VIRAL HEPATITIS
()Hepatitis means inflammation of the liver.
Many illnesses and conditions can cause inflammation of the liver, for example, drugs, alcohol, chemicals, and autoimmune diseases.
() There are several hepatitis viruses; they have been named types A, B, C, D, E, F (not confirmed), and G.
() It is a common cause of jaundice
() The viruses cause illnesses with similar clinical and pathological features and which are frequently anicteric or even asymptomatic.
Causes
ACommon:
Hepatitis A
Hepatitis B ± hepatitis D
Hepatitis C
Hepatitis E
Less common:
Cytomegalovirus
Epstein-Barr virus
Rare
Herpes simplex
Yellow fever
Clinical features
() A non-specific prodromal illness characterised by headache, myalgia, arthralgia, nausea and anorexia usually precedes the development of jaundice by a few days to 2 weeks.
() Vomiting and diarrhoea may follow, and abdominal discomfort is common.
()Dark urine and pale stools may precede jaundice.
() There are usually few physical signs. The liver is often tender but only minimally enlarged. Occasionally, mild splenomegaly and cervical lymphadenopathy are seen. These are more frequent in children or those with Epstein-Barr virus infection.
() Jaundice may be mild and the diagnosis may be suspected only after finding abnormal liver blood tests in the setting of non-specific symptoms. Symptoms rarely last longer than 3-6 weeks.
Investigations
A hepatitic pattern of LFTs develops, with serum transaminases typically between 200 and 2000 U/L.
The ALP rarely exceeds twice the upper limit of normal.
Prolongation of the prothrombin time indicates the severity of the hepatitis but rarely exceeds 25 seconds.
The white cell count is usually normal with a relative lymphocytosis.
Serological tests confirm the aetiology of the infection.
Management
Most individuals do not need hospital care.
Drugs such as sedatives and narcotics, which are metabolised in the liver, should be avoided.
No specific dietary modifications are needed.
Alcohol should be avoided during the acute illness.
Elective surgery should be avoided in cases of acute viral hepatitis, as there is a risk of post-operative liver failure.
Liver transplantation is very rarely indicated for acute viral hepatitis complicated by liver failure, but is commonly performed for complications of cirrhosis resulting from chronic hepatitis B and C infection.
Hepatitis A
The hepatitis A virus (HAV) belongs to the picornavirus group of enteroviruses.
HAV is highly infectious and is spread by the faecal-oral route. Infected individuals, who may be asymptomatic, excrete the virus in faeces for about 2-3 weeks before the onset of symptoms and then for a further 2 weeks or so.
Infection is common in children but often asymptomatic, and so up to 30% of adults will have serological evidence of past infection but give no history of jaundice.
Infection is also more common in areas of overcrowding and poor sanitation. In occasional outbreaks water and shellfish have been the vehicles of transmission.
a chronic carrier state does not occur.
Investigations
Anti-HAV is important in diagnosis, as HAV is only present in the blood transiently during the incubation period. Excretion in the stools occurs for only 7-14 days after the onset of the clinical illness.
Anti-HAV of the IgM type, indicating a primary immune response, is already present in the blood at the onset of the clinical illness and is diagnostic of an acute HAV infection. Titres of this antibody fall to low levels within about 3 months of recovery.
Anti-HAV of the IgG type is of no diagnostic value as HAV infection is common and this antibody persists for years after infection, but it can be used as a marker of previous HAV infection. Its presence indicates immunity to HAV.
Managment
Individuals can be given substantial protection from infection by active immunisation with an inactivated virus vaccine, which indicated in individuals with chronic hepatitis B or C infections.
Immediate protection can be provided by immune serum globulin if this is given soon after exposure to the virus.
Immune serum globulin can be effective in an outbreak of hepatitis, in a school or nursery, as injection of those at risk prevents secondary spread to families. People travelling to endemic areas are best protected by vaccination.
Acute liver failure is rare in hepatitis A (0.1%) . However, HAV infection in patients with chronic liver disease may cause serious or life-threatening disease.
Hepatitis B
a hepadnavirus that can cause both acute and chronic hepatitis, chronic hepatitis develops in the 5-10% of adults
Hepatitis B infection affects 300 million people and is one of the most common causes of chronic liver disease and hepatocellular carcinoma world-wide.
The hepatitis B virus consists of a core containing DNA and a DNA polymerase enzyme needed for virus replication. The core of the virus is surrounded by surface protein .
Humans are the only source of infection.
Hepatitis B may cause an acute viral hepatitis; however, the acute infection is often asymptomatic, particularly when acquired at birth.
Many individuals with chronic hepatitis B are also asymptomatic. Chronic hepatitis, associated with elevated serum transaminases, may occur and can lead to cirrhosis, usually after decades of infection .
() IP about 90 days.
() Acute hepatitis B refers to newly acquired infections, Affected individuals notice symptoms approximately 1 to 4 months after exposure to the virus.
() Chronic hepatitis B is an infection with HBV that lasts longer than 6 months.
Source of hepatitis B infection and risk of chronic infection
Horizontal transmission (10%):
Injection drug use
Infected unscreened blood products
Tattoos/acupuncture needles
Sexual (homosexual and heterosexual)
Close living quarters/playground play as a toddler
The virus may be transmitted when infectious fluids contact with broken skin or a mucous membrane.
Vertical transmission (90%):
HBsAg-positive mother
Breast feeding
People who are at an increased risk of being infected with the hepatitis B virus include the following:
1- Men or women who have multiple sex partners, especially if they don t use a condom
2- homosexual
3- Men or women who have sex with a person infected with hepatitis B virus
4- People with other sexually transmitted disease.
5- People who inject drugs with shared needles
6- People who receive transfusions of blood or blood products 7- People who undergo dialysis for kidney disease 8- mentally handicapped people and their attendants, caregivers, and family members 9- Health care workers who are stuck with needles or other sharp instruments contaminated with infected blood 10- Infants born to infected mothers
11- In some cases, the source of transmission is never known.