Hepatitis B

 

Definition of Hepatitis B

• An infection of hepatocytes by the hepatitis B virus

 

Epidemiology of Hepatitis B

• Incidence low in UK and USA: about 0.5%.
  • High in Africa, Middle East, Far East: about  10-15%
• Blood, sexual and vertical transmission
• 350 million chronic carriers worldwide

 

Cause of Hepatitis B

• Hepatitis B virus: a DNA virus with reverse transcriptase activity

 

Presentations of Hepatitis B

• Often subclinical or flu-like illness
• Acute presentation (if symptoms noted at all)
  • Jaundice (only 30-50%)
    • Dark urine/pale stools due to intrahepatic cholestasis (if jaundice severe enough)
  •  Serum-sickness-like syndrome (occasionally)
    • Rash, polyarthritis, fever
  • Arthritis or immune-complex-mediated renal failure (rarely)
  • Tender hepatomegaly
• Chronic
  • Chronic liver disease – either compensated or decompensated

 

 

Differential diagnosis of Hepatitis B

• Other causes of acute hepatitis
  • Drugs, Hep A, Infection, alcohol
• Other causes of chronic liver disease (see chronic liver disease page)

 

Staging of and interpreting viral markers of Hepatitis B (serology)

• Click here for full explanation of how to interpret Hep B serology

 

Video on interpreting viral serology in hepatitis B

Initial management of acute Hepatitis B

• Blood tests:
  • FBC
  • LFTs
  • Clotting screen
  • Viral screen including HBsAg, HBV DNA, HBeAg, HIV, HCV, Hepatitis Delta
  • Autoimmune screen
• Ultrasound liver
• Treatment is discussed further below but is not normally undertaken in the acute phase other than supportive measures and alcohol avoidance.

 

Further management of chronic Hepatitis B

• Investigate as per other causes of chronic liver disease (see CLD page)
• HBV vaccine is available
• Treatment
  • HBV is not yet curable and treatment aims for viral load suppression and to prevent liver cirrhosis and its complications.
  • Decision to treat takes into account a number of factors including degree of fibrosis, HBV DNA levels, comorbidities, likelihood of treatment success.
• Treatment options
  • Pegylated interferon
    • No resistance develops
    • Finite duration of therapy
    • Less well tolerated than nucleoside or nucleotide analogue due to side-effect profile
    • Only moderate antiviral activity
  • Nucleoside (Lamivudine, Entecavir) and Nucleotide (Tenofovir) analogues
    • Potent antiviral effects
    • Few side-effects
    • Risk of resistance with some drugs

 

Complications of Hepatitis B

• Fulminant hepatitis from acute infection
• Chronic infection which can lead to chronic liver disease, cirrhosis and its complications including HCC (see decompensated CLD pages: ascites, SBP, encepalopathy, varices, hepatorenal syndrome)

 

Prognosis of Hepatitis B

• Acutely, mortality 1%.
• About 10% will become chronically infected, and will either be asymptomatic carriers (non-infective, no liver damage) or have chronic hepatitis (which leads to cirrhosis and is infective)

 

Click here for medical student OSCE and PACES questions about Hepatitis B

Common Hepatitis B exam questions for medical students, finals, OSCEs and MRCP PACES

Click here to download free teaching notes on hepatitis B: Hepatitis B

Perfect revision for medical students, finals, OSCEs and MRCP PACES