HEPATITIS B

INTRODUCTIONS
Hepatitis is an inflammation of the liver. The condition can be self-limiting or can progress to fibrosis (scarring), cirrhosis or liver cancer. Hepatitis viruses are the most common cause of hepatitis in the world but other infections, toxic substances (e.g. alcohol, certain drugs), and autoimmune diseases can also cause hepatitis.
There are 5 main hepatitis viruses, referred to as types A, B, C, D and E. These 5 types are of greatest concern because of the burden of illness and death they cause and the potential for outbreaks and epidemic spread. In particular, types B and C lead to chronic disease in hundreds of millions of people and, together, are the most common cause of liver cirrhosis and cancer.
Hepatitis A and E are typically caused by ingestion of contaminated food or water. Hepatitis B, C and D usually occur as a result of parenteral contact with infected body fluids. Common modes of transmission for these viruses include receipt of contaminated blood or blood products, invasive medical procedures using contaminated equipment and for hepatitis B transmission from mother to baby at birth, from family member to child, and also by sexual contact.
Acute infection may occur with limited or no symptoms, or may include symptoms such as jaundice (yellowing of the skin and eyes), dark urine, extreme fatigue, nausea, vomiting and abdominal pain.

TYPES OF HEPATITIS VIRUSES
Scientists have identified 5 unique hepatitis viruses, identified by the letters A, B, C, D, and E. While all cause liver disease, they vary in important ways.

Hepatitis A virus (HAV) is present in the faeces of infected persons and is most often transmitted through consumption of contaminated water or food. Certain sex practices can also spread HAV. Infections are in many cases mild, with most people making a full recovery and remaining immune from further HAV infections. However, HAV infections can also be severe and life threatening. Most people in areas of the world with poor sanitation have been infected with this virus. Safe and effective vaccines are available to prevent HAV.

Hepatitis B virus (HBV) is transmitted through exposure to infective blood, semen, and other body fluids. HBV can be transmitted from infected mothers to infants at the time of birth or from family member to infant in early childhood. Transmission may also occur through transfusions of HBV-contaminated blood and blood products, contaminated injections during medical procedures, and through injection drug use. HBV also poses a risk to healthcare workers who sustain accidental needle stick injuries while caring for infected-HBV patients. Safe and effective vaccines are available to prevent HBV.

Hepatitis C virus (HCV) is mostly transmitted through exposure to infective blood. This may happen through transfusions of HCV-contaminated blood and blood products, contaminated injections during medical procedures, and through injection drug use. Sexual transmission is also possible, but is much less common. There is no vaccine for HCV.

Hepatitis D virus (HDV) infections occur only in those who are infected with HBV. The dual infection of HDV and HBV can result in a more serious disease and worse outcome. Hepatitis B vaccines provide protection from HDV infection.

Hepatitis E virus (HEV) is mostly transmitted through consumption of contaminated water or food. HEV is a common cause of hepatitis outbreaks in developing parts of the world and is increasingly recognized as an important cause of disease in developed countries. Safe and effective vaccines to prevent HEV infection have been developed but are not widely available.

Hepatitis B is an infection of the liver. It can cause scarring of the organ, liver failure, and cancer. It can be fatal if it isn’t treated.
It’s spread when people come in contact with the blood, open sores, or body fluids of someone who has the hep B virus.
The good news is that most cases of the disease don’t last a long time. Your body fights it off within a few months, and you’re immune for the rest of your life. That means you can't get it again.

PROGNOSIS AND GEOGRAPHICAL DISTRIBUTION
The number of people who get this disease is down, the CDC says. Rates have dropped from an average of 200,000 per year in the 1980s to around 18,000 in 2012. People between the ages of 20 and 49 are most likely to get it.
Only 5% to 10% of adults and children older than 5 who have hepatitis B end up with a chronic infection. The numbers aren’t so good for those younger than 5 (25% to 50%) and even higher for infants infected at birth (90%).
As many as 1.4 million people in the U.S. are carriers of the virus.
Hepatitis B prevalence is highest in sub-Saharan Africa and East Asia, where between 5–10% of the adult population is chronically infected. High rates of chronic infections are also found in the Amazon and the southern parts of eastern and central Europe. In the Middle East and the Indian subcontinent, an estimated 2–5% of the general population is chronically infected. Less than 1% of the population of Western Europe and North America is chronically infected.

