viral hepatitis Flashcards
how does hepatitis cause jaundice
pre-hepatic
-haemolysis
hepatic
- failure of conjugation, transport
post-hepatic
- biliary tree
how does hepatitis cause oedema
decreased albumin production from the liver, causing a decrease in oncotic pressure. As a result, fluid leaks from vessels
how does hepatitis cause a patient to easily bruise
insufficient coagulation protein synthesis by liver
Hepatitis A virus
- nucleic acid
- route of transmission
- key notes
RNA
faecel-oral
- common in developing world
- mostly asymptomatic
- acute illness
- testing relies on ABs
Hepatitis B virus
- nucleic acid
- route of transmission
- key notes
DNA
blood
- worldwide, extremely contagious (esp vertical transmission)
- most cases asymptomatic
- acute illness
- can cause chronic e.g. cirrhosis and cancer
- long incubation (3-4 months)
Hepatitis C virus
- nucleic acid
- route of transmission
- key notes
RNA
blood
- more common in developing world, less contagious
- generally infection of adults (IV drug users, sex)
- usually doesn’t cause acute hepatitis
- curative treatment
Hep B surface antigen (HBSAg)
- as virus replicates in liver, excess HBSAg is produced and spills into blood
- HBSAg in blood is measured to confirm active Hep B
- HBSAg surface antigen used in vaccines
diagnosis of HAV
- antibody against HAV
- PCR usually not required
diagnosis of HBV
3 antigens
- surface antigen (vaccine is recombinant HBSAg)
- early antigen (surrogate for replication)
- core antigen (never found in serum)
Anti- HBS
Anti- HBE
Anti-HBC
HBV DNA PCR
diagnosis of HCV
- antibody against HCV
- HCV RNA PCR and genotype
diagnosis of chronic hepatitis
- evidence of infection >6 months
- most often diagnosed because ALT elevated
- immunotolerance
describe these blood test results
- HAV IgM +
- HAV IgG -
- HBSAg -
- HCV AB -
- IgM means current Hep A infection
IgG + would mean past infection
describe these blood test results
- HBSAg -
- Anti-HBS +
- Anti- HBC -
- HBEAg -
- no surface antigen (HBSAg -) means no current Hep B
- presence of antibodies to surface antigens (Anti-HBS +) but none to core antigens (anti-HBC-) indicates vaccination
describe these blood test results
- HBSAg +
- anti-HBS -
- anti-HBC +
- anti-HBC IgM -
- HBEAg +
- HBSAg + shows current Hep B infection
- HBEAg + means lots of viral replication
- unsure if acute of chronic
- Anti-HBC IgM - may indicate chronic (tests over 6 months needed to confirm)
treatment of acute viral hepatitis
- not required
- supportive care
- in fulminant cases - transplant
