14- Measuring Hepatic Function Flashcards
What leak into blood when liver cells are damaged
Liver enzymes
What substances are measured in Liver function tests
Bilirubin
Alanine Aminotransferase
Aspartate Aminotransferase
Gamma-glutamyl transferase
Alkaline phosphate
Protein
Albumin
Globulins
What liver enzymes provide indication of degree of inflammation
ALT and AST
What enzymes suggest the presence of obstructive biliary disease
ALP and GGT
What is hepatitis
A term used to describe inflammation of the liver.
It can occur as the result of a viral infection or because the liver is exposed to toxic substances such as alcohol
What is chloestasis
A condition where bile cannot flow from the liver to the duodenum
What is cirrhosis
Scarring of the liver as a result of continuous long term liver damage
How is unconjugated bilirubin moved to the liver
by albumin
How is bilirubin chemicals measured to the serum sample
Diazo dyes are added to the sample and light absorbance is measured.
What ios the healthy level of bilirubin in serum
under 20micromol
What level of serum bilirubin level will cause the patient to become jaundiced
above 35micromol/L
What indicates biliary obstruction
If the conjugated bilirubin is in a higher ratio to unconjugated
What does it mean if the conjugated to unconjugated bilirubin ratio is equal
Hepatocellular damage
What is ascites
Fluid builds up in the abdomen which causes abdominal distension >1500ml of water
What are the symptoms of ascites
Discomfort
Nausea
Appetite suppression
Increasing dyspnoea
What is unconjugated bilirubin
Bound to albumin and water-insoluble so does not appear in urine
What is conjugated bilirubin
Diglucuronide, water-soluble appears in urine
What is haemolytic or pre-hepatic jaundice and what are the causes
Haemolysis of red blood cells resulting in the formation of bilirubin at a rate faster than the liver can excrete
Unconjugated>conjugated 80micromol/L
Causes- drugs, infection and enzyme deficiency
What is the causes of hepatocellular jaundice
Due to damage of hepatocytes
Causes- infection, drugs and alcohol
Intracellular enzymes leached into circulation
Damaged hepatocytes are unable to conjugate and transport bilirubin into bile.
300micromol/L conjugated and unconjugated
What is cholestasis jaundice and what are the causes
Intra-hepatic- failure of bile flow or excretion within the liver
Extra-hepatic- obstruction of biliary tree outside the liver eg gallstones or malignancy
Bilirubin up to 500micromol/L
Where is Alanine amino transferase found
Found in high concentrations in the liver and lower concentrations in the heart and muscles
What do high ALT levels indicate
Acute liver damage, chronic liver disease and jaundice
What does low ALT levels indicate
Vitamin B6 deficiency
Where is aspartate aminotransferase found
Present in liver heart kidneys skeletal muscles and RBCs
What does increased AST levels indicate
Raised in shock
Also raised in pregnancy and after exercise
Where is Gamma-glutamyl transferase found
High concentrations in the liver, kidneys, prostrate and pancreas
What is GGT levels rasied by
Alcohol consumption
What does raised GGT levels indicate
Liver and biliary tract diseases and also pancreatic cancers
Where is alkaline phosphatase found and produced
Produced in liver, bile ducts, bone and duct
Widely distributed in the body
What does increased ALP levels indicate
Raised in diseases of the liver and biliary tract wit highest levels found in obstructive jaundice
ALP is also raised in cirrhosis and liver cancers.
Only slightly raised in acute hepatitis
What does increased levels of ALP in the bone indicate
Pagets bone tumours
What happens to albumin levels in chronic liver disease
They are lowered
What does reduced albumin levels indicate
Malnutrition
chronic renal failure
nephrotic syndrome
severe burns
Over hydration
What conditions with RBCs can be indicated by increased bilirubin levels
Haemolytic anaemia
