Based on viral, immunologic and epidemiologic consideration, five types of viral hepatitis are recognized (i.e. hepatitis A, B, C, D and E).
- Causative agent – hepatitis A virus is an RNA virus, 27nm in diameter and is classified as a picornavirus.
- Mode of infection – it is through feco-oral route, contaminated food and water; through fingers and feeding utensils.
- Incubation period – 15 to 30 days. Average of 25 to 30 days.
Symptoms of Hepatitis A
- Onset is generally acute.
- Initially patient has moderate fever, malaise, loss of appetite and nausea and abdominal pain.
- After initial phase patient passes dark colored urine, stools are clay colored.
- Sclera and skin shows icterus (yellowish discoloration of sclera) which may last for 1 to 4 weeks.
- Carrier state is unusual.
Hepatitis A Diagnosis
- Serological tests for diagnosis of hepatitis A are available (anti HAV and IgM anti HAV).
- IgM anti-HAV indicates recent infection.
- ALT SGPT is high. ALT Levels are high in first week of illness.
- Transminase levels remain elevated for 1 to 3 weeks.
- Prophylaxis: Pooled immunoglobulin is given intramuscular which protects personal contacts and household members.
- Causative agents- hepatitis B virus is DNA containing virus, 42nm in diameter.
- Mode of transmission- usually indirect, through parentral route from hepatitis B virus contaminated blood transfusion.
- Sharing of contaminated needles and shaving razors.
- As virus is found in other biological fluids such as blood, urine, breast milk etc. it may be transmitted via transcutaneous route through abrasions in skin.
- Vertical transmission by mother to fetus is possible.
- Incubation period is 45 to 60 days.
Symptoms of Hepatitis B
- Onset is gradual
- Mild loss of appetite
- Nausea and vomiting are uncommon
The illness may follow any of the following courses:
- Asymptomatic infection with minimal liver damage.
- Acute hepatitis.
- Leading to chronic carrier state.
- Chronic hepatitis may evolve into chronic persistent or chronic active hepatitis.
Diagnosis: Various immunologic assays are available for specific diagnosis of hepatitis B virus (HBV) i.e. HBsAG.
- Causative agents- hepatitis C virus is a single stranded RNA virus belonging to flavivirus family.
- Modes of transmission- more than 80% of cases of post transfusion hepatitis in some series were attributed to hepatitis C.
- Mainly transmitted through blood and blood products but may also be transmitted sexually.
- Peri-natal transmission may also occur.
- Incubation period varies from 2 to 24 weeks.
Symptoms Of Hepatitis C
- Onset is gradual and presents with jaundice.
- Malaise appears mild compared to hepatitis B and may even be asymptomatic.
- 50% of patients may develop chronic liver disease such as cirrhosis or even hepatocellular cancer.
Hepatitis C Diagnosis
- Serological test for anti-HCV (hepatitis C virus) are now available.
- There may be cyclic elevation of transaminase level.
- Causative agents- hepatitis delta virus is a 35-37nm defective RNA fragment and delta protein antigen.
- It cannot cause disease alone, but requires hepatitis B as a helper virus which is coated on it.
- Infection with HDV (hepatitis D virus) in persons already infected with HBV may get fulminant illness.
- Chronic asymptomatic carriers of HBV are at risk of developing delta hepatitis and subsequent chronic liver disease and cirrhosis.
- Mode of transmission is by blood transfusion or products or through mucous membrane inoculation.
- Incubation period is 2 to 8 weeks.
- Investigations- anti HDV antibody can be demonstrated.
- Hepatitis E virus (HEV) is an RNA virus similar to a calicivirus.
- Incubation period is 15 to 60 days.
- Transmission is by feco-oral route.
- Incidence is higher in pregnant women and adults compared with children.
- Acute illness is associated with icterus (yellow discoloration of sclera), loss of appetite, fever and malaise.
- Serological tests for detecting HEV antibody are possible.
- Passive immuno-prophylaxis is not effective.
Treatment For Viral Hepatitis
- No specific therapy.
- Rest in bed is recommended till transaminase levels are high.
- Good nutritious diet rich in carbohydrate and protein should be given.
- Fats should be restricted.
- If chronic active hepatitis has already set in, corticosteroid may be used to suppress immune mechanisms.
- Chronic persistent hepatitis is however a benign condition and does not require any specific treatment.