Hepatitis B Flashcards
Acute clinical hepatitis can occur any time between
A few weeks and 6 months after infection with hepatitis B virus
State the symptoms of acute clinical hepatitis
Anorexia, lethargy, nausea, fever, abdominal discomfort, arthralgia and urticarial skin lesions, then dark coloured urine and jaundice
State the mechanism of acute hepatitis
Immune-mediated, the greater the antigen/antibody reaction the more severe clinical and biochemical hepatitis
State the percentage of patients hospitalised with acute infection of hepatitis B and fulminant hepatitis with dissemninated intravascular coagulation and encephalopathy
1%
State the possible outcomes of acute hepatitis B virus
Recovery (90-95%) or HBsAg positive chronic infection (5-10%)
What type of virus is hepatitis B
Hepadnavirus
State the three forms of the virus seen in blood
Infectious viral particles and non-infectious spheres and tubules
What do the non-infectious spheres and tubules consist of
HBsAg
The core of the hepatitis B virus contains what
HBcAg
What is HBeAg
Split from HBcAg in the liver cell during new virus formation and released in a free soluble form in the serum
State the markers of viral replication in hepatitis B
Serum HBeAg and HBV-DNA
What is HBsAg used for
To detect both acute and chronic HBC infection
Patients positive with HBeAg are
High infectious and at risk of developing chronic liver disease and hepatoma
Describe patients who are HBsAg positive but HBeAg negative
Highly infectious with high serum HBV DNA as a result of chronic HBV infection with a virus with a mutant genome
Statte the routes of transmission of hepatitis B
Vertical (perinatal) and horizontal (sexual, parenteral, needle stick injury)
State what makes hepatitis B so infectious
May be 100million infectious particles per mL of blood, it is also stable and may survive outside of the body for weeks
State the number of people worldwide effected by HBV
350million
State the countries with the highest rates of hepatitis B infection (HBsAg 5-10%)
South-East Asia, China, Africa, Oceania and South America
State the countries with intermediate rates of hepatitis B infection (2-5%)
Eastern Europe, Mediterranean, south Ameria and the Middle East
State the countries with the lowest rates of hepatitis B infection (<2%)
Western Europe, North America and Australia
List the factors with increased risk of infection in the UK
IVDU, MSM, Immigration from areas of high endemicity, patients with learning disability who live in residential care, patients in haemodialysis units, babies born to mothers who are at risk, tattooing or body piercing with non-sterile equipment
State the number of women in areas of high endemicity who may be infection with HBeAg
10-15%
State the risk of transmission of infection from HBeAg positive blood
30%
State the risk of infection from Anti-HBe positive blood
0.1%
State how acute hepatitis B infection is usually diagnosed
HBsAg can be detected in serum, if not present, confirmed if high levels of anti HBc IgM antibodies are present
What is seroconversion
Development of significant levels of specific antibody following the infection or vaccination
Describe seroconversion in terms of hepatitis B
Anti-HBs from AntiHBc occurs some weeks after the disappearance of HBaAg
Define chronic hepatitis B infection
Persistence of HBsAg in the serum for more than 6 months
When is chronic hepatitis B more common
90% of infants, children, males and immunodeficiency
Patients with chronic hepatitis B are more at risk of
Chronic liver disease, membranous glomerulonephritis and polyarteritis nodosa
Whos more at risk of developing chronic disease
Patients who have asymptomatic or mild acute infection
State the symptoms of chronic hepatitis B
Fatigue, anorexia, depression, jaundice
What results in raised Serum AST and ALT levels
Immune system may begin to respond to the foreign viral proteins and attack the infected liver resulting in symptoms
State the percentage of individuals with chronic hepatitis B who can progress to cirrhosis or hepatoma
25%
State those who should be considered for antiviral treatement aimed at inhibition of HBV replication
Asymptomatic chronic HBV infection with raised ALT who are HBeAg positive and those with progressive liver disease
State the indications of use of antiviral therapy in the treatment of hepatitis B
Cirrhosis with evidence of ongoing viral replication in the form of circulating HBV DNA, or the presence of 2 of:
HBV DNA>2,000 IU/ml
Raised ALT
Significant liver inflammation or fibrosis
State the go to antiviral treatment for hepatitis B
A long acting preperation of pegylated alpha interferon given subcutaneously once per week for 12 months or nucelotide analogues (especially in chronic hepatiits B patients)
State the two nucelotide analogues used in the treatment of hepatitis B
Entecavir and tenofovir
When should liver transplantation be considered in hepatitis B
Advanced cirrhosis or hepatoma
State the most important means of preventing HBV infection
Immunisation, infection control procedures, screening of blood donors and transplant donors
Active hepatitis B vaccine contains what
HBsAg produced by recombinant DNA technology
State the conditions with are associated with poor responses to the vaccine
Age over 40, obesity, smoking, wrong site of injection and immunocompromised
A person with post-vaccine antiHBs level of >100
Good responder, no further antibody check, booster given in 5 years
A person with post-vaccine antiHBs level of 10-<100
Poor responder, booster now and in 5 years
A person with post-vaccine antiHBs level of <10
No response to vaccine, repeat course of vaccine and recheck antibody level, 3 months after the last dose
List the people recommended to have active vaccination against hepatitis B
direct contact with blood or body fluids, those travelling to endemic areas for prolonged stay (>1yr), renal dialysis patients, those who change sexual partners frequently (particularly MSM and both
male and female commercial sex workers), PWID, selected police and emergency services personnel, and close contacts of those with acute or chronic HBV infection.
How can passive immunisation against HBV be given
Hepatitis B specific immunoglobulin
When is a combination of passive and active immunisation used
Infants born to mothers with chronic HBV infection or who are HBsAg positive after acute infection
Healthcare workers not known to have adequate antiHBs
Previously unprotected sexual contacts and family contacts of individuals who have acute or chronic HBV infection
