Hepatitis B

Hep B e Ag > 3 months
-> high likelihood of chronic infection

Hep B e Ag positive
-> majority have active infection
-> it also indicates greater infectivity.

Hep B core Ab
-> indicates exposure to hepatitis B virus

Hep B surface Ag > 6 months
-> indicates chronic hepatitis B infection

Hep B DNA Qualitative assay

Window period:

[ HBsAg: neg, HBsAb: neg, HBcAb: pos]

The disappearance of HBsAg (hepatitis B surface antigen) is followed by the appearance of anti-HBs. In some patients, however,

anti-HBs may not be detectable until after a window period of several weeks to months. At this time, neither HBsAg nor anti-HBs can

be detected, the serologic diagnosis may be made by the detection of IgM antibodies against hepatitis B core antigen (IgM anti-

HBc).


Rx:

Acute Hep B - fulminant infection:
- supportive
- lamivudine +- liver transplant

Chronic
-interferon
-antiviral therapy (tenofovir, lamivudine, etc)

indication for Rx in chronic infection:
-co-infection with HIV or Hep D
-cirrhosis
-if no coinection/comorbidity:
 -HBeAg positive, HBV DNA > 20 000 IU, ALT > twice upper normal limit
 -HBeAg negative, HBV dNA > 2 000 IU, ALT > upper normal limit