SYMPTOMS
Most people do not experience any symptoms during the acute infection phase. However, some people have acute illness with symptoms that last several weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea, loss of appetite, vomiting and abdominal pain. A small subset of persons with acute hepatitis can develop acute liver failure which can lead to death.

In some people, the hepatitis B virus can also cause a chronic liver infection that can later develop into cirrhosis of the liver or liver cancer.

TRANSMISSION
The hepatitis B virus can survive outside the body for at least 7 days. During this time, the virus can still cause infection if it enters the body of a person who is not protected by the vaccine. The incubation period of the hepatitis B virus is 75 days on average, but can vary from 30 to 180 days. The virus may be detected within 30 to 60 days after infection and can persist and develop into chronic hepatitis B.

In highly endemic areas, hepatitis B is most commonly spread from mother to child at birth (perinatal transmission), or through horizontal transmission (exposure to infected blood), especially from an infected child to an uninfected child during the first 5 years of life. The development of chronic infection is very common in infants infected from their mothers or before the age of 5 years.

Hepatitis B is also spread by percutaneous or mucosal exposure to infected blood and various body fluids, as well as through saliva, menstrual, vaginal, and seminal fluids. Sexual transmission of hepatitis B may occur, particularly in unvaccinated men who have sex with men and heterosexual persons with multiple sex partners or contact with sex workers. Infection in adulthood leads to chronic hepatitis in less than 5% of cases. Transmission of the virus may also occur through the reuse of needles and syringes either in health-care settings or among persons who inject drugs. In addition, infection can occur during medical, surgical and dental procedures, through tattooing, or through the use of razors and similar objects that are contaminated with infected blood.
A carrier or someone currently infected with hepatitis B, don’t donate blood, plasma, body organs, tissue, or sperm.
Tell anyone you could infect, whether it’s a sex partner, or your doctor or dentist, that you have it.

HEPATITIS B AND PREGNANCY
Pregnant women can pass the virus to the baby at birth. It’s less likely to happen during your pregnancy.
If a baby has the virus and isn’t treated, he could have long-term liver problems. All newborns with infected mothers should get hepatitis B immune globulin and the vaccine for hepatitis at birth and during their first year of life.

DIAGNOSIS
It is not possible, on clinical grounds, to differentiate hepatitis B from hepatitis caused by other viral agents and, hence, laboratory confirmation of the diagnosis is essential. A number of blood tests are available to diagnose and monitor people with hepatitis B. They can be used to distinguish acute and chronic infections.

Laboratory diagnosis of hepatitis B infection focuses on the detection of the hepatitis B surface antigen HBsAg. WHO recommends that all blood donations be tested for hepatitis B to ensure blood safety and avoid accidental transmission to people who receive blood products.

    Acute HBV infection is characterized by the presence of HBsAg and immunoglobulin M (IgM) antibody to the core antigen, HBcAg. During the initial phase of infection, patients are also seropositive for hepatitis B e antigen (HBeAg). HBeAg is usually a marker of high levels of replication of the virus. The presence of HBeAg indicates that the blood and body fluids of the infected individual are highly contagious.
    Chronic infection is characterized by the persistence of HBsAg for at least 6 months (with or without concurrent HBeAg). Persistence of HBsAg is the principal marker of risk for developing chronic liver disease and liver cancer (hepatocellular carcinoma) later in life.

PREVENTION
To help keep a hepatitis B infection from spreading:
    Get vaccinated (if you haven’t already been infected).
    Use condoms every time you have sex.
    Wear gloves when you clean up after others, especially if you have to touch bandages, tampons, and linens.
    Cover all open cuts or wounds.
    Don’t share razors, toothbrushes, nail care tools, or pierced earrings with anyone.
    Don’t share chewing gum or pre-chew food for a baby.
    Make certain that any needles for drugs, ear piercing, or tattoos -- or tools for manicures and pedicures -- are properly sterilized.
    Clean up blood with one part household bleach and 10 parts water.
A vaccine against hepatitis B has been available since 1982. The vaccine is 95% effective in preventing infection and the development of chronic disease and liver cancer due to hepatitis B.

