II. Epidemiology

  1. Transmission (100 fold more infectious than HIV)
    1. Percutaneous (needlestick) exposure
      1. Sharing non-sterile needles
      2. Tattooing
      3. Health care accidents
    2. Blood product exposure
    3. Sexual contact
    4. Perinatal exposure
  2. Prevalence
    1. Endemic in sub-Saharan Africa, China, Southeast Asia
      1. Acquired in early life in endemic areas
      2. Chronic Hepatitis BPrevalence: 5 to 20%
    2. Worldwide Prevalence: 300 million infected
    3. United States: 1.5 million Hepatitis B carriers
  3. Incidence
    1. United States: 100,000 new cases per year

III. Pathophysiology

  1. Hepadnavirus (DNA Virus, 42 nm in size)
    1. Family: Hepadnaviridae
  2. Components
    1. Dane particle (entire virus)
    2. Antigens
      1. HBsAg: Outer surface coat encases virus
      2. HBcAg: Inner nucleocapsid core encases genome
      3. HBeAg: Circulating peptide encoded by core gene
    3. Genome
      1. Covalently closed circular dsDNA (cccDNA)
      2. DNA polymerase (reverse transcriptase)
        1. Required for virus replication
  3. Hardy infectious agent
    1. Stable after 15 years storage at -20 C
    2. Stable on dried glass at room Temperature for 4 weeks
    3. Stable for 4 hours at 60 C
    4. Stable after exposure to antiseptics
      1. Ultraviolet Radiation
      2. Benzalkonium chloride
      3. Alcohol
    5. Inactivated by a few agents
      1. Glutaraldehyde
      2. Formalin
      3. Urea
  4. Hepatitis B Virus present in blood and body secretions
    1. Saliva
    2. Tears
    3. Vaginal secretions
    4. Breast Milk
  5. Timing
    1. Incubation: 60 to 90 days on average

IV. Risk Factors

  1. HIV Infection
  2. Intravenous Drug Abuse
  3. Sexually Transmitted Disease
  4. Hemodialysis patients
  5. Healthcare workers
  6. Travel from endemic areas
    1. Asia and southeast Asia
    2. Pacific Islands
    3. Eskimo
    4. India
    5. Sub-Sahara Africa
    6. Haiti

V. Signs and Symptoms

  1. See Viral Hepatitis
  2. Incidence of symptoms (subclinical in most cases)
    1. Age <5 years: <10%
    2. Age >5 years: 30-50%
  3. Symptoms
    1. Initial acute infection
      1. Nausea
      2. Fatigue (may persist)
      3. Low grade fever
      4. Right Upper Quadrant Abdominal Pain
      5. Myalgia or Arthralgias
      6. Urticaria may also occur
    2. Later acute infection
      1. Jaundice

VI. Differential Diagnosis

VII. Labs: Acute Hepatitis B Infection Screening

  1. See Hepatitis B Serology (includes indications for screening)
  2. Screening (Identifies most cases of Acute Hepatitis B)
    1. HBsAg
    2. xHBc IgM
    3. xHBs IgG (to test for immunity)

VIII. Labs: Evaluation of positive Hepatitis B Screening

  1. See Hepatitis B Serology (see for stages of Hepatitis B infection)
  2. Additional Hepatitis B Serology
    1. Anti-HBc Antibody
    2. HBeAg
    3. Anti-HBe Antibody
    4. HBV DNA
  3. Comorbid infection
    1. Anti-HAV Antibody
    2. Anti-HCV Antibody
    3. Anti-HDV Antibody
    4. HIV Test
  4. Liver Function Tests
    1. Serum transaminases peaks 1-2 weeks before Jaundice
      1. Alanine Aminotransferase (ALT)
      2. Aspartate Aminotransferase (AST)
    2. Serum Bilirubin (rarely exceeds 20 mg/dl)
      1. Increases after serum transaminases increase
    3. Serum Albumin
      1. Decreased in severe liver disease
    4. Prothrombin Time (with INR)
      1. Increased in severe liver disease
  5. Complete Blood Count
    1. Anemia
    2. Lymphocytosis
  6. Evaluation for complications in high risk patients
    1. See Chronic Hepatitis B

IX. Management: Prophylaxis of contacts

X. Management: Acute Hepatitis B

  1. Symptomatic management
  2. Spontaneously resolves in 90% within 3-6 months
  3. Recheck HBsAg at 6 months

XI. Management: Chronic Hepatitis B

  1. Definition: HBsAg positive at 6 months (10%)
  2. Management per Chronic Hepatitis B type
    1. Chronic Hepatitis B Carrier
    2. Chronic Hepatitis B Infection

XII. Complications

XIII. Prognosis: Acute Hepatitis B

  1. Outcome in adults and children over age 5 years
    1. Recovery: 90%
    2. Chronic Active Hepatitis: 10%
    3. Fulminant Hepatitis: <1% (high mortality)
  2. Outcome in children under age 5 years
    1. Chronic infection: 30-90%
  3. Worse prognosis if Hepatitis D also present
    1. Cirrhosis higher risk
    2. Hepatocellular Carcinoma higher risk

XIV. Prevention

  1. See Hepatitis B Postexposure Prophylaxis
  2. Hepatitis B Vaccine
  3. Reactivation of Hepatitis B
    1. More common now with broadening use of tnf agents (e.g. Rheumatoid Arthritis, Crohn's Disease)
    2. Screen for Hepatitis B (HBsAg, HBcAb) before starting tnf agents or Chemotherapy

XVI. References

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