The liver is an extremely important organ with a vast variety of bodily functions. In brief, it removes toxins that are fat soluble (water soluble toxins are excreted in the urine), regulates blood composition including glucose levels, and produces bile which is stored in the gall bladder and which is essential for digestion.
Hepatitis is a general term that implies inflammation of the liver, from the Greek hepar (liver) and itis (inflammation). Hepatitis can be caused by a wide variety of insults and is called acute when it lasts up to six months, or chronic when it persists for more than six months. Hepatitis may resolve spontaneously, or may cause progressive liver damage, leading to scarring of the liver with cirrhosis, and eventually, liver failure and possibly also liver cancer. Hepatitis may run a subclinical course, that is, when the affected individual does not feel unwell. When the individual is clinically affected, liver function is impaired, leading to malaise, jaundice, a tender liver etc.
The commonest hepatitis causing toxin is alcohol. Certain drugs may also cause hepatitis as well as some auto-immune diseases wherein the body’s immune system attacks parts of the body itself.However, the term “hepatitis” is most commonly used to refer to viral infections of the liver that cause liver inflammation. These are most commonly called hepatitis viruses.
The hepatitis virus that is most commonly known about by the general population is the hepatitis B virus. Transmission is through unscreened blood products and through intimate (e.g. sexual) contact, much like the HIV (Aids) virus. In this instance, hepatitis may be acute or chronic, with the latter leading to liver failure or hepatic cancer. Acute hepatitis B infection may also kill acutely due to rapid liver failure. It is estimated that approximately one-third of the world’s population (that is, over two billion people) have contracted this form of hepatitis, and that this has resulted in 350 million chronic carriers worldwide.
More than 95 per cent of infected individuals, if older children or adults, recover fully and become totally immune to reinfection with this virus. However, the younger the patient, the less likely the recovery. Only five per cent of newborn babies that acquire hepatitis B from their mother during the birth process will recover completely from the infection and only 70 per cent of children infected between the age of one to six will recover completely from the infection. Treatment is very limited and expensive, at the time of writing, and therefore prevention is crucial.
Hepatitis A causes an acute liver infection and is transmitted by the feco-oral route, that is by contaminated food water. This can easily occur if infected individuals do not observe proper hand hygiene after defecation. It is estimated that about 10 million people worldwide are infected with the hepatitis A virus and in countries with poor hygiene, almost all individuals contract the disease, usually in early childhood. Over 90 per cent of younger children do not show any signs of disease and recover fully with lifelong immunity to this virus. In developed countries, infection, when it occurs, usually takes place in adult life, during holidays to underdeveloped parts of the world. In these older individuals, infection is more likely to be severe.
Hepatitis A never causes chronic hepatitis or permanent liver damage but may rarely cause acute and life-threatening liver failure like hepatitis B.Hepatitis C is transmitted in the same way as hepatitis B (unscreened blood products, etc) and infection is often silent, with no symptoms at all. It is estimated that close to 200 million people are infected with hepatitis C worldwide. Like hepatitis B, this virus may cause chronic hepatitis with liver failure or liver cancer. And like hepatitis B, medical treatment is limited and expensive.
Next week we will deal with vaccines that are available for hepatitis.