• Epidemiology of Hepatitis B infection
  • 2 million people have evidence of past or present infection with hepatitis B virus (HBV), and 248 million individuals are chronic carriers
  • Prevalence of chronic infection ranges from <2% in low-prevalence areas (U.S) to 2-7% in Asia
  • The rate of progression from acute to chronic HBV infection
    • 90 percent for perinatally acquired infection
    • 20 to 50 percent for infections between the age of one and five years
    • <5 percent for adult-acquired infection 
  • High risk for HCC; can develop without cirrhosis
  
  
  
  

  Posted 01/10/17 10:34:37 AM by Ying Liu

• Phases of Hepatitis B Infection
  • Acute Infection marked by appearance of HBsAg 1-10 weeks after acute exposure. Clears after 4-6 months and Surface Ab develops
  • Persistence of HBsAg for 6 months implies chronic infection. 
  • 5% of immunocompetent adult patients progress to chronic infection
  • Multiple Phases of Chronic infection exist
    • Replicative Phase: Immune Tolerance (HBeAg and HBV DNA but normal LFTs)
    • Replicative Phase: Immune Clearance (HBeAgseroconversion with increases in LFTs), characterized by flares
    • Inactive Carrier State: HBeAgneg, Anti-HBepos, and HBV DNA neg
    • HBeAgneg Chronic Hepatitis: Low levels HBV DNA, HBeAgneg
  • Reactivation can occur after clearance, particularly in the setting of immunosuppression
  • Can have co-infection with Hepatitis C and D (needs HBV Surface Ag to invade cells)
  
  

  Posted 01/10/17 10:35:45 AM by Ying Liu

• Management of Chronic Hepatitis B infection
  • Treatment is depends on presence of cirrhosis, ALT level and HBV DNA level as well as age/comorbidities as it is essentially lifelong treatment
  • Since HBV DNA integrates into host DNA, there is currently no cure
  • Options for treatment include:
    • Tenofovir (1st-line)
    • Entecavir (good for CKD)
    • Lamivudine (some resistance)
    • Pegyatedinterferon (most cost-effective)
    • Adefovir (some role in lamivudine resistant disease)
  • HCC screening is important given increased risk
  • No data for treatment of acute HepB given high rates of clearance for adults
  
  
  
  

  Posted 01/10/17 10:39:52 AM by Ying Liu

• NEJM: A comparison of Entecavir and Lamivudine for HBeAg-Positive Chronic Hepatitis B
  • 715 patients with HBeAg positive chronic HBV 
  • Randomized to 0.5mg entecavir or 100mg lamivudine once daily 
  • Histologic improvement after 48 weeks occurred in significantly more patients in entecavir group
  • Mean reduction in serum HBV DNA also greater in entevabir group (p<0.001). 
  • No difference in HBeAg seroconversion rates
  
  

  Posted 01/10/17 10:41:22 AM by Ying Liu

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