Acute Hepatitis B Virus (HBV) Infection

Background

• HBV is an enveloped, double-stranded DNA virus of the Hepadnaviridae family that may cause an acute self-limited infection, fulminant hepatic failure, or may develop into a chronic disease.
• Globally, approximately 240 million patients are infected with hepatitis B, with prevalence ranging from < 2% in the United States and other western countries to over 5% in some parts of East Asia, Southeast Asia, and sub-Saharan Africa.
• In the United States, the overall incidence is lower due to preventive strategies such as vaccination and about 800,000 to 1.4 million people have chronic HBV infection.
• HBV is transmitted via infected body fluids, as with sexual contact, needle sharing, needlestick injury, or perinatally.
• Acute infection is often asymptomatic, when present, symptoms of acute infection are often nonspecific and include fever, fatigue, nausea, vomiting, right upper quadrant tenderness, and jaundice.
• Fulminant hepatitis occurs in < 1% of patients and is the most common cause of death.
• The risk of developing chronic infection is inversely related to age at the time of the initial infection; about 90% of infant infections, 25%-50% of infections in children aged 1-5 years, and < 5% of infections in older children and adults result in chronic disease.
• Extrahepatic manifestations can occur with acute infection and include serum sickness-like reaction and Guillain-Barre syndrome.

Evaluation

• Consider the diagnosis of hepatitis B virus infection in any patient presenting with right upper quadrant tenderness and abnormal liver function tests.
• Confirm the diagnosis using serologic testing and HBV viral load testing. The hepatitis B viral serologic panel includes the following:
  • hepatitis B surface antigen (HBsAg)
  • hepatitis B surface antibody (HBsAb)
  • hepatitis B core immunoglobulin M (HBcIgM)
  • hepatitis B core antibody
  • hepatitis B "e" antigen (HBeAg)
  • hepatitis B "e" antibody (HBeAb)
• Acute infection is defined by a positive HBsAg with a positive HBcIgM.
• Additional testing that may help determine the disease severity, the disease stage, and the need for treatment includes:
  • hepatitis B viral load
  • liver function tests
• Screen patients diagnosed with hepatitis B infection for coinfections including hepatitis C virus, hepatitis D virus, and HIV.

Management

• Acute HBV infection resolves spontaneously in > 95% of patients and treatment is typically not needed.
• Consider treatment for patients with fulminant hepatitis or protracted severe acute hepatitis B (increase in INR, severe jaundice > 4 weeks) (AASLD Grade III) with
  • lamivudine or telbivudine if anticipated duration of treatment is short.
  • entecavir or tenofovir preferred for all other situations.
• For patients with fulminant hepatitis also consider referral to a transplant center.
• Vaccination is recommended for all children aged 0-18 years, and in United States vaccination should be offered to all unvaccinated individuals, particularly those at high risk for infection.
• Recommendations for postexposure prophylaxis vary with the host immune status and the type of exposure and may include the use of hepatitis B immunoglobulin, vaccination, or both.