Liver Failure

Question 1

Define Liver Failure.

Answer 1

Insufficient hepatocyte function to maintain homeostasis.

Inability of the liver to perform it’s normal synthetic, metabolic and excretatory function as part of normal physiology.

Question 2

State some of the functions of the liver.

Answer 2

Excretion, enzyme activation, storage, synthesis, detoxification, immune regulation

Question 3

Describe some features of the pathophysiology of liver failure.

Answer 3

Centrilobular necrosis of hepatocytes Mononuclear cell infiltration Fatty change Activation of macrophages

Question 4

What are the two main types of liver failure and how are they different?

Answer 4

Acute - occurs in a pre-existing normal liver Chronic - due to chronic liver disease

Question 5

How are the different subtypes of acute liver failure differentiated?

Answer 5

Acute - differentiated into three subtypes based on the time delay between jaundice and hepatic encephalopathy Hyperacute = < 1 weeks Acute = 1-4 weeks Subacute = 5-12 weeks

Question 6

State a fungus and a plant that can cause acute liver failure.

Answer 6

Amanita phalloides Khat NOTE: other causes include HSV, EBV, Varicella, Hepatitis A, B and E and ecstasy

Question 7

State 7 clinical features of acute liver failure.

Answer 7

1. Hepatic encephalopathy
2. Cerebral oedema
3. Coagulopathy
4. Jaundice
5. lethary
6. Nausea
7. Malaise

Question 8

What is hepatic encephalopathy and what causes it?

Answer 8

Reversible neuropsychiatric state caused by hepatocellular dysfunction and porto-systemic shunting Blood bypasses the liver and hence is not detoxified so the brain is exposed to increased levels of ammonia and other neurotransmitters

Question 9

What causes cerebral oedema? How can it cause death?

Answer 9

Caused by imbalances between carotid artery pressure and intracerebral pressure and disruption of the blood brain barrier and increased osmosis into the brain. It causes brain herniation and cerebral hypoxia.

Question 10

State some clinical features of cerebral oedema.

Answer 10

Myoclonus, dysconjugate eye movements, systolic hypertension, increased muscle tone

Question 11

What causes coagulopathy?

Answer 11

The inability of the liver to produce sufficient amounts of clotting factors. Platelet count falls and the platelets become dysfunctional. This leads to bleeding through mucus membranes, in the GIT and the brain.

Question 12

What metabolic changes take place in liver failure?

Answer 12

Plasma sodium, potassium and glucose concentration decreases. There is an increase in urinary loss. Metabolic acidosis

Question 13

Why is infection a feature of liver failure?

Answer 13

Caused by poor host defence - Kupffer cell and polymorph dysfunction and reduced conscious state (so you don’t clear their airways)

Question 14

State three rare causes of acute liver failure.

Answer 14

Budd-Chiari Syndrome Wilson’s Disease Acute Fatty Liver of Pregnancy

Question 15

What is Budd-Chiari Syndrome?

Answer 15

Caused by obstruction of the hepatic veins at any site from lobule to entry of IVC to right atrium.

Question 16

What is Wilson’s Disease? What is the treatment?

Answer 16

Due to failure of copper excretion into bile leading to copper accumulation in the liver, basal ganglia and cornea. It is treated using penicillinamine, which chelates the copper.

Question 17

What sign of Wilson’s Disease is seen in the eye?

Answer 17

Keyser-Fleischer Rings

Question 18

What are some features of chronic liver disease?

Answer 18

Jaundiced, malnourished, muscle weakness, muscle wasting

Question 19

State some causes of chronic liver disease.

Answer 19

Alcoholic liver disease, Chronic viral hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, haemochromatosis

Question 20

What scaling system is used to determine the severity of chronic liver failure?

Answer 20

Child-Pugh Scale - based on bilirubin, albumin, ascites, encephalopthy and clotting

Question 21

What is the normal pressure of the portal system and what are the complications associated with portal hypertension?

Answer 21

7 mm Hg - portal hypertension can lead to the formation of oesophageal and rectal varices, which can rupture causing severe haemorrhage. It can also cause encephalopathy, septicaemia and impaired liver regeneration

Question 22

What are the consequences of bleeding oesophageal varices?

Answer 22

Haematemesis, melaena, encephalopathy

Question 23

What apparatus can be used to tamponade bleeding oesophageal varices?

Answer 23

Sengstaken Blakemore Tube

Question 24

What is ascites? State three causes of ascites.

Answer 24

Ascites - accumulation of fluid in the peritoneal cavity causing abnormal swelling Portal hypertension Hypoalbuminaemia Sodium retention

Question 25

State some complications of ascites.

Answer 25

Spontaneous bacterial peritonitis, renal failure, encephalopathy

Question 26

What are the two types of renal failure?

Answer 26

Acute tubular necrosis - occurs in acute liver failure Hepatorenal syndrome - occurs in chronic liver failure - the kidney is fine but it doesn’t work in the context of a patient with liver failure

Question 27

What are the two approaches to artificial liver support?

Answer 27

Biological - live hepatocytes Non-biological - blood purification by absorption/dialysis type techniques

Question 28

What is auxillary liver transplant?

Answer 28

Where the donor liver is placed alongside the native liver to take over some of the function while the native liver recovers.

Question 29

How does bilirubin, plasma albumin, alanine aminotransferase (ALT) and alkaline phosphatase (ALP) change in liver disease

Answer 29

Bilirubin increases (the liver isn’t able to get rid of it quickly enough) Albumin decreases Alanine aminotransferse INCREASES (it is found in the hepatocytes so anything that destroys hepatocytes will increase ALT) Alkaline phosphatate - increases if there is an obstruction

Question 30

State three symptoms of chronic liver failure.

Answer 30

Yellowish discoloration of the eyes and skin Swelling of the body and, in particular, the stomach Vomiting up blood Rectal bleeding Gynaecomastia (in males)

Question 31

State three signs of chronic liver failure

Answer 31

Caput medusae Hepatic encephalopathy Ascites Renal failure Oedema