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Viral hepatitis Flashcards

1
Q

What are the hepatitis viruses?

A

Hep A, B, C , D, E

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2
Q

How is Hepatitis A spread?

A 
Faecal-oral spread
Poor hygiene/overcrowding
Some cases imported
Some clusters
gay men and Injecting Drug Users
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3
Q

What are the clinical features of Hep A?

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

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4
Q

How is acute infection of Hep A confirmed?

A

Lab confirmation.
Clotted blood for serology (gold top vacutainer)
same sample for all causes of viral hepatitis
Hepatitis A IgM (usually detectable by onset of illness)

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5
Q

How is Hep A controlled?

A

Hygiene

Vaccine prophylaxis

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6
Q

Where is Hep E found?

A

More common in tropics

Has become more common than Hep A in UK

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7
Q

What are the clinical features of Hep E?

A

Acute hepatitis, but immunocompromised humans can become chronically infected

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8
Q

How is Hep E transmitted?

A

Faecal-oral transmission

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9
Q

There is evidence of chronic Hep E infection in which animals?

A

Pigs

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10
Q

What are the Hep E cases in the UK thought to be?

A

Zoonoses

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11
Q

Is there a vaccine available for Hep E?

A

No

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12
Q

When is Hep D found?

A

Only found with Hep B

It exacerbates the Hep B infection

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13
Q

How is Hep B transmitted?

A

Sex
Mother to child (from blood during delivery)
Blood

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14
Q

When is chronic Hep B infection more likely to result?

A

Chronic infection more likely to result if first exposure is in childhood

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15
Q

What people in the UK are at higher than average risk of contracting Hep B?

A

Ethnic minorities
Multiple sexual partners
Injecting drug users
Children of infected mothers

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16
Q

How is Hep B confirmed in the lab?

A

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

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17
Q

What is a more sensitive predictor of prognosis and infectivity: Hep B DNA or HBeAg?

A

Hep B DNA

18
Q

What measures reduce the risk of contracting Hep B?

A

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

Post-exposure prophylaxis
vaccine
plus HBIG (hyperimmune Hep B immunoglobulin)

19
Q

How is Hep C transmitted?

A

Sex
Mother to child
Blood

20
Q

What proportion of Hep C infections result in chronic infection?

A

75%

21
Q

Does the natural history of Hep C infection vary with age at time of infection?

A

No, this doesn’t seem to be an important factor

22
Q

How is a patient who is at risk of Hep C infection or showing signs of acute liver disease tested for Hep C?

A
  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.
23
Q

Is there a vaccine for Hep C?

A

No

The only control is to minimise exposure

24
Q

How long does an infection have to last for to be defined as chronic?

A

6 months

25
Q

Can chronic Hep B cure spontaneously?

A

Yes, this is not uncommon

Even after years of infection

26
Q

Canchronic Hep C cure spontaneously?

A

No, once chronic infection established, spontaneous cure is not seen

27
Q

What is a typical length of time from infection to cirrhosis?

A

> 20 years

28
Q

What is a typical length of time from infection to hepatocellular carcinoma?

A

> 30 years

29
Q

What are the only two Hepatitis viruses that can establish chronic infection?

A

Hep B and Hep C

30
Q

What are the characteristic features of Hep B?

A

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

31
Q

What happens in Chronic Hep B infection?

A

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.

32
Q

What is the pattern of Hep B infection if a child is infected at birth?

A

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.

33
Q

What is the management for acute viral hepatitis?

A 
Symptomatic
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
34
Q

What is the management for chronic viral hepatitis?

A

Antivirals
increasing number, four for HCV, six for HBV in current BNF
Two of the HCV antivirals are very new
Vaccination
other hepatitis viruses
if cirrhotic: influenza, pneumococcal
Infection control
Alcohol↓
Hepatocellular carcinoma awareness/screening
most important for patients with cirrhosis
serum -alpha fetoprotein (AFP) and ultrasonography

35
Q

Who should be treated for chronic viral hepatitis?

A

Chronic infection:
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
Patient issues:
not at increased risk of serious side effects of antivirals
attitude to treatment, and lifestyle issues

36
Q

What is interferon alpha?

A

Human protein
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

37
Q

What are the two treatment options for chronic hep B?

A

Peginterferon alone

Suppressive anti-viral drug

38
Q

What are the aims/benefits of Chronic Hep B therapy?

A 
Virological
reduction in HBV DNA (suppression)
loss of HBeAg (more enduring suppression)
loss of HBsAg (cure)
Improved liver biochemistry
Improved histopathology
Reduced infectivity
Reduced progression to cirrhosis and primary hepatocellular carcinoma
Reduced mortality
39
Q

What are the aims/benefits of chronic Hep C therapy?

A

Response defined by loss of HCV RNA in blood sustained to 6 months after end of therapy
virological cure
known as Sustained Virological Response or SVR
relapse after SVR is rare
reinfection can occur
After SVR patients have:
improved liver biochemistry
improved histopathology
reduced infectivity
reduced incidence of primary liver cancer
reduced mortality

40
Q

What is the therapy for chronic viral Hep C?

A

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)
telaprevir
boceprevir

41
Q

What are adverse effects of peginterferon?

A 
Common
flu like symptoms: chills, sore muscles, malaise etc
Less common but more severe
thyroid disease
autoimmune disease
psychiatric disease

GI (59 decks)

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