Liver Failure Flashcards
(18 cards)
What is jaundice?
Yellow skin or sclera
- normal bilirubin —> 17µmol/L
- >30 —> yellow sclera
- >34 —> yellow skin
What are the 3 categories of causes of jaundice?
- Pre-hepatic —> excess production
- too much for liver to conjugate - Intrahepatic —> issue in hepatic cells
- liver can’t conjugate - Post-hepatic —> obstructive jaundice
- can’t be released
What are the 4 pre-hepatic causes of jaundice?
Lots of erythrocytes die —> too much bilirubin produced:
1. Haemolysis - haemolytic anaemia
- toxins
2. Massive blood transfusion
3. Haematoma resorption
4. Ineffective erythropoiesis
What are the 3 intrahepatic causes of jaundice?
Dec uptake, conjugation or secretion of bilirubin in liver:
1. Inherited syndromes - all auto rec
- Gilberts —> dec uptake
- inc unconjugated
- Crigler-Najar —> dec conjugation
- inc unconjugated
- Dubin-Johnson —> dec secretion
- inc unconjugated
- Rotor —> dec secretion
- inc unconjugated
2. Cholestasis —> dec secretion
- sepsis
- TPN (Total Parenteral Nutrition)
- drugs
3. Liver failure
What are post-hepatic causes of jaundice?
- Stone
- Tumour
What is liver failure?
Rate of hepatocyte death > regeneration
- death via apoptosis or necrosis
- consequences —> coma
—> multi-organ failure
—> death
- acute - fulminant = severe in < 8weeks
- sub-fulminant = severe in < 6months
- severe —> impaired synthetic function
(INR, PT, albumin)
—> encephalopathy (impaired brain)
- chronic = cirrhosis
What are the 6 causes of acute liver failure?
- Toxins —> usually in west
- Inflammation —> usually in east (hep B, E)
- Pregnancy disease
- Drug reactions - single agent or combinations
- Vascular diseases
- Metabolic causes - eg. Wilson’s (Cu deposits), Reye’s
What are the 7 causes of chronic liver failure?
- Inflammation - eg. persistant hep
- Alcohol abuse
- Side effects of drugs
- Cardiovascular —> dec venous return (right)
- Inherited disease - eg. haemochromatosis
- NASH (non-alcoholic steatohepatitis)
- Autoimmune hepatitis , PBC, PSC
What is cirrhosis?
Chronic liver failure
1. Noxious factor —> hepatocyte necrosis
2. Cell contents leak —> activate Kupffer cells
—> inflammatory cells recruited
3. Lots of growth factors and cytokines released
- fibrosis - inc ECM production —> inc chemotaxis
- fibroblast proliferation
- cholestasis
- portal hypertension
- metabolic failure
What are the 3 main functions of hepatocyte?
- Metabolic/catabolic —> carbs, lipids, proteins
- Secretory/excretory —> proteins, bile, waste
- Detoxification/immunological —> pathogens, drugs
What are the 6 consequences of liver failure?
- Ascites (fluid in abdomen)
- dec protein synthesis (albumin)
—> dec plasma volume —> 2° hyperaldosteronism
—> hypokalaemia
—> alkalosis
- dec protein synthesis (albumin)
- Coagulopathy and bleeding
- dec clotting factor production (not vwf, VIIIC)
- Cholestasis
- bile blocked from leaving
- Portal hypertension
+ Encephalopathy and cerebral oedma
∵ dec detoxification
+ Hypoglycaemia
∵ dec glycogen storage
+ Susceptible to infections
∵ dec immunity and globulin production
+ Circulatory collapse and renal failure
∵ dec homeostasis balance
What is cholestasis?
Bile blocked from leaving liver
Effects:
- canalicular dilation
- dec cell membrane fluidity
- deformed brush barrier
- biliary transporter issues
- inc tight junctiin permeability
- dec mitochondrial ATP synthesis
Consequences:
- jaundice (inc bilirubin)
- pruritus (endorphins and bile salts in blood)
- cholesterol deposition
- fat soluble vitamin deficiencies - K —> bleeding
What is portal hypertension?
High blood pressure in portal venous system
Causes:
- pre-hepatic —> PV thrombosis
- intrahepatic - presinusoidal —> chronic hep, PBC,
granuloma
- sinusoidal —> acute hep, alcohol, fatty
liver, toxins
- postsinusoidal —> venous occlusive
disease, Budd-Chiari
- post-hepatic —> right heart failure
—> constrictive pericarditis
Consequences:
- malabsorption
- splenomegaly
- vasodilation
- encephalopathy
- varices
- severe bleeds
What is hepatic encephalopathy?
Damage to brain due to hepatic malfunction
due to:
- hyperammonaemia
- hypokalaemia
- toxins
- false transmitters
Where to varices due to liver failure occur? (4)
- Azygous vein tributaries
- Paraumbilical veins
- Superficial veins of anterior abdominal wall
- Renal veins
How is the severity of liver failure assessed?
Child-Pugh Score
- parameters - 1-3 points
—> total bilirubin
—> serum albumin
—> INR
—> ascites
—> hepatic encephalopathy
- sum of points —> class
- 5-6 = class A —> life expectancy 15-20 years
—> 10% POM
- 7-9 = class B —> transplant
—> 30% POM
- 10-15 = class C —> life expectancy 1-3 months
—> 82% POM
How is liver failure treated?
Supportive treatments:
- encephalopathy —> dec protein intake
—> don’t sedate
—> phosphate enemas/lactulose
- hypoglycaemia —> dextrose infusion - 10-50%
- hypocalcaemia —> calcium gluconate - 10ml 10%
- renal failure —> haemofiltration
- respiratory failure —> ventilation
- hypotension —> albumin
—> vasoconstrictors
- infections —> antibiotics
—> do frequent cultures
- bleeding —> vit K
—> FFP
—> platelets
Liver Support Devices:
- artificial —> albumin exchange system (removes
albumin-bound toxins)
- bioartificial —> grow hepatocytes in culture
- hepatocyte transplantation
Full liver transplant
How does liver failure cause death? (7)
- Infections - bacterial, fungal
- Circulatory instability
- Cerebral oedema
- Renal failure
- Respiratory failure
- Acid-base and electrolyte disturbance
- Coagulopathy
