Hepatitis A is an inflammation of the liver caused by the hepatitis A virus (HAV). The virus spreads…
What is hepatitis?
There are several possible causes of hepatitis, with viral infections causing the large majority of cases. The signs and symptoms of hepatitis are due to the inflamed liver's inability to work properly. Many people with hepatitis feel no symptoms at all and may not know they have the condition. In some cases, if hepatitis is not treated, it can lead to long-term complications.
Types and causes
The most common cause of hepatitis is viral. The liver can become inflamed for a number of other reasons, including autoimmune disorders and the effect of various substances, such as alcohol or medications.
Several kinds of viruses can cause hepatitis. Even though the initial symptoms are essentially the same, each kind of virus has its own characteristic features.
Hepatitis A is caused by the hepatitis A virus (HAV), which spreads through contaminated food or water, or through direct contact with an infected person. About 30% of adults and up to 90% of children show no signs or symptoms. There is no specific treatment for hepatitis A; the infection normally goes away by itself after a couple of months. The body usually develops immunity to the virus, so is unlikely to develop another infection in the future.
In rare cases, complications may occur, especially in people with weakened immune systems. The best protection against hepatitis A is a vaccine that is often recommended prior to travelling to countries where the virus is prevalent. In many countries, children are now vaccinated against hepatitis A at an early age.
Hepatitis B, caused by the hepatitis B virus (HBV), can result in serious health issues including liver failure and death. About two billion people are infected with hepatitis B; it is responsible for over a million deaths every year. The virus can spread in several ways, including sexual contact, blood-to-blood contact and from mother to child at birth.
Hepatitis B can occasionally lead to a chronic infection. In such cases, antiviral medications taken over several years can help to clear the infection.
Hepatitis B can be prevented with vaccination and by taking care to avoid contact with infected people's blood.
Hepatitis C is caused by the hepatitis C virus (HCV). It affects an estimated 130-200 million people worldwide. Hepatitis C can result in serious health issues, including liver damage, liver cancer and death. The virus spreads mostly through blood-to-blood contact. In developed countries, most cases of hepatitis C infection occur through sharing of needles for injected (intravenous) drug use.
Treatment for hepatitis C is effective in about half of all patients. However, new treatments coming into use may greatly improve treatment success rates in coming years. There is currently no vaccine for hepatitis C. The best way of preventing contracting it is by taking care to avoid contact with infected people's blood.
The hepatitis D virus (HDV) affects an estimated 15-20 million people worldwide. It only causes disease in the presence of the hepatitis B virus. When HDV does cause disease, it can be quite serious; it is the type of hepatitis most likely to cause complications and liver damage.
HDV is transmitted in similar ways to the hepatitis B virus (sexual contact, blood-to-blood contact). Often, the two viruses are transmitted at the same time. Treatment for hepatitis B may not affect the hepatitis D virus directly, but a successful eradication of hepatitis B (or a vaccination against hepatitis B) will also help prevent liver disease related to the hepatitis D virus.
The hepatitis E virus, like the hepatitis A virus, is transmitted mainly through contaminated food or water, or through direct contact with an infected person. It normally goes away by itself after a few weeks, although in rare cases liver problems can occur. Hepatitis E affects an estimated 20 million people worldwide and is responsible for about 56,000 deaths a year. It is mostly found in regions with poor sanitation. A vaccine for hepatitis E was announced in China in 2011, but is still not commercially available worldwide.
Other hepatitis viruses
Other viruses including Epstein-Barr virus, cytomegalovirus, and some herpes viruses can cause hepatitis, which is often temporary.
Autoimmune hepatitis is an uncommon condition in which the body's immune system mistakenly identifies liver cells as a threat and targets them for destruction. The exact causes of autoimmune hepatitis are unknown (as is the case with many other autoimmune diseases of the body). Women are more likely to be affected than men. Genetics and environmental factors (certain medications and infections) appear to increase the chance of developing autoimmune hepatitis, as do pre-existing autoimmune conditions such as Crohn's disease or coeliac disease.
One of the liver's many roles is to process alcohol and break it down into harmless smaller molecules. If there is too much alcohol in the blood, the liver is not able to keep up. Excessive alcohol consumption can damage the liver and result in alcoholic hepatitis. It is one of the many health problems caused by alcoholism.
Ischaemic hepatitis is caused by insufficient blood supply to the liver. It is usually caused by problems with the heart, the blood vessels or lung conditions.
Idiopathic neonatal hepatitis
Neonatal hepatitis is an umbrella term for several liver disorders that become apparent in newborns shortly after birth. Many cases of infant hepatitis are known to be the result of metabolism disorders, genetic factors or viral infections. However, in some cases of neonatal hepatitis the cause is unknown. This is called idiopathic hepatitis.
Numerous other conditions and substances can lead to hepatitis. These include:
- Certain medications, such as antibiotics or excessive paracetamol;
- Haemochromatosis, a condition that causes the body to absorb too much iron, and;
- Fatty liver, which is the fatty infiltration of the liver, due to excess fats and cholesterol in the body. Also known as non-alcoholic steatohepatitis (NASH).
Risk factors for hepatitis vary according to the type of hepatitis. The different hepatitis viruses are not related and do not share the same modes of transmission. The non-viral types of hepatitis, as noted above, arise from a variety of causes. Therefore, there is no single set of risk factors for contracting hepatitis.
