Posted Feb. 18, 2014.
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
- Long incubation period
- Asymptomatic period is from 4 to 26 weeks.
- Average time is 1.5 to 2 months.
- Acute disease
- This may last for weeks to months.
HBV causes hepatitis in
- Human .
- Woodchucks and ducks.
- Ground and tree squirrel.
HBV can cause
- chronic hepatitis.
- Scarring of liver leading to cirrhosis.
- Liver failure.
- Liver cancer.
- Ultimately leads to death.
- Mode of Spread of the disease
- Parental mode like blood, blood products, and needle pricks.
- It can spread by through semen and saliva.
- Vertical transmission can occur through mothers.
- Dialysis patients are at higher risk.
- Health workers are also high risk group.
- In 1/3 of the cases source is unknown.
- Drug addicts are also high risk group.
Source of spread
- Blood and blood products.
- Body fluids :
- Vaginal secretions.
- Open sore .
- Breast milk.
- Virus present in
- It is present in the last days of incubation period in the blood.
- It is present in acute and chronic stages of disease.
- This is present in physiologic and pathologic fluids except feces.
Infectivity of various materials
- Blood is ++++.
- Body fluids are + to +++.
- 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
- 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 :
- There are few Dane particles in the serum as compared to surface antigen HBs.
Outcome of HBV infection
- There may be asymptomatic carrier who are without obvious disease.
- Patient may have acute hepatitis.
- Patient may go into chronic stage as chronic hepatitis.
- Chronic hepatitis may be non-progressive.
- Chronic hepatitis may be progressive with development of cirrhosis.
- Patient may develop fulminant hepatitis with massive necrosis.
- Following is the criteria to label patient as Carrier.
- These patient has no signs and symptoms.
- Liver function tests are normal.
- HBs antigen is positive.
- These patients has increased risk for liver cell carcinoma. This risk may be be 273 times
Post exposure prophylaxis
- If there is percutaneous prick then give hepatitis B immunoglobulin (HBIG) 0.06 ml/kg IM or 5 ml as single dose.
- Can give vaccine 1.0 ml within 7 days.
- Vaccine alone may be of value in poor patients (A.J.Med.1989).
- Give HBIG 0.5 ml IM within 12 hours of exposure.
- Give 0.06 ml/ kg or 5 ml IM within 14 days of contact.
Risk and prevention in pregnant mothers
- If mother is HBs positive then infectivity for newborn is 40 %.
- If mother is HBs positive and HBe positive then infectivity for new born is 85 to 95 %.
- If newborn given vaccine or HBIG after 7 days then it has no value.
- 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
- Screening panel consists of :
- HBs Ag.
- This is panel is used for :
- Blood donors.
- Dialysis centers.
- HBV monitoring panel consists of :
- HBs Ag.
- HBe Ag.
- Anti-HBe Abs
- This panel is used for :
- Patients with HBV infection.
- Define degree of infectivity.
- Potential for chronic hepatitis.
- When there is seroconversion from HBe-Ag to HBe- Abs is good prognostic factor.