Hepatitis B in Children
What is Hepatitis B?
Hepatitis B is a disease caused specifically by hepatitis B virus. The virus infects the liver and may result in inflammation (swelling) of the liver cells (hepatitis). This results in liver dysfunction. The spectrum of the disease ranges widely from asymptomatic disease or mild jaundice (which subside spontaneously) to chronic infection causing liver failure, permanent liver damage (Cirrhosis) or liver cancer (hepatocellular carcinoma).
How common is Hepatitis B?
Hepatitis B is a disease of public health importance due to its high prevalence. In India the prevalence rate is 2-4% in nontribal area and 10-15% in tribal areas.
How does the disease spread?
Hepatitis B virus spreads through the following routes from one person to another:
Perinatal transmission: from mother to her baby at the time of delivery. The infection rate among infants born to HBeAg-positive mothers is as high as 90 percent. Positive HBeAg test means that the virus is in active state of replication. There is no evidence that caesarean section prevents maternal-infant transmission. Thus, caesarean section should not be routinely recommended for carrier mothers.
To decrease the infection among newborn babies it is recommended to test HBsAg on all pregnant women at the first prenatal visit and repeated late in pregnancy in those at high risk for HBV infection. It is also recommended to provide Hepatitis B vaccine to all babies after birth. In babies born to an infected mother, additional Hepatitis B Immunoglobulin (antibodies to fight infection) should be given ideally within 12 hours of birth.
Sexual route of transmission: Sexual transmission remains the major mode of spread of HBV. It is more common in homosexual relationship and in people with multiple sexual partners. Sexual transmission of hepatitis B can be prevented by vaccination of all adolescents and adults; having steady sex partners and safe sex practice including use of condoms.
Blood transfusion: The risk of transfusion has significantly reduced after strict testing of donated blood. Children requiring multiple transfusions, such as those with haemophilia and Thalassemia, are at increased risk of contracting HBV infection.
Infected needles and syringes: This is common among intravenous drug users who share syringes and needles. Health care workers may get infection from needle stick injuries or through contact with infected blood. Patients may be infected through reused syringes or needles. With the use of disposable syringes and needles and safe injection practice this is declining.
Horizontal transmission: Children may acquire HBV infection through horizontal transmission via minor breaks in the skin or mucous membranes or close bodily contacts with other children or family members. This is one of the main modes of transmission amongst children in India. It can rarely be transmitted via contaminated household articles such as tooth brushes, razors and even toys mainly through saliva. Children in facilities such as remand homes also carry an increased risk of horizontal transmission.
Who should be screened for Hepatitis B infection?
Adolescents who engage in high-risk behaviours. This includes those who use intravenous or intranasal drugs, have unprotected sex with multiple sexual partners, men who have sex with men, and those with a history of sexually transmitted disease.
In addition, all internationally adopted children, household contacts of individuals with HBV infection; infants born to women with HBV infection; pre employment health check up in exposure prone occupations.
How does Hepatitis B manifest and what is its course?
The disease may remain completely silent or manifest 6 weeks to 6 months after exposure (incubation period) with fever, body ache, loss of appetite, sensation of vomiting followed by jaundice and right-upper-abdominal discomfort. Liver function test at this stage will show elevation of liver enzymes (SGPT, SGOT). In some patients there will be no jaundice (anicteric hepatitis). The symptoms and jaundice generally disappear after one to three months. This is the acute presentation. This can be diagnosed by positive HBsAg (surface antigen of virus) and positive anti HBc IgM (antibodies to core antigen). This phase is self limiting and only requires symptomatic treatment and rest. Around 1-5% cases may develop severe disease leading to liver failure. Such patients should be admitted in hospital. They may require intensive care or even liver transplantation. Very sick patients can die during this stage.
What is chronic Hepatitis B infection?
About 10 percent of cases may progress to chronic infection which is defined as persistence of virus in the blood for more than six months. This is diagnosed by positive HBsAg, positive HBc IgG antibodies. These patients may be asymptomatic. Over a due course of time either the virus gets cleared or there is excessive multiplication causing liver damage. The level of viral load can be tested by doing HBV DNA copies in blood.
