Liver Failure Flashcards
Define Liver Failure.
Insufficient hepatocyte function to maintain homeostasis.
State some of the functions of the liver.
Excretion, enzyme activation, storage, synthesis, detoxification, immune regulation
Describe some features of the pathophysiology of liver failure.
Centrilobular necrosis of hepatocytes
Mononuclear cell infiltration
Fatty change
Activation of macrophages
What are the two main types of liver failure and how are they different?
Acute - occurs in a pre-existing normal liver
Chronic - due to chronic liver disease
How are the different subtypes of acute liver failure differentiated?
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
State a fungus and a plant that can cause acute liver failure.
Amanita phalloides
Khat
NOTE: other causes include HSV, EBV, Varicella, Hepatitis A, B and E and ecstasy
State five clinical features of acute liver failure.
Hepatic encephalopathy Cerebral oedema Coagulopathy Metabolic changes Infection
What is hepatic encephalopathy and what causes it?
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
What causes cerebral oedema? How can it cause death?
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.
State some clinical features of cerebral oedema.
Myoclonus, dysconjugate eye movements, systolic hypertension, increased muscle tone
What causes coagulopathy?
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.
What metabolic changes take place in liver failure?
Plasma sodium, potassium and glucose concentration decreases.
There is an increase in urinary loss.
Metabolic acidosis
Why is infection a feature of liver failure?
Caused by poor host defence - Kupffer cell and polymorph dysfunction and reduced conscious state (so you don’t clear their airways)
State three rare causes of acute liver failure.
Budd-Chiari Syndrome
Wilson’s Disease
Acute Fatty Liver of Pregnancy
What is Budd-Chiari Syndrome?
Caused by obstruction of the hepatic veins at any site from lobule to entry of IVC to right atrium.
What is Wilson’s Disease? What is the treatment?
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.
What sign of Wilson’s Disease is seen in the eye?
Keyser-Fleischer Rings
What are some features of chronic liver disease?
Jaundiced, malnourished, muscle weakness, muscle wasting
State some causes of chronic liver disease.
Alcoholic liver disease, Chronic viral hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, haemochromatosis
What scaling system is used to determine the severity of chronic liver failure?
Child-Pugh Scale - based on bilirubin, albumin, ascites, encephalopthy and clotting
What is the normal pressure of the portal system and what are the complications associated with portal hypertension?
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
What are the consequences of bleeding oesophageal varices?
Haematemesis, melaena, encephalopathy
What apparatus can be used to tamponade bleeding oesophageal varices?
Sengstaken Blakemore Tube
What is ascites? State three causes of ascites.
Ascites - accumulation of fluid in the peritoneal cavity causing abnormal swelling
Portal hypertension
Hypoalbuminaemia
Sodium retention
State some complications of ascites.
Spontaneous bacterial peritonitis, renal failure, encephalopathy
What are the two types of renal failure?
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
What are the two approaches to artificial liver support?
Biological - live hepatocytes
Non-biological - blood purification by absorption/dialysis type techniques
What is auxillary liver transplant?
Where the donor liver is placed alongside the native liver to take over some of the function while the native liver recovers.
How does bilirubin, plasma albumin, alanine aminotransferase (ALT) and alkaline phosphatase (ALP) change in liver disease
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
State three symptoms of chronic liver failure.
Yellowish discoloration of the eyes and skin
Swelling of the body and, in particular, the stomach
Vomiting up blood
Rectal bleeding
Gynaecomastia (in males)
State three signs of chronic liver failure
Caput medusae Hepatic encephalopathy Ascites Renal failure Oedema
