Hepatitis B is an inflammatory disease of the liver caused by the hepatitis B virus (HBV). The hepatitis B virus reproduces in liver cells, but the hepatitis B virus itself is not the direct cause of damage to the liver. Rather, the presence of the hepatitis B virus triggers an immune response from the body as the body tries to eliminate the hepatitis B virus and recover from the infection. This immune response causes inflammation and may seriously injure liver cells. Therefore, there is a balance between the protective and destructive effects of the immune response to the hepatitis B virus. The acute illness causes liver inflammation, vomiting, jaundice, and rarely, death. Chronic hepatitis B may eventually cause cirrhosis and liver cancer.
However, many people don’t realise they have been infected with the hepatitis B virus, because the symptoms may not develop immediately, or even at all. It takes about 40 to 160 days for any symptoms to develop after exposure to the hepatitis B virus. When a person first gets hepatitis B, they are said to have an ‘acute’ infection. Most people are able to eliminate the hepatitis B virus and are cured of the infection. Some are not able to clear the hepatitis B virus and have ‘chronic’ infection with hepatitis B that is usually life-long.
Stages of hepatitis B
Hepatitis B can be acute or chronic. The terms ‘acute’ and ‘chronic’ refer to how long a person has it, not to how serious a condition is. Acute hepatitis B is typically over within three months. Chronic hepatitis B is a long-term disease that can sometimes last for the rest of the affected person’s life. About one adult in ten who gets infected with the hepatitis B virus develops a chronic infection. People with chronic hepatitis B can still pass the virus on to other people, even if it is not causing any symptoms. Around 20% of people with chronic hepatitis B, develop scarring of the liver (cirrhosis), which can take about 20 years to develop, and around 1 in 10 people with cirrhosis will develop liver cancer.
How does hepatitis B spread?
The hepatitis B virus is transmitted by exposure to infected blood or body fluids such as semen and vaginal secretion. However, hepatitis B virus cannot be spread by holding hands, sharing eating utensils or drinking glasses, sneezing, coughing, kissing, hugging, or breastfeeding. Sexual contact is the most common means of transmission, followed by using contaminated needles for injecting illicit drugs, tattooing, body piercing, or acupuncture. Additionally, hepatitis B can be transmitted through sharing toothbrushes and razors contaminated with infected fluids or blood.
Hepatitis B can be spread from infected mothers to their babies at birth. This is the most prevalent means of transmission in regions of the world where hepatitis B rates are high. The rate of transmission of hepatitis B from mother to new-born is very high, and almost all infected infants will develop chronic hepatitis B. Rarely, hepatitis B can be transmitted through transfused blood products, donated livers and other organs. However, blood and organ donors are routinely screened for hepatitis B which typically prevents this type of transmission.
Signs and symptoms of hepatitis B
Hepatitis B virus initially interferes with the functions of the liver by replicating in liver cells, known as hepatocytes. Acute infection with hepatitis B virus is begins with general fatigue, loss of appetite, nausea, vomiting, mild fever, body aches, dark urine, and then progresses to development of jaundice. It has been noted that itchy skin has been an indication as a possible symptom of all hepatitis virus types. The illness lasts for a few weeks and then gradually improves in most affected people. Chronic infection with hepatitis B virus either may be asymptomatic or may be associated with a chronic inflammation of the liver, leading to cirrhosis over a period of several years. This type of infection dramatically increases the incidence of liver cancer (hepatocellular carcinoma). Significant amounts of scarring and cirrhosis lead to liver dysfunction. Symptoms may include: weakness, fatigue, loss of appetite, weight loss, breast enlargement in men, rash on the palms, poor blood clotting, and Prominent blood vessels on the skin. Several complications occur in advanced cirrhosis: Confusion and even coma (encephalopathy) results from the inability of the liver to detoxify certain toxic substances.
Causes of hepatitis B
Hepatitis B is caused by the hepatitis B virus. It can spread between people by contact with an infected person’s blood or other body fluids, for example, semen or vaginal fluid. The hepatitis B virus can survive outside your body for up to seven days. During that time, the hepatitis B virus can still cause infection if it enters the body of a person who isn’t immune.
Diagnosis of hepatitis B
The diagnosis of hepatitis B can be made only with specific hepatitis B virus blood tests. These tests are known as hepatitis ‘markers’ or ‘serology.’ The tests, for detection of hepatitis B virus infection is called assays. Markers found in the blood can confirm hepatitis B infection and differentiate acute from chronic infection. These markers or substances produced by the hepatitis B virus (antigens) and antibodies produced by the immune system to fight the virus. If you feel you have been exposed to the hepatitis B virus, contact your Doctor.
Prevention of hepatitis B
There is a vaccine that is thought to be 95% effective in preventing hepatitis B. Vaccination would usually only be recommended for people in high-risk groups, such as: people who inject drugs or have a sexual partner who injects drugs, people who change their sexual partner frequently, people travelling to or from a part of the world where hepatitis B is widespread. Pregnant women are also screened for hepatitis B, and if they are infected their baby can be vaccinated shortly after birth. Hepatitis B is a preventable disease. Vaccination and post-exposure prophylaxis have significantly reduced rates of infection. Risk can also be reduced by avoiding unprotected sex, contaminated needles, and other sources of infection.
Adults in high risk situations also are advised to receive hepatitis B vaccine. This includes: health care workers, dentists, intimate and household contacts of patients with chronic hepatitis B infection, public safety workers who may be exposed to blood, men who have sex with men, individuals with multiple sexual partners, dialysis patients, and injectable drug users, persons with chronic liver disease, residents and staff in institutions that care for persons with developmental disabilities, persons infected with HIV, persons who require repeated transfusions or blood products.
Treatment of hepatitis B
Acute infection with hepatitis B usually does not require treatment. In rare cases, however, the infection may cause life-threatening liver failure. Patients with liver failure due to acute hepatitis B should be evaluated for liver transplantation. There is currently no specific treatment for acute hepatitis B, other than using painkillers to relieve symptoms.
Treatment of chronic infection may be necessary to reduce the risk of cirrhosis and liver cancer. Chronic hepatitis B can be treated using a combination of antiviral medications designed to slow the spread of the hepatitis B virus and prevent damage to the liver. These patients are watched carefully and given periodic blood tests. Doctors will recommend treatment if there are signs that the hepatitis B virus is beginning to cause damage or if the viral load is high. In chronic hepatitis B, the goal of treatment is to reduce the risk of complications including cirrhosis and liver failure.
Medications can reduce the number of hepatitis B viruses in the body and may be able to eliminate the hepatitis B virus from the bloodstream. Logically, this should lead to them having a low rate of progression to. Even in people who clear the hepatitis B virus from their blood, low numbers of hepatitis B viruses still live in the liver and other cells. Thus, the medications do not cure the disease, but they can prevent or delay complications and symptoms. People who have a good response to treatment can still transmit the hepatitis B virus. The medications in current use for chronic hepatitis B include the interferon and nucleoside/nucleotide analogues.