PBL2: Liver Disease Flashcards
What is cirrhosis?
The end stage of chronic liver disease characterised by fibrosis, scarring and nodular degeneration.
What are the causes?
Hepatitis B and C Wilson's disease Alcohol haemochromatosis Autoimmune liver disease Primary biliary cirrhosis Recurrent biliary obstruction
How can hepatitis B and C cause liver disease?
Cause hepatocellular carcinoma which goes on to form cirrhosis
How is hepatitis B and C spread?
Spread through blood tranfusion/body fluids/ contaminated instruments/sexual contact/surgery/tatoos/needles
What is alcohol haemachromatosis?
High iron levels
What is Wilson’s disease?
Disorder in metabolism of copper
What is primary biliary disease?
Inflammatory disease on bile ducts so get infiltration of lymphocytes/macrophages/plasma cells cells/eosinophils
- leads to expansion of portal tract, proliferation of bile ductule, granulomas
What are the features of compensated cirrhosis?
ASYMPTOMATIC
- liver still functions
- pathological
- fibrous circles
- increased risk of decompensation and liver cancer
What are the features of decompensated cirrhosis?
LIVER CANNOT FUNCTION
- ascites, bleeding, encephalopathy
- caused by: liver cancer, infections, haemorrhage, portal vein clot
What are the main effects of liver disease on the cardiovascular system?
Portal hypertension
Low INR
Thrombocytopenia
How does liver disease reduce coagulation factors?
Cannot produce proteins Bile reduction (cholestasis) so vitamin K is malabsorped and is needed for clotting factor synthesis
What are the effects of thrombocytopenia?
Haemorrhage
Bruising
Slow clotting post injury
Why is there a low INR?
Prothrombin, clotting factors, albumin reduction as hepatocytes synthesis
What does portal hypertension result in?
Increased hydrostatic pressure in capillaries detected by the baroreceptors in the carotid arteries and so RAAS system is activated as well as the SNS to reduc preoload and release ADH
- Also porto-systemic collaterals are used so may get backflow if hypertension increases causing varices
How does liver disease affect metabolic state?
Glucose levels are low as the damaged liver cannot respond to insulin and stores cannot be broken down and released into the blood = hypolgycaemic
Ketones are high as in a starved state
Fats are the main source of energy supply
What are the complications of liver disease?
- oedema and ascites (albimun deficiency)
- Pulmonary hypertension causes vasodilation of the splanchnic circulation as all blood flow as gone to the abdomen
- hepatic encephalopathy
- bacterial peritonitis
- splenomegaly
How does portal hypertension occur?
- Kidney impairment due to ascites and cirrhosis = ADH release = hyponatremia and water retention
- hypoalbuminemia = redcued colloid pressure = water into vessels
Why are haemoglobin and platelets low?
- anaemia of chronic disease
- portal hypertension so lots of blood flow to spleen which breaks down blood cells
- GI blood loss
Why is bilirubin high?
Liver cannot conjugate bilirubin from broken RBCs so less excretion leads to jaundice
Why is urea increased?
GI bleeding = protein in blood breaks down = urea main product of this
What is AST and how is affected in liver disease?
Aspartate aminotransferase
- mitchondrial enzyme
- increases in hepatic necrosis, MI, muscle injury
What is ALT and how is it affected in liver disease?
Alanine aminotransferase
- cystolic enzyme
- specific to liver
- increased in liver disease
What does AST:ALT tell you?
If <1 there is a liver disease as ALT would be greater than AST
What is ALP and how is it affected in liver disease?
Alkaline phosphate
Found in alkaline canaliculi and sinusoidal membranes
What is Gamma GT and how is it affected in liver disease?
Gamma glutamultranspeptidase
microsomal enzyme
induced by drugs and alcohol
can determine alcohol intake if ALP normal
Why is ALP, AST, ALT and GGT high?
Hepatocyte necrosis so enzymes leak out
Not extremely high as had previous Hep C damage
What is the main treatment for liver disease?
- Thiamine (deficiency)
- Pabrinex (vitamins, cofactors, sugar energy - refeeding)
- DIeurectis (spironolactone) - for oedema
- Nutritional therapy
- Terlipressin (lowers blood pressure and relieved PH and vasoconstriction for splanchnic circulation)
- Lactulose
- banding of varices
What is Pabrinex
Refeeding Vitamins, cofactors, sugar 2 forms: 1) B1, B2 (carbs to sugar), B6 (amino acid breakdown) 2) C, B3, glucose
Why is nutritional therapy given
Carbs and proteins so not malnourished
- branched chain amino acids preventing encephalopathy, muscle wasting and increases albumin
What does lactulose do?
Reduces fluid uptake from the gut (osmotic laxative)
Acidifies gut contents so less ammonia reabsorbed = less encephalopathy
What is hepatic encephalopathy?
Neuropsychiatric abnormalities with liver disease as toxins not removed
How does hepatic encephalopathy occur?
LACTATE BUILD UP:
- ammonia exposure as liver does not clear and increased bleeding increases levels when blood is broken down
- thiamine deficiency
What is thiamine required for? How does this cause hepatic encephalopathy?
- Cofactor for pyruvate to acetyl-coA conversion so reduction = lactate build up = Wernicke-Korsakoffs
- impaired branched chain amino acid metabolism so increased aromatic amino acid uptake = distrubred neurotransmission
Why does bacterial peritonitis occur?
Build up of fluid due to ascites, intenstine gram negative bacteria
- kupffer and sinuosoidal cells usually help clear bacteria
