Liver Failure

Question 1

Is liver failure acute or chronic?

Answer 1

it can be either

Question 2

How much functional capacity must be lost before the liver fails?

Answer 2

over 80%

Question 3

What is the mortality rate in liver failure?

Answer 3

over 50%

Question 4

What causes liver failure?

Answer 4

several conditions:

• fulminant hepatitis (sudden and severe onset)
• toxic liver damage
• cirrhosis

Question 5

Liver failure does not just impact the liver - what does this condition lead to?

Answer 5

hepatic insufficiency leads to multi-organ failure

Question 6

Broadly speaking, what four components are affected by liver failure?

Answer 6

1) hematology
2) metabolism
3) hepatorenal syndrome
4) hepatic encephalopathy

Question 7

What problems with hematology does liver failure cause and why? (4)

Answer 7

1) anemia - the liver can’t provide resources like proteins to the bone marrow leading to depressed marrow function which results in thrombocytopenia, leukopenia and anemia

2) impaired hemostasis
- impaired ability to synthesize proteins like clotting factors and fibrinogen
- thrombocytopenia from depressed bone marrow function

3) impaired immune response due to leukopenia
4) disseminated intravascular coagulation (DIC), clots form in blood vessels since there is inadequate clearance of activated clotting factors

Question 8

What problems with metabolism does liver failure cause and why?

Answer 8

1) jaundice due to inadequate clearance of bilirubin
2) edema and ascites - liver failure causes hypoalbuminemia, which decreases osmotic pressure and causes a fluid shift
3) hyperammonemia (which is toxic) due to a defective urea cycle (ammonia is a byproduct of protein breakdown, the liver normally adds CO2 to make urea)
4) hyperestrogenism due to a decrease in estrogen catabolism (which in men can cause feminization and in women can cause cancer and reproductive problems)

Question 9

How does liver failure cause renal failure? (hepatorenal syndrome)

Answer 9

• portal hypertension causes these vessels to be engorged with blood
• there is also fluid loss to ascites and edema
• there is a severe decrease in renal perfusion, this causes inadequate perfusion to the kidneys and leads to ischemia
• also causes oliguria and azotemia (build up of nitrogenous products in the blood)

Question 10

What is hepatic encephalopathy? Why does it happen?

Answer 10

it is the neurological manifestations of liver failure caused when toxic compounds are not detoxified because of liver impairment and the portosystemic shunts

Question 11

What happens when ammonia builds up in the blood?

Answer 11

it reaches the brain, increases glutamate and alters neurotransmission and osmolarity, the latter of which can cause the brain to become dehyrated

Question 12

What are the manifestations of hepatic encephalopathy?

Answer 12

• hyper-reflexia
• asterixis (flapping hand tremor)

also: confusion, coma, death?

Question 13

How is liver failure treated?

Answer 13

• try to reverse the cause if possible
• treat the manifestations and complications
• use a purgative (potent laxative) to clear the gut, this will clear it of protein which would be broken down into ammonia if it gets absorbed, which can become toxic
• non absorbable antibiotics (pass through the gut only affecting gut bacteria)
• liver transplant if drugs aren’t working and the cause can’t be reversed