Clinical Biochemistry 1 Flashcards
Where is the liver located?
Right hypocardium + extends into epigastrium
What is structure of the liver?
Left + right lobe
What is the left + right lobe of liver separated by?
Falciform ligament
Describe clinical biochem for the liver
Not completely specific to liver
Just says if liver dysfunction
What are the standard parameters?
Alkaline phosphate (AP) Alanine aminotransferase (ALT) Aspartate aminotransferase (AST) Gamma-glutamyl transferase (GGT) Bilirubin Albumin Total protein
What are the two enzyme measurements?
Soluble cytoplasmic enzymes (AST + ALT)
Membrane-associated enzymes (AP + GGT)
What is AP produced by?
Hepatocytes
When does AP increase?
Liver disease - hepatitis, cholestasis
Bone disease - even bone growth in teens
Pregnancy - end + breast feeding
What are the aminotransferases?
ALT + AST
Where is AST?
Liver, heart, pancreas, lungs, RBCs + skeletal muscle
Where is ALT?
Liver
= more specific
What type of enzymes are aminotransferases?
Intracellular cytoplasmic enzymes
When does AST + ALT increase?
Hepatic damage
Where is GGT?
High conc in liver, kidneys, pancreas, intestine + prostate
What is GGT an indicator of?
Hepatobiliary disease in conjunction with raised AP
What is half life of albumin?
20 days = reflect long term picture of disease
In cirrhotic patients what happens to albumin?
Decrease by 50%
Why is albumin important?
Most acidic drugs are strongly bonded to albumin
When is albumin conc altered?
Crohn’s disease, malnutrition, malignancy + nephrotic syndrome
What is major function of liver?
Manufacture of plasma proteins
What are the main plasma proteins?
Albumin + clotting factor
What is INR?
International Normalised Ratio
What is the liver responsible for?
Production of clotting factors
When are INRs abnormal?
INR > 1.2
When is INR elevated?
Chronic or acute liver disease
What can INR also be used in + why?
Paracetamol poisoning = marker of hepatocellular damage
Describe bilirubin metabolism
Unconjugate bilirubin + albumin
Unconjugated bilirubin transported with ligand
Conjugated to glucuronic acid
Conjugated bilirubin to small intestine
Bacterial proteases convert to urobilinogen
Back to blood then liver
Urobilinogen excreted in urine
What % of bilirubin is converted to urobilinogen?
10% = portal vein = hepatocyte = urobilinogen 90% = faeces
What is jaundice?
Increase production of bilirubin decrease uptake
Decrease metabolism
Decrease excretion
When is bilirubin elevated?
Unconjugated hyperbilirubinemia
Conjugated hyperbilirubinemia
What is unconjugated hyperbilirubinemia?
Haemolysis
Gilberts syndrome
What is conjugated hyperbilirubinemia?
Intra/extra-cellular cholestasis
Acute hepatitis
Cirrhosis
Jaundice
What do you need to consider?
LFT profile as a whole Other clinical factors Dynamic shifts over time Normal = doesn't mean healthy Abnormal = doesn't mean diseased
