Lab 9 - liver 1 Flashcards
Why do we measure Br?
evaluate different types of jaundice
What is Br derived from?
breakdown of aged RBC by the MPS
Br1 or indirect Br
unconjugated bound to albumin and formed in MPS
BrII
produced by hepatocytes
- conjugated with glucuronic acid
UBG
- absorption
bacterially reduced
- absorbed in ileum and colon and gets into circ
UBG
- where is it measured from?
urine
3 derivates absorbed in ileum
- UBG
- Vit B12
- Bile acids
where is the first place we see jaundice
mucous membrane of the genital tract
3 types of jaundice
- prehepatic (haemolysis)
- hepatic
- post hepatic (cholestasis, obstruction of bile vessels and/or bile duct)
What is bilirubin oxidised into?
- how
Biliverdin
- exposed to UV light or stored too long
Causes of increase BrI in serum
Excess production of Br I due to increased RBC destruction.
acute haemolysis
absorption of haemoglobin following massive internal haemorrhage, or after big
haematoma formation (so called ”resorption icterus”)
transfusion of stored blood, which contains many dyeing or dead RBCs
Decreased uptake of Br I from the blood by liver cells:
impaired hepatic function
(acute haemolysis)
Decreased rate of conjugation of Br I by liver cells
impaired hepatic function
Causes of increased BrII level in serum
after severe acute intravascular haemolysis (increased production).
Decreased excretion of Br II by liver cells:
Obstruction of bile canaliculi within the liver,
Obstruction of bile canaliculi due to blockage or compression of the bile duct:
Rupture of the biliary vessels or duct or gall bladder –> bile peritonitis
What does an increase in UBG mean
- haemolysis or liver cell damage
gmelin test colours
yellow - urine itself
white (opaque) – protein
purple - indicane (indol-sulphate)
green – biliverdin
brown - urobilinogen (UBG)
What does Erlich test show?
UBG
Examination of Br in faeces
Increased BrII –> Increased UBG –> increased stercobilin in faeces –> orange colour
Faeces:
Intense colour
Hyperchromic, pleichrom, hypercholic
Hypochromic, hypocholic
decreased colour due to liver failure
Hypochromic, acholic
very light colour (grey), due to bile duct obstruction
Parameters - learn off table in handout!!
Examination of hepatic excretory function
- tests?
Brom-sulphalein- (sulphobromtalein-) (BSP) retention test
Indocyane green (ICG) retention test
Examination of hepatic excretory function
- What do we examine in BSP test?
renal clearance by hepatocytes
BSP test
- colour?
purple in alkaline pH
BSP test
- what does it break down into?
thioether and brom
brom is conjugated with glucaronic acid and excreted in bile
BSP test
- elimation rate?
normally 95% gone from blood in 30-45 mins
dog and sheep - 30
cattle and eq - 40-45
BSP test
- cons
Cats not liver specific
CAn cause anaphylactic shock
BSP retention in
- dogs
- cats
- 5-10%
- 3-5%
ICG test
- pros?
more liver specific in cats
- less dangerous
ICG test: retention
- dogs
- cats
20-25%
15%
Causes of increased BSP retention (main)?
- primary liver failure
- decreased hepatic perfusion
what can cause primary liver failure?
liver cirrhosis
liver tumour
hepatic lipidosis
“lipid mobilisation syndrome”
What can cause decreased hepatic perfusion
right sided heart failure
portosystemic shunt
arteriole-venous fistulas in liver
blockage in portal vessels
congenital disease that may increase the BSP?§
decreased UDP-glucuronyl transferase activity in liver cells (congenital disorder)
name the bile acids?
Cholic acid and chenodeoxycholic acid
Bile acids:
what are they synthesised from?
cholesterol
Bile acids:
Where do they travel from and to?
excreted to bile –> stored in gallbladder –> released into duodenum
Secondary bile acids
- names
- how are they formed?
- lithocholic acid and deoxycholic acid
- deconjugated from primary bile acids by the bacteria in the intestines
Function of bile acids
detergent character
- have a key role in micelle formation and lipid digestion
- anti endotoxin effect
Bile acid conc after eatinfg?
increased
What mediates bile acid release?
cholecystokinin-pancreozymin and secretin.
When do we take a sample for bile acid analysis
1) after 12 hours starvation, 2) after eating, postprandial value - postprandial value can be 10 times (dog), 5-6 times (cat) more than the value measured after starvation.
Bile acids:
What anticoagulant do we use?
Na- EDTA or Na- citrate bc heparin diturbs the measurement
Bile acids
- normal value
Normal value (fasting): 6 µmol/l (carnivores) 20-30 µmol/l (other animals).
Causes of increased bile acids in the blood?
liver injury, hepatic cell damage - increased outflow of bile acids from the damaged hepatocytes to the blood,
bile duct obstruction or bile endothelial cell damage - decreased secretion of bile acids to
the bile, increased outflow to the plasma instead,
decrease in liver function, therefore decreased uptake of the absorbed bile acids (note: increased urobilinogen level !)
biliary stasis (cholangiohepatitis cirrhosis, hepatic or pancreatic neoplasm, pancreatitis)
portosystemic shunt (absorbed bile acids bypass liver tissue)
