What does the liver do?
The liver is the largest organ or gland in the body. Its many functions are essential to our wellbeing and healthy living. The liver:
- is important in the digestion of food, producing bile to help break down carbohydrates, protein and fats
- stores carbohydrates in a form that allows a quick release of energy when needed, which is why people with liver damage often report a lack of energy
- helps to keep the blood clean and healthy, disposing of defunct red blood cells and removes excess amino acids in the blood, breaking them down into ammonia and then urea
- controls the level of fats in the blood by making cholesterol
- makes plasma proteins, needed to help the blood to clot (coagulants), and also to keep the blood from thickening too much (anticoagulants)
- helps the body to destroy poisons such as alcohol, and to get rid of other unwanted substances
- makes and regulates many hormones, including sex hormones.
What are the causes of liver disease?
The liver can be damaged in a variety of ways:
- cells can become inflamed (such as in hepatitis)
- bile flow can be obstructed (such as in cholestasis)
cholesterol or triglycerides can accumulate (such as in steatosis)
- blood flow to the liver may be compromised
- liver tissue can be damaged by chemicals and minerals, or infiltrated by abnormal cells.
- alcohol abuse is the most common cause of liver disease in the UK today. Alcohol is a toxin and can cause severe inflammation of the liver, referred to as alcoholic hepatitis. In chronic alcohol abuse, fatty accumulation (steatosis) occurs in liver cells causing the cells to malfunction.
What are the most common types of liver disease?
When the liver’s functions become depleted, it becomes susceptible to a number of diseases and disorders. Many of these are accompanied by jaundice caused by increased levels of bilirubin – normally the liver removes bilirubin from the blood and excretes it through bile. Some of the most common types of disorders affecting the liver include:
Cirrhosis - a late-stage liver disease leading to scarring of the liver and loss of function causing the liver to fail.
Drug-induced liver disease - liver cells may become temporarily inflamed or permanently damaged by exposure to certain medications or drugs. Some require an overdose to cause liver injury while others may cause damage even when taken in the appropriately prescribed dosage.
Infectious hepatitis - The term "hepatitis" means inflammation of liver and the liver cells can become inflamed due to infection. The main types of Hepatitis viruses are:
- Hepatitis A - a viral infection caused primarily through the faecal-oral route when small amounts of infected faecal matter are inadvertently ingested. Hepatitis A causes an acute inflammation of the liver which generally resolves spontaneously. The Hepatitis A vaccine can prevent this infection.
- Hepatitis B - is spread by exposure to body fluids (needles from drug abusers, contaminated blood, and sexual contact) and can cause an acute infection, but can also progress to cause chronic inflammation (chronic hepatitis) that can lead to cirrhosis and liver cancer. The hepatitis B vaccine prevents this infection.
- Hepatitis C causes chronic hepatitis. An infected individual may not recall any acute illness. Hepatitis C is spread by exposure to body fluids (needles from drug abusers, contaminated blood, and sexual contact). Chronic hepatitis C may lead to cirrhosis and liver cancer. At present, there is no vaccine against this virus.
- Hepatitis D is a virus that requires concomitant infection with hepatitis B to survive, and is spread via body fluid exposure (needles from drug abusers, contaminated blood, and sexual contact).
- Hepatitis E is a virus that is spread via contaminated food and water exposure.
We work closely with our infectious diseases clinicians holding a joint clinic every Thursday for patients diagnosed with all types of Hepatitis. We are one of the very few providers in the North East able to offer patients with Hepatitis B and C interferon and ribavirin. If you do need this treatment you will see one of our Viral Hepatitis Nurse Specialists who run regular nurse led clinics where they can provide the appropriate treatment either by injection or in tablet form.
We know that being diagnosed with Hepatitis B or C can be very distressing and our nurse specialists can provide you with advice and support to help you manage your condition, and put you in touch with local support agencies.
Other viruses can also cause liver inflammation or hepatitis as part of the cluster of symptoms. Viral infections with infectious mononucleosis (Epstein Barr virus), adenovirus, and cytomegalovirus can inflame the liver. Non-viral infections such as toxoplasmosis and Rocky Mountain spotted fever are less common causes.
Non-Alcoholic fatty liver disease - Accumulation of fat within the liver can cause gradual decrease in liver function. Also known as nonalcoholic steatohepatitis, fatty liver disease, or NASH.
Haemochromatosis - Haemochromatosis (iron overload) is a metabolic disorder that leads to abnormally elevated iron stores in the body. The excess iron may be found in the tissues of the liver, pancreas, and heart and can lead to inflammation, cirrhosis, liver cancer, and liver failure. Haemachromatosis is an inherited disease.
Wilson's Disease - another inherited disease that affects the body's ability to metabolize copper. Wilson's disease may lead to cirrhosis and liver failure.
Gilbert's Disease - an abnormality in bilirubin metabolism in the liver. It is a common disease that affects up to 7% of the North American population. There are no symptoms and it is usually diagnosed incidentally when an elevated bilirubin level is found on routine blood tests. Gilbert's disease is a benign condition and no treatment is necessary.
Cancers - Primary cancers of the liver arise from liver structures and cells. Two examples include hepatocellular carcinoma and cholangiocarcinoma. Metastatic cancer (secondary cancer of the liver) begins in another organ and spreads to the liver, usually through the blood stream. Common cancers that spread to the liver begin in the lung, breast, large intestine, stomach, and pancreas. Leukaemia and Hodgkin's lymphoma may also involve the liver.
Blood flow abnormalities - Budd Chiari syndrome is a disease in which blood clots form in the hepatic vein and prevent blood from leaving the liver. This can increase portal vein pressure and lead to cirrhosis and liver failure. Causes of Budd Chiari syndrome include polycythemia (elevated red blood cell count), inflammatory bowel diseases, sickle cell disease, and pregnancy. Congestive heart failure, where fluid and blood backs up in the large veins of the body can cause liver swelling and inflammation.
Bile flow abnormalities - normally, bile flows from the liver into the gallbladder and ultimately into the intestine to help with the digestion of food. If bile flow is obstructed, it can cause inflammation within the liver. Most commonly, gallstones can cause an obstruction of the ducts that drains bile from the liver. Abnormalities of the opening of the bile duct into the intestine (sphincter of Oddi) can lead to abnormalities of bile flow. The sphincter of Oddi acts as a "valve" that allows bile to flow from the common bile duct into the intestine. Primary biliary cirrhosis and primary sclerosing cholangitis can lead to progressive scarring of the bile ducts, causing them to become narrow, which results in reduced bile flow through the liver. Eventually, damage and scarring of the liver architecture causes liver failure to develop.
Other diseases and conditions
Conditions such as portal hypertension (increased blood pressure within the portal vein), abnormal blood clotting, and hepatic encephalopathy (abnormal brain function due to elevated levels of ammonia in the blood stream) can also affect the liver.