obstruction of biliary tree
- intraluminal: stones, strictures
- luminal: mass, neoplasm, inflammation (PSC/PBC)
- extra-luminal: pancreatic Ca, cholangiocarcinoma
what are the features of hepatitis?
- fever
- jaundice
- raised ALT/AST
how is Hep A transmitted?
- faeco-oral (food, men-on-men sex)
- contaminated water, recent shellfish
how does Hep A present? time period?
acute: asymptomatic OR nausea, D+V, fever, jaundice, RUQ pain
onset: 2-6 weeks, symptoms last 8 wees
infectious when asymptomatic