During the chronic stage of the disease depending on the activity of the virus and the immune status, the disease may be active or inactive.
Cirrhosis (permanent liver damage) appears to be an infrequent complication of HBV infection during childhood. During this stage patient develops signs of liver dysfunction like abdominal distension due to fluid collection (Ascites); blood in vomits (Hematemesis due to high pressure in portal veins and prolonged blood clotting); weight loss and altered sensorium (hepatic encephalopathy). In prolonged disease course, there can be dysfunction of the kidneys (hepatorenal syndrome) or lungs (Hepatopulmonary syndrome). These complications can lead to death. Some patients can develop malignancy (cancer) of the liver which can be fatal.
What are the investigations required in Hepatitis B?
Initial evaluation — Initial evaluation of patients with chronic HBV infection should include:
History: One should assess for risk factors for co-infection with HCV and/or HIV, family history of HBV infection, liver disease, and liver cancer.
Physical examination: The physician will assess for signs of chronic liver disease like enlargement of liver and increase in consistency, jaundice, Ascites, edema (swelling of feet), wasting, and gynaecomastia (enlargement of breast nodules in boys) as well as growth parameters.
Laboratory tests: complete blood count with platelets, liver biochemical tests (SGPT, SGOT total bilirubin, alkaline phosphatase), albumin, prothrombin time (time taken for blood to clot), and tests for HBV replication (HBeAg, anti-HBe, HBV DNA). Screening for liver cancer can be done by ultrasound and serum alpha fetoprotein.
Is it necessary to do a liver biopsy?
Liver biopsy is indicated in those patients who are chronically infected with high viral loads but have SGPT/SGOT values mildly elevated or those who have SGPT/SGOT more than 2 times the upper limit of normal values along with other likely causative problems like fatty liver.
What is the treatment of Hepatitis B infection?
Not all patients will require antiviral treatment and majority will clear the infection by one’s own body immune system or remain silent inactive carriers. The ultimate goal of treatment is to reduce the risks of progression to cirrhosis and hepatocellular carcinoma (HCC). The treatment will depend upon the stage of the disease.
Acute stage: Uncomplicated: supportive care
Complicated (liver failure): intensive care, antiviral in form of oral drugs and occasionally liver transplant.
Patients with high viral loads and liver enzymes > 2 times the upper limit normal will need treatment. Treatment is suggested for most patients who are in immune active phase for at least four to six months. The most common regime is six month course of pegylated interferon alfa-2a, 180 microgram/1.73m2 for 24 weeks, followed by an observation period of 6 to 12 months. Pegylated interferon is used as it has advantage of once a week of administration and prolonged duration of action. Children may experience flu-like symptoms (eg, fever, myalgia, headache, arthralgia and anorexia), which usually remit after a few doses by prophylactic acetaminophen. Bone marrow suppression can be seen in some patients. Treatment with interferon is costly and in developing country this may be limiting factor in its use as first line. Lamivudine is a cheaper option but with lower efficacy and long term issues of developing resistance. Adefovir is approved for use in children more than 12 years of age. Entecavir is approved for use in only in children more than 16 years.
What is the response to treatment?
The maximum efficacy is seen with interferon which is up to 30%. Response to Lamivudine is seen in around 20% cases. But there is high risk of developing resistance to Lamivudine and the disease may again appear.
What is the role of vaccination?
Highly effective vaccine is available for prevention of Hepatitis B infection. The government of India has included in the universal immunization programme in 10 states and there is a need to cover all states for vaccination under universal immunization programme. First dose is given after birth and two further doses are given at 6 and 14 weeks.
What is the risk of transmission from a Hepatitis B positive mother to the child?
The infection rate among infants born to HBeAg-positive mothers is as high as 90 percent and is 35% in HBeAg negative mothers. The risk can be decreased by more than 95% by giving vaccination to the newborn at birth.
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