TREATMENT
People with acute hepatitis B do not require treatment. Rest, drinking lots of fluids and maintaining adequate nutrition are usually all that is needed to manage acute hepatitis B symptoms. In severe cases, hospitalization may be necessary, but this is rare. Chronic hepatitis B is not curable, but it is treatable. The goal of therapy is to reduce the risk of complications, including premature death.

Treatment can help to prevent cirrhosis, liver failure and liver cancer by reducing hepatitis B viral load and the loss of HBeAg (either with or without detection of anti-HBe) while improving liver enzyme levels. Many experts anticipate that medications to cure hepatitis B virus (HBV) will be available, perhaps as early as a few years from now.

Here's a list of the treatments currently available for hepatitis B: 

    Baraclude (entecavir)
    Epivir-HBV (lamivudine)
    Intron A (interferon alfa-2b)
    Hepsera (adefovir dipivoxil)
    Pegasys (peginterferon alfa-2a)
    Vemlidy (tenofovir alafenamide)
    Viread (tenofovir disoproxil fumarate)

Deciding when to start therapy and which treatment to take is largely determined by the phase of chronic HBV a person has. Some factors that are considered are HBeAg status, HBV viral load, ALT levels, liver biopsy results (if conducted) and age. Other health considerations—such as the possibility of pregnancy or certain comorbidities (hepatitis D, HIV)—affect treatment choice. Peginterferon is the only effective treatment for people who are also coinfected with hepatitis D. If coinfected with HIV, the choice of HBV treatment is coordinated with the HIV medications. Baraclude, Epivir, Vemlidy and Viread have anti-HIV activity.  

The American Association for the Study of Liver Diseases (AASLD) maintains some basic guidelines—which were last updated in January 2016—to help patients and their health care providers figure out when to begin treatment and which medications to use:

Treatment for Adults With Chronic Hepatitis B
PHASE/CLINICAL CRITERIA:

Immune-active

    HBeAg – or +
    ALT: ≥ 2 x ULN¹
    Or significant liver damage and viral load >2,000 IU/ml (HBeAg –) or >20,000 IU/ml (HBeAg+)

TREATMENT STRATEGY

    Antiviral therapy is recommended. AASLD advises the following to be tried initially: Baraclude, Pegasys or PegIntron; Viread.
    Although treatment isn’t typically recommended for people with lower ALT levels and viral loads, treatment may be considered if liver disease is severe, or > 40 years old, or family history of hepatocellular carcinoma (HCC), etc.
    In cases of cirrhosis, therapy recommended if viral load is >2,000 IU/ml regardless of ALT level

PHASE/CLINICAL CRITERIA:

Immune-tolerant

    HBeAg +
    ALT: normal

TREATMENT STRATEGY

    Treatment not recommended.
    Treatment may be considered for adults > 40 years old with viral load ≥1,000,000 IU/ml and liver biopsy showing moderate to severe fibrosis or inflammation (evidence regarding this is weak).

PHASE/CLINICAL CRITERIA:

Immune-active persons on NA² therapy who seroconverted from HBeAg positive to anti-HBe

    Anti-HBe +
    ALT: normal
    Viral load: undetectable

TREATMENT STRATEGY

    Continue NA² therapy for at least 12 months of persistently normal ALT and undetectable viral load; alternatively, treat until loss of HBsAg.
    Continue treatment indefinitely for adults with cirrhosis who seroconvert from HBeAg positive to anti-HBe

¹ULN = upper limit of normal

²NA = nucleoside/nucleotide analog (Baraclude, Epivir-HBV, Hepsera, Vimlidy, Viread)

It is important that people with chronic hepatitis B take their medications exactly as prescribed. Missing doses can cause HBV to become resistant to medications. Prematurely stopping medications can also cause HBV viral load and liver enzymes to increase quickly, which can damage the liver and cause severe symptoms. This can also occur in people who have HBV who develop resistance to their medications. In turn, it is very important for people with chronic hepatitis B who are receiving treatment to be monitored frequently and carefully by a health care provider.

Last Revised: January 2, 2017

Source : https://www.hepmag.com/basics/hepatitis-b-basics/hepatitis-b-treatment