Hepatitis B Flashcards
1
Q
What is the burden of Hep B in Australia?
A
- 1 in 3 in with Chronic Hepatitis B(CHB) in australia remain undiagnosed
- 1 in 4 with CHB without appropriate monitoring or treatment will die of liver cancer or liver failure
- 200,000 in Australia are living with Hep B
- It can survive outside the body for upto 7 days; 50-100 times more infectious than HIV
2
Q
How is Hep B transmitted?
A
- Transmitted through infected blood or bodily fluid (semen,vaginal fluids)
- Vertical transmission from mother to child during childbirth is the most common mode in high prevalence countries
- Horizontally from an infected individual to an unvaccinated household contact by sharing toothbrush, razors or other personal items
- Sexually through umprotected vaginal, anal or oral sex
- Percutaneously through sharing or re-using injecting equipments including tattoo/body piercing
- Medically acquired in some countries where blood transfusions and organ transplants pose a high risk
- Salivary transmission is very rare; urine, faeces, sweat, tears and breast milk is negligible risk
3
Q
Who are the priority populations to screen?
A
- People born overseas with intermediate or high risk HBV prevalence (Asia-Pacific region)
- Aboriginal and Torres Strait Islander people
4
Q
Who to opportunistically test for Hep B?
A
- People born in intermediate and high risk countries
- Aboriginal and Torres Islander people
- Pregnancy
- Sexual, household contacts and family members with Hep B
- Men who have sex with men
- People who inject drugs
- People with multiple sexual partnes
- Haemodialysis patients
- People with Hep C/HIV
- Patient about to commence chemotherapy or immunosuppressive therapy
- Health professionals, armed forces
- People with elevated ALT/AFP
5
Q
How to test for Hep B?
A
- Informed consent including agreeable to be tested, understanding the procedure and reason for testing and able to assess personal implications of a positive test result
- To retain medical eligibility, write chronic Hep B and can order HBsAg, anti-HBs and anti-HBc simultaneously
- If acute hep B suspected, IgM anti-HBc antibodies are elevated. Also elevated to a lesser degree in flare up of chronic Hep B infection
6
Q
How to interpret Hep B test results?
A
7
Q
Who should be vaccinated for Hep B?
A
- NIP has infants and catch up in adolescents
- People at higher risk, people prone to exposure and people at risk of occupational exposure
- People from high risk groups need to be tested before vaccination
- Close contacts of people with Hep B, peole at significant risk of occupational exposure, immunodeficiency and at risk of severe disease need to be tested after vaccination
- Non responders should be offered further doses (recheck 4 weeks post vaccine).
- Persistent non responders should be informed they are not protected and should minimise exposure. Hep B immunoglobulin within 72 hrs of parenteal exposure to Hep B
8
Q
How to manage patients with acute Hep B?
A
- Generally no treatment as most will naturally clear
- 5% will go on to have chronic hep B
- Symptoms of fever, jaundice, anorexia, nausea and RUQ pain.Elevated ALT is noted
- HBsAg clears within a few months and coincides with development of anti-HBs
- If HBsAg persists for more than 6 months, indicates progress to CHB
9
Q
What is the natural history of chronic hep B infection?
A
- People with chronic Hep B do not exhibit symptomsuntil they have developed cirrhosis or cancer
- The risk of infection is >90% in infants <5 years and <5% in adults
- CHB is defined as persistent detection of HBsAg for > 6months after intial viral exposure
10
Q
How to monitor chronic Hep B?
A
11
Q
What is the initial assessment of patients with Hep B?
A
- Risk factors for acquisition of CHB, such as ethnic background, a family history of CHB, and hepatocellular carcinoma; and host or viral factors that are associated with an increased risk of cirrhosis, including older age (related to a longer duration of infection), heavy alcohol consumption, cigarette smoking and co-infection with other viruses, e.g. (HCV),
(HDV), and (HIV).
12
Q
How do you monitor patients with CHB?
A
13
Q
What is the surveillance guideline for Hepatocellular carcinoma
A
14
Q
Who and when to treat in CHB?
A
- Patients in the immune clearance and immune escape phases of infection are candidates for therapy. Treatment is considered for patients with high HBV DNA.
Other factors important in the decision to begin antiviral therapy are:
■ Patient’s age
■ Degree of inflammation
■ Fibrosis stage
■ Risk of HCC
- A liver biopsy is no longer a compulsory requirement for the reimbursement of therapy for HBV.
- Ultrasound elastography, known as FibroScan®, provides non-invasive estimation of fibrosis and reduce the need for biopsy.
15
Q
What are the current recommended first line therapies?
A
- Entecavir has excellent tolerability, high potency and a high barrier to resitance
- Tenofovir has high resitance to lamivudine resistance HBV and Rx of choice in pregnancy
- Pegylated interferon is less likely to be prescribed due to side effects.Uesful in younger patients
