75% of blood entering the liver is from the hepatic portal vein and 25% from hepatic artery
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What are the functions of the liver?
Carbohydrate + lipid + protein metabolism, production of clotting factors, RBC production, metabolism of hormones + drugs, vitamin storage + metabolism, reticuloendothelial system
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General symptoms of liver dysfunction?
Tiredness and lethargy, jaundice, pale stools, dark urine, steatorrhea
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Skin signs of liver dysfunction?
Pruritis, spider-like red veins, red palms, white flecks in the nails
Markers of dysfunction rather than function and they only reflect status at the time of the test
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What are the features of the alkaline phosphatase test?
These are a group of enzymes found in the tissues which are non-specific. High concentrations are found in the biliary canaliculi, levels raised in hepatocellular damage, also found in osteoblasts and placenta.
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What are the features of the aspartate transaminase (AST) test?
Enzymes found in the heart, liver, skeletal muscles, kidneys, RBCs so very non-specific. Injury to any of these cells will cause AST to leak into circulation and levels raised. Pts with cirrhosis may show lower levels due to down regulation
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What are the features of the alanine transaminase (ALT) test?
The enzymes are found in higher concentrations in the liver than anywhere else in the body (more specific). Raised ALT indicates acute hepatitis, cirrhosis, jaundice, shock. Some drugs also increase the levels
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What is the link between liver function tests and statins?
Liver function tests should be done before starting statins, repeat at 3 months and 12 months. Stop the statin if transaminase levels are raised 3x normal
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What are the features of the gamma glutamyl transferase (GGT) test?
This enzyme is found in the endoplasmic reticulum. It is released in all types of liver dysfunction but synthesis is increased with high alcohol intake. Levels may be raised by enzyme inducing drugs, cholestasis, pancreatic disease, MI and diabetes
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What leads to jaundice?
Bilirubin is released after the breakdown of RBCs. It is normally bound to albumin but large haemolysis causes the release of lots of unconjugated bilirubin, resulting in jaundice
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How can albumin be used as a liver function test?
It is synthesised in the liver with a half life of 20 days, so it can be a marker of slow deterioration rather than acute. Hypoalbuminaemia can lead to ascites and peripheral oedema, and it affects transport of protein-bound drugs
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How can INR be used as a liver function test?
Clotting factors are sensitive to acute liver damage as they have a half-life of 2-3 days. Prothrombin time becomes abnormal when 80% of liver synthesising capacity is lost.
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Other cards in this set
Card 2
Front
What are the functions of the liver?
Back
Carbohydrate + lipid + protein metabolism, production of clotting factors, RBC production, metabolism of hormones + drugs, vitamin storage + metabolism, reticuloendothelial system
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