8. Hepatitis Flashcards
what is hepatitis?
inflammation of the liver
what kind of viruses cause liver damage?
- many systemic viruses cause ‘collateral’ liver damage, e.g. EBV, CMV, VZV
- hepatitis viruses
- replicate specifically in hepatocytes (hepatotropic)
- destruction of hepatocytes - replication causes fibrosis and inflammation… cirrhosis and liver cancer
How are HepB and HepC transmitted, how long incubation, and acute or chronic illness?
HepB
- blood/sex/vertical transmission
- 6wks-6mths incubation
- acute or chronic illness
HepC
- blood/sex transmission
- 6-12wks incubation
- chronic illness
What type of virus are hepB and hepC
- HepC= RNA virus
- HepB = DNA virus
what causes jaundice in hepatitis patients?
accumulation of bilirubin due to liver dysfunction
how is bilirubin produced and excreted?
- haemoglobin in aged RBCs broken down by reticuloendothelial system to produce bilirubin
- transported in bloodstream to liver via albumin
- conjugation of bilirubin in liver by UDP glucuronyl transferase to make it soluble
- a) some excreted in urine (yellow)
b) some added to bile and excreted in faeces (brown) via GI tract
where is bile produced, stored and released?
produced in liver, stored in gallbladder and released into duodenum for fat digestion
what is cholestasis?
- reduction or stoppage of bile flow
- can be intrahepatic (in liver) or extrahepatic (ducts, gallbladder or pancreas)
what are the 3 main types of jaundice? how is each caused?
- Prehepatic
- increased haemolysis - Cholestatic - intrahepatic
- viral hepatitis
- drugs
- alcoholic hepatitis
- cirrhosis
- autoimmune cholangitis
- pregnancy
- … - Cholestatic - extrahepatic
- common duct stones
- carcinoma (bile duct, head of pancreas, ampulla)
- biliary stricture
- …
which liver function tests (LFTs) are used to test for cellular integrity?
- bilirubin
- liver transaminases
- alanine transaminase (ALT) - more sensitive
- aspartate aminotransferase (AST) - alkaline phosphatase (ALP) - produced by cells of biliary tree
which LFT would indicate hepatocyte damage/decreased cellular integrity?
increased alanine transaminase (ALT) or aspartate aminotransferase (AST)
which LFT would indicate biliary tract cell damage/cholestasis?
increased alkaline phosphatase (ALP)
which LFTs are used to assess liver function?
- albumin (protein synthesised in liver so decreased in fibrosis/cirrhosis)
- coagulation tests (clotting factors synthesised in liver)
- INR (international normalised ratio)
- prothrombin time (PT)
What are the symptoms of acute hepB infection?
Up to 50% have no/vague symptoms
- jaundice
- fatigue
- abdominal pain, nausea and vomiting
- arthralgia
What are the 3 possible consequences of acute hepB infection?
- infection clearance within 6 mths - lifelong immunity
- chronic infection (<10% adult infections, 90% infancy infections)
- fulminant hepatic failure (1%)