Lecture 41: Viral Heptatitis Flashcards
What sort of features of presentation can chronic hepatitis lead to?
Ascites, coagulation issues etc are features of chronic hepatitis, unusual for acute to do this.
What can lead to hepatitis?
Drugs
Viral
Bacteria
Autoimmune
Ischeamic
Describe the nature of different hepatitis virus:
HAV: Fecal-oral, Acute hepatitis (can become fulminant)
HBV: Blood, Acute, Chronic, Cirrhosis, Cancer
HCV: Blood, Acute, Chronic, Cirrhosis, Cancer
NB HAV, HBV, HCV are unrelated!!
What proportion of hepatitis virus are asympatomatic?
HAV: 30%
HBV: 20-70% (newborns dont respond to it, assured chronic infection)
HCV: 80%
Who likely get HCV?
IV drug users, (needs high viral load to infect)
Also fulminant hepatitis is rare outside of japan, unsure why.
Whats the treatments for hepatitis virus?
HAV: None *but vaccine
HBV: Suppressive (vaccine too)
HCV: Curative, no vaccine
Describe the Hep A virus:
Picornavirus
- Positive sense RNA, icosahedral caspid, non-envoloped
Describe the Hep B virus:
- Partially double stranded
- DNA virus
- Enveloped
Importantly
- HEPAtotropic DNA virus
- Utilised reverse transcriptase (Drug target), also means its oncogenic b/c it puts its DNA into host.
- HepBsAG
Whats useful with the HBSAG:
It is made int he ribosomes in large quantities and spills over into the blood (other proteins less so) therefore can be used to diagnose
Write some notes on hepatitis C:
Flavivirus
- Positive sense RNA virus
- Spherical
- Enveloped
How long does it take for Hep B to become symptomatic?
- 3 months to become symptomatic
- Does not directly damage liver cells, CD8 do this post inf.
- If CD8 response is relaxed then can be asymptomatic infection and individual can be vaccinate which helps
How is Hep ABC detected in blood?
Hep A: IgM AB
Hep B: HBSAG
Hep C: IgG AB AND viral RNA
Write some notes on detecting Hep A:
IgM AB high post acute infection after 7 weeks IgG AB becomes predominant
HAV RNA PCR usually not required
Write some more notes on detecting Hep B:
Three antigen markers:
- HBsAG
- Early Ag (surrogate for replication)
- Core Ag (never found in serum)
Three AB markers:
- anti-HBS: Cured or vaccinated
- anti-HBE: Not usually measured
- anti-HBC: Cured or acute infection
How does the Hep B antigen profile change between acute and chronic?
Acute:
- HBsAG rises and falls = highly infectious
- Anti-HBe = less infectious
- Anti-HBs rises and falls
Chronic
- HBsAG is sustained
- Total anti-HBe rises and is sustained
What must be done to detect HCV?
AB against HCV AND HCV RNA PCR + gentotype
Define chronic hepatitis:
Evidence of infection lasting more than six months
i.e HBsAG for 6+ months
i.e HCV RNA for 6 months
Most often diagnosed because ALT is elevated immunotolerance
Incorperate the slides on antibody results
now
Write some note son chronic hep B infection:
In chronic Hep B
- HBE antigen often cleared by 20-30 years age (assuming this is vaccine)(can result in a flare of active hepatitis)
- HBSag clearance is uncommon
- In adults after 5 years:
-> 20% develop cirrhosis
-> 20-25% cirrhosis will decompensate
-> 15% with cirrhosis will develop heptaocellular carcinoma which is lethal
What is the treatment of acute viral hepatitis?
- Not required
- Supportive care
- Fulminant cases = transplant
Whats the treatment of chronic hepatitis?
- To prevent cirrhosis and cancer
- To reduce transmission
- HBV = suppress, HCV = cure
What are the medications of HBV chronic hepatitis?
Those with complications or high ALT (x2 normal) then reverse transcriptase inhibitors i.e
Entecavir or tenofovir
What does HCV treatment depend on?
Virus genotype, host immunity
Previously treatment was non specific i.e ribavirin, interferon
now very specific treatments available i.e Sofosbuvir inhibitor in combination with other specific antivirals.
How can HBV be prevented?
Vaccinate at risk to prevent vertical transmission
Screen pregnant women -> Give IgG at birth and vaccinate baby (checking B response)
How is HCV prevented?
Clean needle exchange
