Approach to Liver disease

Question 1

blood supply of the liver (5)

Answer 1

• 33% of cardiac output passes through the liver
• blood supply to the liver from portal vein (80%) & the hepatic artery (20%)
• zone 1: most nourished
• zone 3: blood leaves here
• portal vein comes from the intestines, carrying blood containing ammonia etc. that needs detoxifying

Question 2

Acquired disease CS (5)

Answer 2

• weightloss
• vomiting/diarrhoea
• jaundice
• ascites
• coagulopathy

Question 3

Congenital CS (6)

Answer 3

• lethargy/depression
• head pressing
• circling
• seizures
• blindness
• ataxia

Question 4

Liver indicators

• damage
• function

Answer 4

Liver damage:

• enzymes (increase but if there is severe disease e.g. fibrosis/cirrhosis they can decrease)
• bilirubin

liver function:

• bile acids*
• ammonia
• urea/glucose/protein
• bilirubin

Question 5

ALT (6)

Answer 5

• intracellular marker
• alkaline transferase
• in the cytosol
• most liver specific
• longer t1/2 than AST
• also a marker of regeneration

Question 6

AST (5)

Answer 6

• intracellular marker
• Asparate transferase
• mitochondria and cytosol
• skeletal and cardiac muscle too
• very short t1/2

Question 7

ALKP and GGT (6)

Answer 7

• alkaline phosphatase and gamma glutamyl transferase
• take longer to increase
• shorter half lifer
• not as useful for monitoring

ALKP: liver, intestines, bones, placenta and drugs (very NON-specific)

• good markers of biliary stasis

Question 8

Bilirubin (3)

Answer 8

• stored in RBCs and released when they breakdown and die
• conjugated and excreted via bile ducts
• if it increases it is either due to decreased liver function or increase in RBC breakdown –> jaundice

Question 9

Jaundice

• types and differentiation

Answer 9

• pre hepatic (haemolysis) –> PCV
• hepatic (liver disorder resulting in intrahepatic bile duct occlusion) –> diagnosis by exclusion, consider biopsy
• post hepatic (obstruction of common bile duct/gall bladder) –>US (gall bladder enlarged? distended bile ducts?), pancreatic assessment, increase in cholesterol

Question 10

Liver function tests (2)

Answer 10

2/3 must be impaired before there is a functional problem

specificity: bile acid stimulation –> ammonia –> urea/glucose/protein

Question 11

bile acid stim test

• method
• increase relevance
• abnormality

Answer 11

• most sensitive marker of liver function
• starve for 12 hours, get blood smaple, feed high fat/AD meal, get blood sample 2 hours later

Increase with:

• congenital/acquired shunts
• diffuse hepatic failure/cirrhosis
• biliary stasis

If pre sample > post blood sample, it’s ok, GB has contracted just prior: can be set off by the smell of food

Question 12

Ammonia (4)

Answer 12

• most sensitive liver test
• must be run within 10-15 minutes of receiving, on a frozen slide
• failure of the liver to detoxify portal blood/ portosystemic shunt if increase in ammonia
• common cause of hepatic encephalopathy –> neuro signs

Question 13

Albumin

• facts (3)
• CS of decrease (3)

Answer 13

• produced by liver
• hypoalbuminaemia may also be a result of diarrhoea, PLE etc.
• decreased when <33% functioning

CS of hypoalbuminaemia:

• ascites
• decrease in clotting and wound healing (biopsies become tricky!)
• worse prognosis

Question 14

Liver biopsy (3)

Answer 14

• only ok to do if clotting times are good –> possibly give vit K just in case??
• true cut / FNA
• FNA: 23g/1 inch needle: not good for architecture but good for cell morphology
• true cut: multiple biopsies required, GA needed