The liver is the largest solid organ and gland. It performs 500 critical functions including: digesting food and converting it into energy; fighting infections; storing iron and other essential vitamins; and cleaning the blood.
It's able to regenerate itself, but long-lasting damage and scar-tissue can lead to cirrhosis, where the liver is so scarred it no longer works properly, which can lead to liver failure.
The main causes of liver disease are obesity, an undiagnosed hepatitis infection and drinking too much alcohol.
Non-alcoholic fatty liver disease (NAFLD) occurs when too much fat builds up inside liver cells and is associated with being overweight. Over the last 20 years, NAFLD cases have doubled and it's now the most common cause of abnormal liver function tests in the UK, leading to an increased risk of heart attacks, stroke and diabetes.
Drinking too much alcohol can lead to alcohol-related liver disease (ARLD). The liver is able to breakdown the alcohol and remove it from the body, but is unable to regenerate itself.
Viral infections can also infect the liver, which can lead to inflammation. Hepatitis A, B and C are common types of liver infection. Other causes of liver disease include the inherited disorder hemochromatosis, where there's too much iron in the body and this can damage organs.
These conditions can lead the liver to become inflamed, and lead to scarring – a condition called fibrosis. Scar tissue develops around the liver, and if left untreated will result in cirrhosis. Cirrhosis and hepatitis B are leading risk factors for liver cancer.
There may not always be obvious signs of liver disease until the liver is damaged. Common symptoms include nausea, weight loss, weakness and fatigue, vomiting and yellowing of the skin (jaundice).
Cirrhosis may be the first sign of liver disease and symptoms include tenderness or pain around the liver, itchy skin, tendency to bruise or bleed more easily, hair loss, swelling in the feet, ankles and legs and a swollen abdomen.
Your doctor should look at your history and arrange for you to have blood tests, known as liver function tests. These can identify abnormal clotting that can be a sign of severe liver damage.
Imaging tests of the liver, such as an ultrasound scan, which uses high-frequency sound waves to create an image of the body; and a computerised tomography (CT) scan, which uses x-ray and a computer to create a detailed image, may show up scarring.
A liver biopsy, where a sample of liver cells is taken, and an endoscopy, which involves examining the oesophagus and stomach with a tiny fibre-optic camera, which can be swallowed, may also be carried out.
Who gets liver disease?
Liver disease can affect anyone and can be genetic or caused by a variety of factors, such as viruses, obesity, alcohol, autoimmune diseases and drugs and toxins.
Treatment depends on what type of liver disease you're diagnosed with.
If you have NAFLD, making lifestyle changes, such as losing weight by taking regular exercise and eating a healthy diet, not drinking alcohol and stopping smoking, is important and can also prevent it.
With ARLD, it's important to stop drinking alcohol. Your doctor may recommend you attend an alcohol recovery programme and follow a special diet to get all the nutrients you need as malnutrition is common.
Protecting yourself from further infection by having up-to-date vaccinations, such as the flu vaccine, pneumococcal infection and hepatitis A and B, is vital.
With viral hepatitis, treatment isn't always needed unless the condition becomes chronic and it's damaging your liver, when anti-viral medications may be recommended.
If you develop cirrhosis, you can treat underlying causes such as hepatitis C with anti-viral drugs. You can also ease your symptoms by using creams to reduce itching; taking diuretic tablets or eating a low-salt diet, which can help to reduce fluid in the body; and taking pills to reduce high blood pressure in the portal vein – the blood vessel that carries blood to the liver.
If your liver becomes too damaged and doesn't work anymore, you may need a liver transplant, where the diseased liver will be replaced with a healthy one.