Overview

• HBV ⇒ double-stranded DNA hepadnavirus
  • Transmitted via sexual contact, blood and vertical transmission (from mother to baby)
  • Contains various viral proteins → core antigen (HBcAg), surface antigen (HBsAg) and envelope antigen (HbeAg - marker of high infectivity)
• HDV ⇒ single-stranded RNA virus coated with HbsAg. Defective virus (requires hepatitis B surface antigen to complete its replication and transmission cycle), that may only co-infect with HBV or superinfect people who are already carriers of HBV
  • Chronic Hep B patient with flare up → suspect Hep D superinfection
• Risk Factors → IV drug use, unscreened blood products, infants of HbeAg-positive mothers, sexual contact with HBV carriers
• Common in southeast asia, africa and mediterranean countries

Making Diagnosis

Clinical Features:

• Incubation period of 3-6 months
• Prodromal Features → malaise, headache, anorexia, N&V, diarrhoea, RUQ pain
• Jaundice
• Dark Urine
  • Due to increased conjugated bilirubin in urine
• Hepatomegaly

Investigations:

• Viral Serology
  • Acute HBV → HBsAg positive + IgM anti-HBcAg
    • HBsAg is first marker to appear and causes production of anti-HBs.
  • Chronic HBV → HBsAg positive + IgG anti-HBcAg. May be HbeAg positive or negative.
  • HBV Cleared → anti-HbsAg antibody positive + IgG anti-HBcAg
    • HbsAg positive indicates acute or chronic infection (ie. still have it). Anti-HbsAg antibody positive indicates immunity through previous immunisation or disease (ie. cleared).
  • Vaccinated against HBV → anti-HbsAg antibody positive (everything else negative, won’t have IgG antibody)
    • Can only get antibodies against HbcAg if had infection, not with vaccination
  • HBeAg → marker of infectivity (higher = more infectious)
  • HDV Infection → PCR used for detection
  • Hepatitis B Serology Table
• LFTs → raised AST, ALT, ALP, Bilirubin
• High PT in severe disease
  • PT = sensitive marker of significatn liver damage