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Lecture on Hepatitis B Virus

Posted Feb. 18, 2014. Pathology

Hepatitis B virus also called as serum hepatitis virus.

  • This is hepatotropic virus because it proliferate in the liver.
  • Hemophilic patient with multiple transfusions serum reacted with serum of Australian patient ,so this is called as Australia antigen

Epidemiology

  1. Long incubation period
    1. Asymptomatic period is from 4 to 26 weeks.
    2. Average time is 1.5 to 2 months.
  2. Acute disease
    1. This may last for weeks to months.

HBV causes hepatitis in

  1. Human .
  2. Woodchucks and ducks.
  3. Ground and tree squirrel.

HBV can cause

  1. chronic hepatitis.
  2. Scarring of liver leading to cirrhosis.
  3. Liver failure.
  4. Liver cancer.
  5. Ultimately leads to death.
  1. Mode of Spread of the disease
    1. Parental mode like blood, blood products, and needle pricks.
    2. It can spread by through semen and saliva.
    3. Vertical transmission can occur through mothers.
    4. Dialysis patients are at higher risk.
    5. Health workers are also high risk group.
    6. In 1/3 of the cases source is unknown.
    7. Drug addicts are also high risk group.

Source of spread

  1. Blood and blood products.
  2. Body fluids :
    1. Semen.
    2. Vaginal secretions.
    3. Saliva.
    4. Open sore .
    5. Breast milk.
  1. Virus present in
    1. It is present in the last days of incubation period in the blood.
    2. It is present in acute and chronic stages of disease.
    3. This is present in physiologic and pathologic fluids except feces.

Infectivity of various materials

  1. Blood is ++++.
  2. Body fluids are + to +++.
  3. Stool is negative.

Infective hepatocytes can :

  • Synthesize and secrete massive amount of HBS which appears in cells and serum.
  • This may occur with or without replication of infectious viron.

rong>Who poses more risk

  1. Health workers and dialysis patients are more at risk.

Structure of HB virus

  • This is DNA virus.
  • Complete virus particle is called Dane particle and it is 42 nm in diameter.
  • On E/M Virus particle consists of :
    • Sphere 20 nm D.
    • Tubules 20 × 100 nm.
    • Dane particle which consists of DNA + coat proteins.
    • Sphere and tubules are excessive proteins and these are surface antigens HBs proteins.
    • These sphere and tubules (HBs Ag) are not infective.
  • HBV genome is double stranded DNA.
  • HBV antigens are :
    • HBs antigen.
    • HBc antigen
    • HBe antigen.
  • HBV antibodies are :
    • Anti-HBs.
    • Anti-HBc
    • Ant-HBe
  • There are few Dane particles in the serum as compared to surface antigen HBs.

Outcome of HBV infection

  1. There may be asymptomatic carrier who are without obvious disease.
  2. Patient may have acute hepatitis.
  3. Patient may go into chronic stage as chronic hepatitis.
    1. Chronic hepatitis may be non-progressive.
    2. Chronic hepatitis may be progressive with development of cirrhosis.
  4. Patient may develop fulminant hepatitis with massive necrosis.

Chronic Carrier

  • Following is the criteria to label patient as Carrier.
    1. These patient has no signs and symptoms.
    2. Liver function tests are normal.
    3. HBs antigen is positive.
    4. These patients has increased risk for liver cell carcinoma. This risk may be be 273 times

Post exposure prophylaxis

  1. If there is percutaneous prick then give hepatitis B immunoglobulin (HBIG) 0.06 ml/kg IM or 5 ml as single dose.
  2. Can give vaccine 1.0 ml within 7 days.
  3. Vaccine alone may be of value in poor patients (A.J.Med.1989).

Perinatal exposure

  1. Give HBIG 0.5 ml IM within 12 hours of exposure.


Sexual exposure

  1. Give 0.06 ml/ kg or 5 ml IM within 14 days of contact.

Risk and prevention in pregnant mothers

  1. If mother is HBs positive then infectivity for newborn is 40 %.
  2. If mother is HBs positive and HBe positive then infectivity for new born is 85 to 95 %.
  3. If newborn given vaccine or HBIG after 7 days then it has no value.
  4. So HBIG + vaccine should be given to newborn within 2 to 12 hours. Maximum can be delayed up to 48 to 72 hours.

Diagnosis and various panel for various conditions of HBV infection

  1. Screening panel consists of :
    1. HBs Ag.
    2. Anti-HBs.
    3. This is panel is used for :
      1. Blood donors.
      2. Perinatal.
      3. Dialysis centers.
  2. HBV monitoring panel consists of :
    1. HBs Ag.
    2. HBe Ag.
    3. Anti-HBe Abs
    4. This panel is used for :
      1. Patients with HBV infection.
      2. Define degree of infectivity.
      3. Potential for chronic hepatitis.
      4. When there is seroconversion from HBe-Ag to HBe- Abs is good prognostic factor.