Nevertheless, the risk of contracting hepatitis is higher for the following groups and practices:
The hepatitis B and hepatitis C viruses move from person to person via direct blood-to-blood contact. Blood transfusion recipients are at an increased risk of contracting these viruses from infected donors. Blood used for transfusion in Australia is carefully screened for these diseases.
Intravenous drug use
Sharing needles between injecting drug users is another major route for the blood-to-blood transfer of hepatitis B and C viruses.
Persons living in, or travelling to, countries where viral hepatitis is common are at risk of contracting the viruses. The main infection route is through contaminated food or water, where hepatitis A can be found.
Tattoos and body piercings
People who have had tattoos and body piercings done in an unsanitary way are at risk of blood-to-blood contact with hepatitis B and C carriers.
People who have unsafe sex - without the use of barriers such as condoms - with people who are carriers of hepatitis B and C viruses can catch the virus this way.
Excessive alcohol consumption
Drinking large amounts of alcohol can cause alcoholic hepatitis. Alcohol consumption can also worsen and complicate the symptoms of other types of hepatitis.
Signs and symptoms
Hepatitis infections can be divided into two categories: acute and chronic. The liver can sustain a fair amount of damage before it starts malfunctioning. As a result, in many conditions affecting the liver, the signs and symptoms are slow to appear. In some people symptoms do not appear at all, or are only mild. In other people, the acute phase will come in the weeks after contracting hepatitis and typically go away on its own after 4-6 weeks. In the months and years following, chronic hepatitis can appear.
The signs and symptoms of hepatitis are all the result of the inflamed liver's inability to carry out its normal functions of detoxifying the blood and helping digestion. Symptoms of hepatitis include:
Methods for diagnosis
Hepatitis is diagnosed through one or a series of blood tests. These tests can measure liver function and, in the case of viral hepatitis, identify the viruses in the blood, or antibodies that the body's immune system produces in response to the viruses.
Diagnosis of viral hepatitis
Hepatitis viruses can be hard to detect soon after infection. It may take several weeks or even months before the presence of the virus particles, or the body's immune reaction to them, can be reliably detected by blood tests.
Diagnosis of non-viral hepatitis
In non-viral hepatitis, the diagnosis usually relies on the patient's history, physical examination and blood tests that check the functioning of the liver. In some cases, a liver biopsy will be taken.
Types of treatment
Treatment of hepatitis often depends on the specific cause. In general, treatment focuses on managing the symptoms, supporting the body's immune system as it handles the infection, helping the body recover, and easing the burden on the liver as much as possible. Treatment measures can include:
- Good nutrition, with a preference for small, frequent meals;
- Drinking plenty of fluids, and;
- Avoiding alcohol.
Severe viral hepatitis treatments
The more serious kinds of viral hepatitis cases may be treated with antiviral medication, with varying success rates.
Non-severe viral hepatitis treatments
For the less aggressive cases of viral hepatitis, often no specific treatment is recommended.
Alcoholic hepatitis treatments
For alcoholic hepatitis, therapy usually focuses on supporting the liver and the body's recuperation by improving nutrition and avoiding alcohol.
Autoimmune hepatitis treatments
For autoimmune hepatitis, immunosuppressants are used to calm down the harmful immune reaction against the liver cells.
Ischaemic hepatitis treatments
Treatment of ischaemic hepatitis usually focuses on treating the root problem of the condition - the heart or circulatory problem that is reducing blood supply to the liver.
In some cases, where the liver has sustained considerable damage, complications can arise. These include:
Scarring of the liver, or cirrhosis, occurs when healthy liver cells are replaced by scar tissue. The liver cannot work properly, which can seriously affect a person's health.
Significant cirrhotic liver damage can lead to liver failure - a state where the liver cannot perform its functions. If that occurs, a liver transplant is required in order to avoid death.
Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, is a dangerous complication of liver cirrhosis. It is the leading cause of death in people with chronic hepatitis and the sixth most common and third-deadliest type of cancer in the world.
Viral hepatitis can be prevented by avoiding infection. The best way of avoiding infection with hepatitis B, D and C is to avoid contact with other people's blood, while the best way of avoiding infection with hepatitis A and hepatitis E is practising good hygiene and avoiding eating uncooked food, or food from dubious sources.
If a person is infected with hepatitis B or C, they can prevent transmitting the disease to others by:
- Avoiding donating blood or organs;
- Avoiding sharing items such as needles, razors, toothbrushes and nail scissors;
- Telling health professionals who treat them about their condition - particularly doctors, dentists and others who might come into contact with blood;
- Dressing wounds and disposing of any blood-stained items safely;
- Avoiding getting tattoos or body piercings;
- Practising safe sex, and;
- Encouraging close household contacts and sexual partners to be immunised against hepatitis B.
People infected with hepatitis A or E can prevent transmitting the disease to others by practising good hygiene measures.
Vaccines are available for protection against hepatitis A and hepatitis B viruses.
Reducing the chance of complications
You can lower your risk of severe complications by drinking less alcohol, eating a healthy diet low in fat to prevent obesity and diabetes, and not smoking tobacco and cannabis.