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
What are the characteristic features of Hep B?
It has a relatively long incubation period
It causes liver damage by antiviral immune reaction
Chronic infection is established when the immune system fails to eradicate the virus
What happens in Chronic Hep B infection?
There is a production of excess HBsAg by hepatocytes.
The suppressed virus may mutate and and develop altered antigens resulting in flares of inflammation.
Over time, there is progressive scarring, cirrhosis and risk of hepatocellular carcinoma.
What is the pattern of Hep B infection if a child is infected at birth?
There is tolerance to the viral antigens
Hep B can proliferate in hepatocytes to release high levels of viral particles into the blood without any liver injury.
Eventually, a limited immune reaction develops, resulting in chronic hepatitis.
What is the management for acute viral hepatitis?
No antivirals given
Monitor for encephalopathy
Monitor for resolution
of Hep B or Hep C, or Hep E if immunocompromised
Notify Public Health
Immunisation of contacts
Test for other infections if at risk
Vaccinate against other infections if at risk
What is the management for chronic viral hepatitis?
increasing number, four for HCV, six for HBV in current BNF
Two of the HCV antivirals are very new
other hepatitis viruses
if cirrhotic: influenza, pneumococcal
Hepatocellular carcinoma awareness/screening
most important for patients with cirrhosis
serum -alpha fetoprotein (AFP) and ultrasonography
Who should be treated for chronic viral hepatitis?
HCV RNA present
HBsAg and Hep B DNA present
Risk of complications:
biopsy evidence of inflammation / fibrosis often sought
non-invasive tests of fibrosis e.g. fibroscan good at identifying cirrhosis
biochemical evidence of inflammation (↑ALT)
Fit for treatment:
established cirrhosis more difficult to treat
liver cancer already is a contraindication
HIV co-infection more difficult to treat
not at increased risk of serious side effects of antivirals
attitude to treatment, and lifestyle issues
What is interferon alpha?
Part of immune response to viral infection
Made by drug companies by genetic engineering
Given by injection as pegylated interferon (peginterferon)
Complex mode of action, including as immune-adjuvant
Many side effects
What are the two treatment options for chronic hep B?
Suppressive anti-viral drug
What are the aims/benefits of Chronic Hep B therapy?
reduction in HBV DNA (suppression)
loss of HBeAg (more enduring suppression)
loss of HBsAg (cure)
Improved liver biochemistry
Reduced progression to cirrhosis and primary hepatocellular carcinoma
What are the aims/benefits of chronic Hep C therapy?
Response defined by loss of HCV RNA in blood sustained to 6 months after end of therapy
known as Sustained Virological Response or SVR
relapse after SVR is rare
reinfection can occur
After SVR patients have:
improved liver biochemistry
reduced incidence of primary liver cancer
What is the therapy for chronic viral Hep C?
Peginterferon injections given in combination with ribavirin tablets (PR)
this was the standard of care for some years
Given for 12 to 48 week courses
duration depends on response and HCV genotype of infection and what other antivirals given
Protease Inhibitors (PI), protease is product of viral gene NS3
proven in genotype 1 infection to increase responses when given as triple therapy (PR+PI)