Diseases of the hepatobiliary system Flashcards
What is the commonest sign of liver disease?
Jaudice
When is jaundice visible?
When bilirubin >40umol/l
What is pre-hepatic jaundice?
Too much bilirubin produced
- Haemolytic anaemia
What is hepatic jaundice?
Too few functioning liver cells
- Acute diffuse liver cell injury
- End stage chronic liver disease
- Inborn errors
What is post hepatic jaudice?
Bile duct obstruction
- stone, stricture, tumour – bile duct, pancreas
What kind of bile is in excess in pre-hepatic jaundice?
Unconjugated – bound to albumin, insoluble, not excreted
- patient notices yellow eyes/skin only
What kind of bile is in excess in hepatic jaundice?
Mainly conjugated,
Soluble
- patient notices yellow eyes and dark urine
What kind of bile is in excess in post-hepatic jaundice?
conjugated - soluble, excreted, but can’t get into gut
- patient notices yellow eyes, pale stool and dark urine
Which liver enzymes leak from hepatocytes?
ALT and AST
What does a mild increase of ALT/AST over a long time indicate?
Chronic liver disease
What do very high levels of ALT/AST indicate?
Severe acute liver disease.
What does Alk Phos leak from?
Bile duct
What does a high alk phos reading indicate?
Obstructive jaundice and chronic biliary disease.
What does raised conjugated bilirubin without extrahepatic duct obstruction indicate?
Disease of hepatocytes or intraheptic bile ducts.
Why might albumin be low?
Has long half life so levels may be low in chronic liver insufficiency.
How are clotting factors measured?
PT and INR
What is INR?
International normalised ratio - ratio of pt’s clotting time to normal control.
Why might PT/INR be prolonged?
Severe liver injury
Obstructive jaundice - can’t absorb fat soluble vitamins
What is the first histopathological sign of obstructive jaundice?
Bile in the liver parenchyma
- jaundice in the skin, patient is yellow
What are the other histopathological signs of obstructive jaundice?
Portal tract expansion
Oedema
Ductular reaction – proliferation of ductules around the edge
Bile salts and
- copper cant get out
- Accumulate in hepatocytes
(bile salts in skin – patient is itchy)
What is the first investigation in someone with jaundice?
USS to check for bile duct dilation.
If ducts not dilated biopsy performed.
What are most non-obstructive cases of jaundice due to?
Acute hepatitis
What is the clinical definition of hepatitis?
Liver enzymes raised, any cause
What is the histopathological defenition of hepatitis?
Inflammation seen on biopsy.
What does the clinical presentation of hepatitis depend on?
The amount of hepatocytes that are injured/killed and how well the remaining ones can regenerate.
What are the commonest causes of acute hepatitis in the UK?
Alcohol
Paracetamol toxicity
What are the other causes of acute hepatitis?
Viral
- A, B & E
Drug induced
Autoimmune
Seronegative (i.e. idiopathic)
What are the histopathological features of mild acute hepatitis?
Lobular disarray
Inflammatory cells
Hepatocytes vary in cells
Spotty necrosis
What are the histopathological features of severe acute hepatitis?
Confluent panacinar necrosis
What is bridging necrosis and where is it seen?
Confluent necrosis of adjacent hepatocytes in a ‘bridge’ between a portal tract and hepatic vein.
Seen in acute hepatitis of intermediate severity
What are the causes of chronic hepatitis?
Immunological injury - virus
- autoimmune
- drugs
Toxic/metabolic injury
- fatty liver disease
- alcohol, non-alcoholic fatty liver disease (NAFLD)
- drugs
Genetic inborn errors
- iron
- copper
- alpha1antitrypsin
Biliary disease
- autoimmune
- duct obstruction
- drugs,
Vascular disease
- clotting disorders
- drugs
What is the pathology of chronic liver disease?
Injury to liver cells, inflammation, formation of scar tissue and regeneration of hepatocytes
- Non-specific features of injury
Specific pathological features depend on the cause of injury
How are biopsies used in liver diease?
To determine the cause of the damage
- specific features, if present
To assess the stage of disease
- how much scarring,
- spectrum from normal to cirrhosis
What are the stages of liver disease?
A normal
B portal fibrosis
C bridging fibrosis
D cirrhosis
What are the features of stage D?
and hepatocytes form nodules surrounded by fibrous tissue. Portal blood entering the liver can flow through vessels in the fibrous tissue, and not percolate through sinusoids. The cirrhotic liver therefore is inefficient in its metabolic function, even though it is or normal size or larger.
What are the characteristics of the Hep A virus?
Type - Picorna RNA
Route - Faeco-oral
Acute jaundice - common
Chronic hepatitis? - never
Chronic infection worldwide - none
Treatment - none
Prophylaxis - Vaccine Ig
What are the characteristics of the Hep B virus?
Type - Hepadna DNA
Route - parenteral
Acute jaundice - common
Chronic hepatitis? - 10% adults
Chronic infection worldwide - 350m
Treatment - IFN, lamivundine + new ones
Prophylaxis - Vaccine Ig
What are the characteristics of the Hep C virus?
Type - Flavivirus RNA
Route - parenteral
Acute jaundice - uncommon
Chronic hepatitis? - >70%
Chronic infection worldwide - 170m
Treatment - IFN, ribovarin + new ones
Prophylaxis - none
In which infection only would you see hepatitis d?
Only in people with Hep E