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15 Cards in this Set
- Front
- Back
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What is unique about the size of the HBV genome?
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HBV has a small(3.2kb) genome that has 4 overlapping genes: S codes hepatitis B surface antigen (HBsAg) C encodes hepatitis B envelope antigen(HBeAg) and hepatitis B core antigen(HBcAg), P codes for DNA polymerase: and X encodes HBxAg).
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How common is HBV infection? How is it transmitted?
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> 350 million are HBV carriers worldwide and about 1.2 million HBV carriers in the US> Vertical(maternal-infant) transmission in endemic areas(southwest Asia, China, and sub saharan Africa).
Horizontal(transfusions, sexually,, IV drug) transmission in areas of low prevalence. |
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Does HBV cause acute or chronic hepatitis?
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Both. 90% of perinatally acquired HBV develop chronic HBV infection whereas less than 5% of immunocompetent adults develop chronic HBV after infection.
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How can HBV infection be diagnosed?
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Most commonly serologically using HBsAg, but diagnosis can also be obtained using immunohistochemistry, in situ hybridization, or PCR
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What are the commonly used serological markers for HBV?
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HBsAg, HBeAg, anti-HBc IgM, antiHBcIgG, anti-HBs, anti HBe(HBeAb), and HBV DNA
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What is the significanceof HBsAg?
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Presence of HBsAg in serum is diagnostic for HBV infection. HBsAg typically appears in the blood 1-10 weeks after infection. Persistence of HBsAg for over 6 months is diagnostic for chronic HBV infection.
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What is the significance of hepatitis B surface antibody(HBsAb)?
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HBsAb is protective against HBV infection and detectable HBsAb correlates to resolution of an acuteHBV infection, past HBV infection, or successful immunization.
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What is the significance of anti-HBc?
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Anti-HBc IgM develops before HBsAb and is usually diagnostic for acute HBV infection. Anti HBcIgM is detectable during the window period. Anti-HBc IgG is indicative of past acute or chronic HBV infection.
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What is the window period?
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In acute HBV infection, there may be a window period following the disappearance of HBsAg in the serum but before the appearance of HBsAb. During this period, anti-HBcIgM is usually detectable. However as the laboratory sensitivities for detection of HBsAg and HBsAb have improved, this window period is now rarely clinically significant.
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What is the significance of HBeAg?
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HBeAg is a marker of HBV replication and infectivity. Anti-HBe may be detected in both patients with acute or chronic HBV infection.
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What are clinical serological markers for hepatitis?
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AST/ALT
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What is fulminant hepatitis?
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Unusual(0.1-0.5%) outcome folowed by HBV infection that results from massive immune-mediated lysis of infected hepatocytes. More than 50% of all fulminant hepatitis cases are related to HBV but usually with underlying Hepatitis D virus(HDV) or hepatitis C(HCV).
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What cancer is associated with HBV infection?
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Hepatic carcinoma
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What is the treatment for HBV infection?
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Adult acquired acute HBV usually do not require treatment. Neonates born to HBsAg positivemothers should receive HBV vaccine and HBsAb immediately following birth. Chronic HBV patients may be treated with alpha interferon or lamivudine(RT inhibitor)
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Who should get the HBV vaccine?
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Everybody should be vaccinated as it has been shown to be safe and cost effective.
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