Clinical Biochemistry 1 Flashcards
State how the liver is perfused with blood from two supplies.
- Via the hepatic portal vein carrying blood from the intestine prior to distribution to general circulation
- Via the hepatic artery, a branch of the aorta supplying oxygen and nutrients
What are the physiological functions of the liver?
- Homeostasis
- Detoxification
- Glucose homeostasis
- Lipid homeostasis
- Protein synthesis & metabolism
- Bile acid metabolism & transport
- Hormone regulation
- Immunological function
Where is the liver located?
- The right hypochondriac and extending to the epigastrium
What are LFTs?
Liver Function Test - used as indicators for hepatic dysfunction
State the standard parameters of LFTs.
- Alkaline phosphatase (AP)
- Alanine aminotransferase (ALT)
- Aspartate aminotransferase (AST)
- Gamma-Glutamyl transferase (GGT)
- Bilirubin
- Albumin
- Total protein
What are the enzyme measurements?
1.Soluble cytoplasmic enzymes - AST & ALT
2.Membrane-associated enzymes - AP & GGT
What is Alkaline Phosphate? (AP)
Term used to describe a widely distributed set of isoenzymes
Where is hepatic AP produced?
Produced by hepatocytes, production is increased in patients with damage to the biliary system.
Which diseases is AP increased?
- Liver disease- hepatitis, cholestasis.
- Bone disease-Paget’s, bone malignancy even just via growth- teenagers.
- Pregnancy- often elevated at the end of pregnancy and beyond particularly if
the mother breastfeeds.
Where is aminotransferases widely distributed?
In liver, heart, pancreas, lung, RBCs and skeletal muscle
Where is alanine aminotransferase found?
The liver, more specific to the liver than AST
What does increased serum level indicate?
Hepatocellular damage
Where is there a high conc of gamma-glutamyl transferase? (GGT0
Liver, kidneys, pancreas, intestine and prostate
What disease is linked with GGT?
Sensitive indicator of hepatobiliary disease in
conjunction with raised AP
What is albumin levels used to measure?
Hepatic functional capacity as most albumin is manufactured in the liver.
Describe the albumin levels for Cirrhotic patients.
50% decrease in albumin levels
In which conditions is albumin also altered?
Crohns disease
Malnutrition
Malignancy
Nephrotic syndrome
What is a major function of the liver?
Manufacture plasma proteins - the main proteins are albumin and clotting factors
What is INR?
The international normalised ratio (INR) blood test tells you how long it takes for your blood to clot.
Describe the INR for patients with chronic or acute liver disease.
- Elevated INRs
How can INR be used?
Paracetamol poisoning as a marker of hepatocellular damage
What happens in those with jaundice?
- INCREASED Production of bilirubin DECREASED uptake (pre-hepatic)
- Decreased metabolism (intra-hepatic)
- Decreased excretion (hepatic + extra-hepatic)
What can unconjugated hyperbilirubinaemia cause?
- Haemolysis
- Gilberts syndrome
- Crigler-Najjar syndrome
- Drugs e.g. rifampicin
What can conjugated hyperbilirubinaemia cause?
- Intra or extra-hepatic cholestasis
- Acute Hepatitis
- Cirrhosis
What can elevated bilirubin cause?
- Jaundice
- Pale stools/dark urine
- Steatorrhoea
- Gynacomastia
- Spider naevi
- Acsites
- Oesophageal varices
- Pruritis
- Dupuytren’s contracture
