Hepatitis Flashcards
Define hepatitis
Inflammation of the liver
Define Hepatitis virus
Replication specifically in heptaocytes
Destruction of hepatocytes
What are the two most common viral Hepatitis?
Hep B and C with approx 240 million people worldwide are infected with hep B
What type of virus is hep B ?
Double stranded enveloped DNA virus.
What is the mechanism of transmission of hepB ?
Via blood , sexual intercourse and vertical transmission
Once an individual has been infected with HBV , how many weeks / months does it take to incubate and cause damage to persons liver ?
Can take 6 weeks -6months for the virus to incubate and begin to cause damage to the persons liver
What percentage of people with HBV will have vague symptoms/ asymptomatic ?
50%
Of those who do have symptoms with Hep B , what symptoms do they experience ?
Jaundice
Nausea
Fever
Vomiting
Arthralgia ( joint pain )
What are possible outcomes for those who have acute Hep B ?
50% of adults will clear the infection themselves within around 6 months.
Of the remaining symptomatic 50% , 10% will progress from an acute to a chronic infection which 25% would develop liver cirrhosis and 5% develop hepatocellular
What is the most important test for hep B ?
Serology - this is analysis of blood serum. The serology of Hep B involved three antigens and three antibodies
What are the three antigens and three antibodies that serology of Hep B detects ?
- HBsAg which is the Hep B surface antigen, this is an indication of an infection present.
- Second antigen is HBeAg : this can be detected in the blood and indicates that there is active viral replication which means that the patient is infectious and virus can spread to other people.
- The third antigen is HBcAg: the c stands for core.
- Matching antibody for HBsAg is HBsAB.
- Matching antibody for HBeAG is HBeAb.
- The matching antibody for HBcAg is IgM unless the patient has had a previous encounter to the infection before in which it will then be IgG.
In what order would the antigens and antibodies appear in someone with Hep b ( acute , for the first time ) ?
- Contract the virus through unprotected sex
- After 6 weeks , the HBsAg is detectable in blood serum. There is a corresponding rise in ALT on liver function tests.
- Symptoms start to appear at this point
- HBeAg appears and the patient is now infectious.
- HBcAG is present in the blood but not detectable by serology.
- HBcAB appears in the form of IgM.
- HBeAB appears and after HBeAG has been cleared , the person is no longer infectious.
- HBsAB appears and the virus is completely cleared from the body.
IGM is then converted to IGG and persists in the body.
What would be detected in the blood of Hep Bwas to become chronic ?
HBsAg would stay in the body for longer than 6 months.
Can chronic Hep B. Be treated ?
No , those infected will spend the rest of their life taking anti virals to try and suppress viral replication.
What preventative measure can be carried out to prevent Hep B ?
There is a vaccine for HBV.
It involves injecting the patient with a genetically engineered surface antigen for HBV ( HBsAg) that is harmless and aLows the body to develop HBsAB so it can fight off the HBV infection.
The target for long term protection is if the patient has more than 100 surface antibodies. There are three does and any boosters which is effective for most people.
The WHO recommends that all babies are vaccinated preferably within 24 hours of birth.
What type of virus is Hep C ?
Single stranded RNA virus that is enveloped and icosahedral in shape.
Mechanism of transmission of Hep C
Blood and sex ( transmission through sex is very low)
Which part of the population are most at risk of developing a Hep C ?
Those that come into contact with need,Ed including IV drug users and healthcare workers who face needle stick injuries.
Also those who has blood transfusions before 1991.
What is the incubation period of Hep C?
It is MUCH faster than in Hep B , it is around 6-12 weeks.
What percentage of Hep C patients do not experienc symptoms?
Around 80% of acute Hep C infections are
asymptomatic
Those who do experience symptoms in Hep C viral infections , what symptoms do they present with ?
Fatigue
Decreased appetite
Nausea
Vomiting
Abdominal pain
Dark coloured urine
Grey faeces
Jaundiced
Arthrlagia
What is the outcome of acute Hep C viral infections ?
- 15-45% of adults can clear the Hep C infection within about 6 months.
- 80% of Hep C patients will develop chronic infection (
How to test for Hep C. Viral infection ?
Serology blood test which aims to detect anti-Hepatitis C antibody.
The anti-hepatitis C antibody remains even after clearance / cure , the next step is do a viral PCR to look for Hep C viral RNA to confirm if the patient has chronic infection.
Is there a Hep C vaccine ?
No
Can Hep C be cured ?
Yes - antiviral combination can be used to r
Treat and cure HCV. The comdibintstion is 95% effective and treatment lasts around 8-12 weeks.
But it costs 20,000-60,000£
What is the incidence of contracting HIV , HEP B and HEP C ?
HIV : 1 in 300
HEP B : 1 in 3
HEP C : 1 in 30
If a healthcare worker receives a needle stick Injury from a patient with either HIV ,HEP B OR C , what precautions must be taken ?
They must wash and cover the wound.
Antivirals should be started no later than 72 hours afterwards. This treatment is called post-exposure prophylaxis which consists of three different anti virals for 28 days. Research has shown that this is not that effective for HEP C.
The hep B vaccine is very effective as post - exposure prophylaxis. If the individual tests are negative for HBsAG and positive for HBsAb then you do not need to give a booster or start the vaccination if they haven’t already .
