Canadian Liver Foundation | Liver Disease
http://www.liver.ca/Liver_Disease/Default.aspx

Liver Disease

Although liver disease is stereotypically linked to alcohol or drugs, the truth is that there are over 100 known forms of liver disease caused by a variety of factors and affecting everyone from infants to older adults. For further information on specific forms of children’s liver disease, please click here. For information on all other forms of liver disease, please click here.

Cirrhosis is often considered to be a form of liver disease and may be the only liver-related condition that many people have heard of. In fact, cirrhosis is a condition that results from permanent damage or scarring of the liver. It is the end stage of many different forms of liver disease and is known to cause a number of other health problems, including variceal bleeding, ascites and hepatic encephalopathy.

Many types of liver disease still have unknown causes but the most frequent liver diseases are generally caused by one of the following factors:

• Viral hepatitis
  Caused by viruses that attack the liver, viral hepatitis comes in many forms. The most common forms world-wide are hepatitis A, B and C. Although hepatitis A and B can be prevented by vaccine, there is no vaccine for hepatitis C. In Canada, hepatitis C is the leading cause of liver transplants.
  
  
• Obesity
  The leading cause of liver disease in Canada is fatty liver disease linked to obesity.
  
  
• Alcohol
  Factors such as gender, age, nationality, weight and health can affect how a person’s liver metabolizes alcohol. When the liver has too much alcohol to handle, normal liver function may be interrupted leading to a chemical imbalance. If the liver is required to detoxify alcohol continuously, liver cells may be destroyed or altered resulting in fat deposits (fatty liver) and more seriously, either inflammation (alcoholic hepatitis) and/or permanent scarring (cirrhosis). Liver cancer can also result from alcohol induced liver disease.
  
  
• Genetics
  Several forms of liver disease are caused or thought to be caused, by defective genes. These forms of liver disease may be diagnosed in infancy or may not show up until later in life. Examples include hemochromatosis, Wilson disease, tyrosinemia, alpha 1 antitrypsin deficiency and Glycogen Storage disease.
  
  
• Autoimmune disorders
  Sometimes a body’s immune system may begin to attack the liver or bile ducts causing inflammation and scarring which leads to a progressive form of liver disease. Examples of liver diseases believed to be caused by the immune system are primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis.
  
  
• Drugs and toxins
  The liver is responsible for processing most of the chemicals and medications that enter your body – this leaves it vulnerable to acute or chronic liver disease caused by chemicals. In some cases, this is a predictable consequence of overexposure or over-consumption of certain chemicals such as acetaminophen or industrial toxins like polyvinyl chloride or carbon tetrachloride. In other cases, chemicals can cause an unpredictable reaction.
  
  
• Cancer
  Although primary liver cancer is relatively uncommon, many other forms of cancer often metastasize in the liver. Because the liver filters a high volume of blood which may be carrying cancer cells, it is susceptible to developing a form of secondary cancer. If cancer originates in the liver, it is often caused by hepatitis B, hepatitis C or it can develop in cases of advanced liver disease when cirrhosis is present.