Liver Disease Flashcards
General functions of the liver?
Synthesis (bilirubin, cholesterol, clotting proteins, proteins)
Metabolism (drugs, proteins, carbs, bilirubin)
Immune response (Kupffer cells)
Homeostasis (glucose)
Storage (fat soluble vitamins)
Overview of liver disease
Can manifest in broad spectrum of conditions
- Ranges mild to severe
- Delayed disease occurrence and diagnosis: most of the time asymptomatic until severe loss of function (can operate at 30-40% function) “decompensated liver disease”
Brief structure of the liver
Large right lobe, smaller left lobe
Biliary ducts running through joining liver to gallbladder, small intestine, pancreas, etc.
Classifications of liver disease
Dependent on time course and pattern of disease
1) Cholestatic
2) Hepatocellular
One often leads to the other and can result in fibrosis, thus cirrhosis
What is cholestatic liver disease?
Block in the biliary flow (bile salts)
Can cause impaired absorption of fats and malabsorption
Accumulation of bile salts can lead to hepatocellular damage
1) Intrahepatic: biliary ductules blocked within liver
due to drug (paracetamol), autoimmune conditions
2) Extrahepatic: mechanical block in bile/pancreatic duct
due to gallstones, strictures in UC/CD)
What is hepatocellular disease?
Damage to the hepatocytes
Can be caused by steatosis (fatty liver disease)
- fat deposited in hepatocytes can cause cell death and cause inflammation
Causes hepatitis (inflammation)
- acute: such as paracetamol overdose
- chronic: ongoing constant inflammation
- can be small or widespread and lead to necrosis
What does hepatocyte necrosis appear as on scans?
Shrunken liver
What classifies disease as chronic?
> 6 months
Causes permanent structural changes
- progression from compensated and decompensated liver disease
What is fibrosis and cirrhosis?
Caused by toxins, drugs, disease
Fibrosis
- persistent hepatocyte damage
- leads to deposition of collagen to cause scarring of the liver tissue
- can cause disruption in blood flow
- Erratic regeneration and formation of nodules
Cirrhosis
- extensive scarring leading to reduced liver function
What is decompensated liver disease?
What is compensated liver disease?
Compensated: liver compensates for damage and is still is able to perform daily functions (until around 30% left)
Decompensated: Extensive damage affecting ability for daily functions of the liver
What is measured in the liver function tests? (6)
Bilirubin Albumin PT/INR (prothrombin time/INR) Transaminase enzymes (AST, ALP) gamma-glutamyltransferase (GGT) Alkaline phosphatase (ALP)
At least 2 must deviate from the norm to classify liver dysfunction
What is the normal range for bilirubin?
5 - 20 umol/L
Why is bilirubin measured?
Transported to liver, attached to albumin
Waste product due to RBC breakdown (performed in hepatocytes)
- conjugated and excreted via bile into intestine (found in faeces)
Increased levels indicate haemolysis/ hepatocellular damage/ cholestasis
- > 50umol/L = jaundice
What serum level is indicative of jaundice?
What are the symptoms?
Over 50umol/L (build up)
Yellowing of skin and whites of nails/eyes/palms
Pale coloured stools and dark urine
What are the normal serum levels for AST and ALT?
Why might these be raised?
AST: 0-40iu/L
ALT: 30-50iu/L
Not all patients will have raised transaminase enzymes (if functioning has reduced severely, no enzymes will be synthesised at all) but high levels will indicate inflammation
What are the normal serum levels for ALP?
Why might these be raised?
30-120iu/L
- increased levels due to cholestasis, infiltrative liver disease or damage to the biliary tree
If ALP is raised in isolation, why might this be?
Paget’s disease
What are the normal serum levels for GGT?
Why might these be raised?
30-55iu/L
Increased due to inducers (such as alcohol), cholestasis, carcinoma of pancreas and GIT
What drug can cause increased levels of GGT?
Phenytoin
What are the normal serum levels for albumin?
In liver disease, will these be raised or reduced?
35-50g/dL
Reduced
- oedema (no maintenance of oncotic pressure within cardiovascular system)
- chronic liver disease
- alcoholic patients (malnourished: reduced production)
Will the PT/INR increase/decrease due to liver disease?
Increased
- less clotting factors synthesised (risk of haemorrhage and bleeding)
What is the scoring system used to classify and assess chronic liver disease/cirrhosis?
What does it consider?
What cautions are there with using this?
Child’s Pugh Score: gives a prognosis of the disease and mortality rate (classes A, B, C)
Considers signs and symptoms, such as jaundice, encephalopathy, ascites, albumin, INR
Drug dosing is based on Child’s Pugh score, however no pharmacokinetic/pharmacodynamic data is provided (not developed to predict drug handling- cannot be used to predict the course of the drug according to liver class)
Upon diagnosis of chronic liver disease, what further investigations need to be done?
LFTs
Child’s Pugh Scoring System
Others such as:
- Ultrasounds (nodular/smooth)
- CT/MRI
- Fibroscans
- ERCP/MRCP (visualise biliary ducts)
- liver biopsy (gold standard but invasive)
- MELD (model for end stage liver disease- similar to Child’s Pugh)
What are Fibroscans?
Probe pushes air into the liver
- measures how quickly air pushes into the liver
- indicates the stiffness of the liver (advanced scarring, cirrhosis)