Flashcards in Viral hepatitis Deck (41)
What are the hepatitis viruses?
Hep A, B, C , D, E
How is Hepatitis A spread?
Some cases imported
gay men and Injecting Drug Users
What are the clinical features of Hep A?
Acute hepatitis, no chronic infection
Peak incidence of symptomatic disease in older children / young adults
Relatively short incubation period
Mild illness, full recovery usual
How is acute infection of Hep A confirmed?
Clotted blood for serology (gold top vacutainer)
same sample for all causes of viral hepatitis
Hepatitis A IgM (usually detectable by onset of illness)
How is Hep A controlled?
Where is Hep E found?
More common in tropics
Has become more common than Hep A in UK
What are the clinical features of Hep E?
Acute hepatitis, but immunocompromised humans can become chronically infected
How is Hep E transmitted?
There is evidence of chronic Hep E infection in which animals?
What are the Hep E cases in the UK thought to be?
Is there a vaccine available for Hep E?
When is Hep D found?
Only found with Hep B
It exacerbates the Hep B infection
How is Hep B transmitted?
Mother to child (from blood during delivery)
When is chronic Hep B infection more likely to result?
Chronic infection more likely to result if first exposure is in childhood
What people in the UK are at higher than average risk of contracting Hep B?
Multiple sexual partners
Injecting drug users
Children of infected mothers
How is Hep B confirmed in the lab?
Hepatitis B surface antigen (HBsAg) present in blood of all infectious individuals
the surface antigen is present for more than 6 months in chronic infection
Hepatitis B e antigen (HBeAg) usually also present in highly infectious individuals
Hep B virus DNA always also present in high titre (amount) in highly infectious individuals
Hep B DNA tests also used to predict risk of chronic liver disease and monitor therapy
Hep B IgM most likely to be present in recently infected cases
Anti-HBs present in immunity
What is a more sensitive predictor of prognosis and infectivity: Hep B DNA or HBeAg?
Hep B DNA
What measures reduce the risk of contracting Hep B?
Minimise exposure: safe blood, safe sex, needle exchange, prevention of needlesticks, screening of pregnant women
Two vaccination strategies possible
vaccination of at risk people (UK)
vaccination of all children / adolescents
plus HBIG (hyperimmune Hep B immunoglobulin)
How is Hep C transmitted?
Mother to child
What proportion of Hep C infections result in chronic infection?
Does the natural history of Hep C infection vary with age at time of infection?
No, this doesn't seem to be an important factor
How is a patient who is at risk of Hep C infection or showing signs of acute liver disease tested for Hep C?
1. The patient is tested for antibody to the Hep C virus.
If the result is negative, the person is not infected. If the result is positive, they either have been infected in the past or have a current infection.
2. For patients with a positive antibody test, test for Hep C virus DNA by PCR
If the DNA test is negative, they have had an infection in the past.
If it is positive, they are currently infected.
Is there a vaccine for Hep C?
The only control is to minimise exposure
How long does an infection have to last for to be defined as chronic?
Can chronic Hep B cure spontaneously?
Yes, this is not uncommon
Even after years of infection
Canchronic Hep C cure spontaneously?
No, once chronic infection established, spontaneous cure is not seen
What is a typical length of time from infection to cirrhosis?
> 20 years
What is a typical length of time from infection to hepatocellular carcinoma?
> 30 years
What are the only two Hepatitis viruses that can establish chronic infection?
Hep B and Hep C