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Sunday, October 20, 2013

Hepatitis B

HBV(DNA) from Hepadna virus
Incubation Peroid:
6 weeks-6 months
Mode Of Transmission:
Parenteral, sexual, vertical
Clinical Course:
Prolonged and more severe than A

Laboratory Diagnosis:
-Elevated ALT,AST from 10-100 folds Acute infection with resolution
-Viralantigens:
1) Surface antigen (HBsAg) is secreted in excess into the blood as 22 nm spheres and tubules. Its presence in serum indicates that virus replication is occurring in the liver
2) 'e' antigen (HBeAg) secreted protein is shed in small amounts into the blood. Its presence in serum indicates that a high level of viral replication is occurring in the liver
3) core antigen (HBcAg) core protein is not found in blood
-Antibody response:
1) Surface antibody (anti-HBs) becomes detectable late in convalescence, and indicates immunity following infection. It remains detectable for life and is not found in chronic carriers (see below).
2) e antibody (anti-HBe) becomes detectable as viral replication falls. It indicates low infectivity in a carrier.
3) Core IgM rises early in infection and indicates recent infection
4) Core IgG rises soon after IgM, and remains present for life in both chronic carriers as well as those who clear the infection. Its presence indicates exposure to HBV.



Figure: Acute Hepatitis B Infection

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