Hepatitis B and D

Question 1

Which types of hepatitis are only acute forms?

Answer 1

A and E - usually caught from water

D - pretty uncommon as its only with Hep B

Question 2

Which types of hepatitis are chronic infections?

Answer 2

B and C- can also be carriers for it

Question 3

Where is hep b most prevalent and how is it transmitted?

Answer 3

china, sub-saharan africa, indian subcontinent = endemic

vertical transmission and horizontal in childhood (passed through generations)

Question 4

What is sporadic hep b?

Answer 4

acute hepatitis B
- low incidence in UK
transmission is via sex or IV drug use - majority of drug users in UK have been vaccinated against it

Question 5

What are the current populations in the UK screened for hep B?

Answer 5

blood and organ donors
healthcare workers
pregnant women 
dialysis patients 
GUM clinic attendees
IVDU/prisoner

Question 6

What are the key components of a virus and how does viral replication occur?

Answer 6

envelope protein - HBV surface antigen
nucleocaspid- HBV core antigen
nucleic acid - HBV DNA
HBV polymerase

1) DNA replication - viral and host enzymes
2) Manufacturing the viral proteins - host machinery

Question 7

How do viruses convert RNA to DNA?

Answer 7

Using their own reverse transcriptase

Question 8

How does the liver damage actually occur in hepatitis?

Answer 8

infection and replication cause no damage
liver damage is immune-mediated => lymphocytes kill infected cells
so lymphocytes must recognise infected cells first
HLA molecules display intracellular proteins at the cell surface = both human and foreign

Question 9

How does risk of chronic infection vary at different ages and what are the risks of carriage?

Answer 9

Neonate = vertically transmitted = nearly 100% risk of carriage 
Toddler = horizontal (close contact) = 50% risk of carriage 
Adult = sexual (mainly) = <5% risk of carriage

Question 10

What is the natural history of HBV from vertical infection?

Answer 10

infection

• > 95% chronic hepatitis => HbsAg positive and anti-Hb negative, antiHBc positive=> either become healthy carrier or cirrhosis which can lead to liver failure or liver cancer
• <5% resolution and immunity => HbsAg negative, anti-hb positive and antiHBc positive

Question 11

What are the older and newer drugs for hep b treatment?

Answer 11

interferons = interferon (old) and pegylated IFN-alpha 2a (newer) - interferons are much less commonly used nowadays

nucleoside analogues (reverse transcriptase inhibitors)= lamivudine, adefovir and telbivudine (old) and entecavir and tenofovir (newer) 
by blocking reverse transcriptase you prevent viral particles being manufactured

Question 12

What is the aim of the treatments for HBV?

Answer 12

reduction of serum viral titre
reduction of liver inflammation and normalisation of LFTs
prevention and regression of liver fibrosis => prevention of liver failure and reduced risk of liver cancer

Question 13

What are the key facts about hep D?

Answer 13

HDV infection requires HBV co-infection - simultaneous acquisition or superinfection of chronic HBV
HDV infects up to 10% of HBV patients in UK - coinfected pts are migrants from areas of high risk
HDV suppresses HBV- HDV is responsible for the liver damage, suppresion of HBV with nucleoside does not affect severity of HDV hepatitis or rapid fibrosis progression
some cases of HDV respond well to interferon