Liver failure Flashcards
What are the levels of bilirubin
What is cholestasis
What are the causes of jaudice
Pre-hepatic causes
- Haemolytic anaemia, toxins
- Massive transfusion - transfused erythrocytes short-lived
- Large haematoma resorption
- Ineffective erythropoiesis
What are the causes of jaudice (Intrahepatic causes)
Intrahepatic causes
- specific defects
- decreased BR uptake - Gilberts syndrome 5% (autosomal recessive)
- decreased conjugation BR - Crigler-Najara syndrome - brain damage in infacts - nonhemolytic syndrome
- decreased secretion of BR into biliary canaliculi - dubin-johnson syndrome (AR benign causes increase conjugation)
rotor syndrome
Intrahepatic cholestasis (decreased outflow)
- Sepsis, TPN (Total Parenteral Nutrition) and drugs
Liver failure
What is the pathophysiology of liver failure
When rate of hepatocyte death > regeneration
Combination of apoptosis or necrosis
- Apoptosis (acetaminophen = paracetamol)
- Necrosis (ischaemia)
Clinical result
Types of acute liver failure
Fulminant hepatic failure = rapid development (<8wks) of severe acute liver injury
- imapired synthetic function (INR/PT, albumin)
- encephalopathy
- previously normal lvier or well compensated liver disease
Common causes of acute liver failure
Toxins (West)
- Parac
Other causes of acute liver failure
Disease of pregnancy (acute fatty liver of pregnancy, hemolysis elevated liver enzyme and low platelets, hepatic infarction, HEV, Budd-Chiari)
- Idiosynratic drug reactions (single agent, drug combinations
- Vascular disease - ischaemic hepatitis, hepatic artery thrombosis, post arrest,
Chronic Liver failure causes
Inflammation - viral hepaptitis
Alcohol abus
Side effects of drugs - folic acid antagonist
Cardiovascular causes - decrease venous return - right heart failure
Inherited disease - glycogen storage disease, wilsons disease, galactosaemia, haemochromatosis, a1-antitrypsin defieincy
Non alcoholic steatohepatitis
Autimmune hepatitis (PBC, PSC)
How does cirrhosis happen
What are the hepatocyte functions
Metabolic and catabolic functions - synthesis and utilization of carbohydrations
Consequences of Liver Failure
Production of clotting factors - coagulopathy and bleeding
Protein synthesis - ascites
Detoxification - encephalopathy and cerebral oedema
Glycogen storage - hypoglycaemia
Immunoligcal function and globulin production - increased susceptibility to infection
Maintenance of homeostasis - circulatory collapse and renal fialrue
Why does decreased protein synthesis cause liver failure
Decreased albumin ( cannot keep fluid within vasculature) - ascites
Decrease plasma volume - hypokalaemia, alkalosis, secondary hyperaldosteronism
Decrease (cloti
What is the consequence of cholestasis
Leads to liver damage
Aggravates any bleeding tendency
- Decreased bile salts
- decreased micelles and absorption of vit K
- decreased y-carboxylation of vit K dependent colotting factors (prothrombin 2, VII, IX and X)
Causes of death due to liver
Liver support devices
Artificial (MARS, bio-logic DT) - albumin exchange system - removing albumin bound toxins from blood
Boartifical (hepactocytes in culture)
Hepatocyte transplantation (inject hepatocyte/not effective)
When do you need a liver transplant
What are some supportive treatments that you can do
Encephalopathy - reduce protein intake( decrease ammonia), phosphate enemas/lactulose (to empty bowles)
Hypoglycaemia - infusion 10-50% dextrose
Hypocalcaemia - infuse calcium gluconate
Renal failure - haemofiltration
respiratory failure - ventilation
hypotension - albumin, vasoconstrictors
infection - antibiotics
bleeding - platelets, FFP, vit K
Severity of liver failure
How you get varices
Portal-systemic anastomoses
How does cholestasis happen
Cause of portal hypertension liver failure
Decreased lympahtic flow - ascites gets worse
Thrombocytopenia due to splenomegaly
oesophageal varicies
decreased active clotting factors, thrombocytopenia and varicies, severe bleeding
exudative enteropath y(lose
Causes of protal hypertension
Increases vascular resistance
Prehepatic - PV thrombosis
Posthepatic - right heart failure, constrictive pericarditis
Intrahepatic - presinuosidal chronic hepatitis, PBC, granulomas - sinusoidal acute hepatitis, alcohol, fatty liver, toxins, posinusoidal - venous occlusive disease of venules and small veins, Budd-Chiari (obstruction of large HV - tumour or pressing)
Portal Hypertension - consequences
Increase protein vein pressure
Mall absorption
Splenomeglay (anaemia and thrombocytopaenia)
Vasodilators (glucagon, VIP, substance P, prostacyclins)
Encephalopathy - toxins from intestine (NHS) normally extracted from portal blood by hepatocytes
Varices - thin walled collateral vessels
What is encephalopathy
Apathy, memory gaps, tremor and liver coma
- Hyperammonaemia - GI bleeding and increased colonic proteins, liver can’t convert NH3 to urea
- Hypokalaemia - intracellular acidosis - activates ammonium formation - alkalosis
Tocins bypass leave - not extracted
False transmitters (e.g. serotonin) from aromatic amino acids result in increased liver failure
Transmitters - encephalopathy
