Today’s lecture focused on interesting clinical scenarios associated with hepatitis B virus (HBV). The first scenario involved HBV and pregnancy. Although pregnancy is generally believed to be a condition of immune-tolerance (see: fetus), flares of the virus can occur during any trimester. It is usually preferable to treat a maternal flare during the second and third trimester, if at all. If the mother is not cirrhotic, and if the viral load is not above log 5 copies, it is acceptable to follow serial LFT to see if the flare in ALT subsides, or better yet, leads to seroconversion. One clue that this may be the case is if the HBV DNA falls in accordance with the rise in ALT. Lamivudine, tenofovir and telbivudine are acceptable options.
A second consideration dealt with HBV and hepatocellular carcinoma. Risk factors for the development of HCC include genotype C (which has an endemicity in Asia), male gender, family history of HCC and older age. Who should be screened? The guidelines suggest that any cirrhotic should be screened, Africans at age 20, Asian males age 40 and Asian females at 50. That said, an individual clinician will sometimes opt to screen any HBV active carrier at any age.
Natural history, with and without treatment was another interesting discussion. First off, as an adult, contracting HBV is actually not so bad; nearly 90% will clear the virus spontaneously. For those that do not (and for anybody else), treatment should not be considered a quick cure. Consider that with the top line agents, seroconversion of the e antigen, generally considered far more likely than the holy grail of HBsAg seroconversion, only occurs in about 20% at 2 years, 35% at 4 years and just over 40% at 5 years. And, when you correctly plan to consolidate treatment for an additional 1-2 years following seroconversion, you see that treatment may last a while.
Finally, a word about HBV and vaccine resistance. Yes, you heard correctly- it is a genuine concern. Research is attempting to better understand the mechanisms and likelihood of this paradigm occuring.