Hepatitis B

Today is our topic of discussion Hepatitis B

Hepatitis B

Deinition:

Hepatitis B is an acute systemic infection with major pathology in the liver, caused by hepatitis-B virus (HBV) and transmitted usually by the parenteral route.

Agent factors:

Causative agent:

Hepatitis B virus
[Components of the virus: HBsAg (Hepatitis-B surface antigen), HBcAg (Hepatitis-B core antigen) & HBeAg (Hepatitis B envelope antigen)]

Reservoir of infection:

Man (cases and carriers)

Infective material:

Contaminated blood. Virus is also found in saliva, vaginal fluid and semen

Resistance:

The virus is stable for days on environment. Can be eliminated by autoclaving.

Period of communicability:

During IP and acute phase of the disease until disappearance of HBsAg.

Host factors:

Age:

Young and middle age groups are more susceptible.

High risk groups:

a. Surgeons and other health care personnel

b. Recipients of blood
c. Homosexuals
d. Prostitutes

e. IDUs
f. Infants of HBV carrier mothers

Humoral and cellular response:

Antibodies form in a week or two after onset of jaundice. The appearance of surface antibody signals recovery from HBV infection and development of immunity.

Modes of transmission:

a. Parenteral: Transfusion of infected blood & blood products, contaminated syringes & needles, skin prick, handling of blood and blood products and surgical procedures.
b. Perinatal (from mother to baby at birth)
c. Childhood infections (inapparent infection through close interpersonal contact)

d. Sexual contact

Incubation period:

45 to 180 days (Average 90 days)

Clinical feature:

1. Mild fever, headache, muscle aches, joint pain & weakness
2. Loss of appetite and vomiting
3. Diarrhea or constipation
4. Skin rash

5. Jaundice
6. Most people with chronic hepatitis-B have no symptoms

Investigation:

1. Serum bilirubin

2. SGPT level & serum albumin: Assessment of liver function
3. Blood for HBsAg

4. USG of HBS & pancreas: Echotexture of liver parenchyma and associated structure
5. Liver biopsy: Evidence of cirrhosis

Treatment:

General:

General plan of treatment is same as hepatitis A & E (mentioned earlier).

Specific:

1. Interferon: One injection each week for 4-6 months.diuen Lati
2. Antiviral drugs: Lamivudine and similar drugs.
3. Liver transplant

Complication:

1. Chronic hepatitis

2. Cirrhosis of liver
3. Hepatic encephalopathy

4. Hepatocellular carcinoma

Prevention and control:

Avoiding risk factors:

a. Shared needles
b. Homosexuality & illiegimate heterosexuality
c. Prostitute
d. Professional blood donors

e. Carriers: They should not share razors and tooth brushes; use barrier methods of contraception and should not donate blood

Screening of blood donors & encouraging voluntary blood donation.

Standard safety precautions in hospitals and other health care settings:

To avoid accidental needle puncture & contact with infected body fluids.

Active immunization:

Hepatitis B vaccine

Passive immunization:

Hepatitis B immunoglobulin for immediate protection to exposed positive blood, preferably within 6 hours-
a. Surgeons, nurses & laboratory workers
b. Newborn infants of carrier mothers
c. Sexual contacts of acute hepatitis-B patients

Passive-active immunization

See also :

• Dhaka Medical College Hospital (DMCH)