Sudden, short-term inflammation of the liver due to a variety of causes
- Lifestyle as a risk factor depends on the cause
- Age, gender, and genetics are not significant factors
Short-term inflammation of the liver is known as acute hepatitis. The condition has various causes and has a sudden onset. Most people with acute hepatitis recover within a month or two, but in some cases inflammation of the liver persists for many months or even years (see Chronic hepatitis) or progresses to liver failure.
What are the causes?
Worldwide, the most common cause of acute hepatitis is infection with any one of the several types of hepatitis viruses. Until the late 1980s, there were only two known hepatitis viruses, hepatitis A and B. Additional hepatitis viruses have now been identified, including hepatitis C, D, and E. Other hepatitis viruses are almost certainly yet to be discovered. The known viruses can all cause acute hepatitis, and they have many features in common, although the way in which they are transmitted and their longterm effects may differ. Infections with some types of bacteria, other nonhepatitis viruses, and some parasites can also lead to acute hepatitis. In addition, the condition may be caused by noninfectious agents, such as some drugs and toxins, including alcohol (see Alcohol-related liver disease).
Hepatitis A virus
The hepatitis A virus is common in southern and eastern Europe and some parts of Africa and Asia, but it is much less common in the UK. However, many cases are not reported because the virus often produces no symptoms or symptoms are so mild that the infection passes unrecognized. The virus can be detected in the urine and faeces of infected people, and it can be transmitted to other people in contaminated food or water.
Hepatitis B virus
Worldwide, it is estimated that 400 million people are infected with the hepatitis B virus. In the UK, about 1 in 1,000 people is infected with the virus, and most of them are in high-risk groups, such as immigrants from countries in which there is a high prevalence of the infection, people who have been exposed to unscreened blood products, or intravenous drug users who have shared contaminated needles. The virus is spread by contact with an infected person’s body fluids. Therefore it can be spread by sexual intercourse, for example, as well as by contaminated needles. Screening of blood products for hepatitis B and C was introduced in the UK in 1991 and so such products no longer pose the threat of infection. In developing countries, hepatitis B infection is most commonly transmitted from mother to baby at birth. Before blood banks routinely screened blood for the hepatitis B virus, as they do now, blood transfusions were a source of infection, and a number of people with haemophilia (see Haemophilia and Christmas disease) contracted hepatitis.
Hepatitis C virus
An estimated 210 million people worldwide are infected with the hepatitis C virus. There is no accurate information on the number of people infected in the UK but the infection seems to be mainly in those who have been exposed to unscreened blood products in the past (in the UK, blood has been routinely screened for hepatitis B and C since 1991) or who have shared contaminated needles. There is also a small risk of mothers passing on the infection to their babies, usually at the time of birth. Sexual transmission between heterosexual partners is possible but uncommon, and there is concern about the possibility of sexual transmission between men who have sex with other men.
Hepatitis D and E viruses
Infection with hepatitis D occurs only in people who already have hepatitis B infection. It is spread by contact with infected body fluids. The hepatitis E virus is a rare cause of hepatitis in the developed world. The virus is excreted in the faeces of infected people and is spread in much the same way as the hepatitis A virus.
Other infectious causes
Acute hepatitis may also be caused by other viral infections, such as cytomegalovirus (see Cytomegalovirus infection) and the Epstein–Barr virus, the cause of infectious mononucleosis. Some bacterial infections, such as leptospirosis and typhoid, can cause acute hepatitis. Parasitic infections that may lead to acute hepatitis include infection with plasmodium organisms, the cause of malaria.
In developed countries, excessive alcohol intake is one of the most common causes of acute hepatitis. The disease can also be caused by other toxins, such as those found in poisonous fungi. Certain drugs, such as the anaesthetic gas halothane, some anticonvulsants, and an overdose of paracetamol (see Painkillers), may cause acute hepatitis. Occasionally, the condition occurs in pregnancy, although the cause is not fully understood.
What are the symptoms?
Some people infected with a hepatitis virus have no symptoms or symptoms are so mild that they are not recognized. In other cases, the disorder may be life-threatening. If hepatitis is due to a viral infection, the time from infection to the appearance of symptoms can vary from up to 6 weeks for hepatitis A to 6 months for hepatitis B. Some people who have no symptoms may become carriers of the virus. If symptoms do develop, they may initially include:
Tiredness and a feeling of ill health.
Nausea and vomiting.
Discomfort in the upper right side of the abdomen.
In some cases, several days after the initial symptoms develop, the whites of the eyes and the skin take on a yellow tinge, a condition known as jaundice. Often, the initial symptoms improve once jaundice appears. At this time, the faeces may become paler than usual, and widespread itching may be present. Acute hepatitis caused by the hepatitis B virus may also cause joint pains.
Severe acute hepatitis may result in liver failure, causing mental confusion, seizures, and sometimes coma. Liver failure is relatively common following an overdose with the painkiller paracetamol but is less common with some types of hepatitis, such as those due to the hepatitis A virus.
How is it diagnosed?
If your doctor suspects that you have hepatitis, he or she may arrange for you to have blood tests to evaluate your liver function and to look for possible causes of your symptoms. Blood tests will probably be repeated in order to help monitor your recovery. If the diagnosis is unclear, you may undergo ultrasound scanning and may need to have a liver biopsy, in which a small piece of liver is removed and examined under a microscope.
What is the treatment?
There is no specific treatment for most cases of acute hepatitis, and people are usually advised to rest. Consult your doctor before taking any medicines, such as painkillers, because there is a risk of side effects. If you have viral hepatitis, you will need to take precautions to prevent the spread of the disease, including practising safe sex.
You should avoid drinking alcohol during the illness and for a minimum of 3 months after you have recovered. However, if the cause was alcohol-related, you will be advised to give up drinking alcohol permanently.
What is the prognosis?
Most people with acute hepatitis feel better after 4–6 weeks and recover by 3 months. However, ongoing (chronic) infection occurs in about 60–80 per cent of those infected with hepatitis C and about 5 per cent of those infected with hepatitis B or hepatitis B and D. People with acute hepatitis caused by an infection other than the hepatitis viruses usually recover completely once the infection has cleared up. Recovery from acute hepatitis caused by excessive alcohol consumption, drugs, or other toxins depends on the extent of the resulting liver damage. The substance that caused acute hepatitis must be avoided in the future.
In the rare cases in which hepatitis progresses to severe liver failure, a liver transplant may be necessary.
Can it be prevented?
Infection with hepatitis A and E may be prevented by maintaining good personal hygiene, such as always washing your hands thoroughly before handling food. The risk of infection with hepatitis B, C, and D can be reduced by practising safe sex and by not sharing needles or other objects that might be contaminated with infected body fluids. Those who have recovered from acute hepatitis A or B usually develop lifelong immunity to the respective viruses. However, there are several different strains of the hepatitis C virus so further infections are possible.
Immunizations that protect people against the hepatitis A and B viruses are given to those at particular risk of contracting the infection, such as travellers (see Travel immunizations).
In order to avoid the transmission of hepatitis through blood transfusions, blood banks routinely screen all blood for the presence of the hepatitis B and hepatitis C viruses.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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