The LIVER and LIVER DISEASE*
The liver is a vital organ present in vertebrates and some other animals. It is the largest internal organ in the human body and weighs 1.5kg in the average adult. It is the second largest organ of the body, the skin being the largest.
Medical terms related to the liver often start with hepato- or hepatic from the Greek word for liver, hepar.
Where is the Liver?
The liver is situated in the upper right side of the abdomen immediately below the diaphragm (a set of muscles below the rib cage and lungs that helps with breathing). Blood from the digestive system must first filter through the liver before it travels anywhere else in the body. This is the 'portal venous system'.
Functions of the Liver
In general, the liver clears toxins from the body, processes food nutrients and is involved in regulating body metabolism. Without your liver, you are unable to digest food and absorb nutrients, get rid of toxic substances from your body, or stay alive.
Some of the many functions of the liver include:
- Production of bile. This is an alkaline compound, bitter tasting, dark green to yellowish in colour, which is stored in the gall bladder and released into the small intestine, where it is used to help break down dietary fats, which it does via emulsification of them. The fat soluble vitamins A, D, E and K need bile to be absorbed by the body. Bile contains mostly cholesterol, bile acids (also called bile salts), and bilirubin (a breakdown product of red blood cell). It also contains water, potassium, sodium, copper and other metals.
- Once food, medicines, liquids etc that have been consumed are digested in the small intestine and absorbed through the walls of the small intestine, these products of digestion (nutrients and other molecules) are then transferred to the liver via the portal blood for further processing. The liver's highly specialised tissues regulate a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex molecules, many of which are necessary for normal vital functions.
- The liver not only receives glucose from the small intestine but also converts carbohydrates into glucose for instantly available energy. Excess glucose is converted into its storable form, glycogen. When the blood glucose (sugar) levels drop, glycogen is converted back to glucose and released into the blood.
- Amino acids, the breakdown of digested protein, go to the liver for the production of body proteins including hormones.
- The liver changes ammonia (a toxic by-product of protein metabolism) into urea, which is transferred to the kidney and removed from the body by excretion in the urine.
- Drugs, including alcohol, are filtered through the liver and neutralised or converted into other forms by special enzymes. Virtually all of the drugs that we take (medicinal, recreational, chemotherapy etc.) are processed, purified and refined in the liver, in preparation for elimination from the body. The liver is the body's 'detoxifier'.
- The liver stores iron, vitamin B12 and copper.
- The liver makes cholesterol and other fats that are needed by the body. Cholesterol is an important ingredient in many cells and hormones in the body.
- The liver is the only organ in the body that is capable of regenerating if parts of it are removed (eg via surgery) or become diseased. However, even a resilient organ such as the liver cannot withstand long-term pressures such as consuming too much alcohol or other substances that may be toxic or harmful. This can lead to permanent damage in the form of cirrhosis or liver cancer.
Symptoms of Liver Disease
The symptoms of liver disease depend on the disorder or disease process, but can include:
- Jaundice (the skin or whites of the eye turn yellow due to increased bile levels and the deposit of bilirubin)
- Itching (the most common complaint by people who have liver failure, due to the deposits of bilirubin in the skin. The itch cannot be relieved by drugs)
- Pale stools (absence of the pigment stercobilin derived from bilirubin in the bile)
- Dark urine (bilirubin being excreted via the kidney)
- Appetite loss
- Weight loss
- General malaise and excessive fatigue
- Bloated abdomen
- Tenderness in the right upper side of the abdomen
- Bruising (the liver makes substances which help prevent bleeding)
- Haematemesis (vomiting blood)
- Melaena (black tarry stools due to altered blood)
- Changes in mental state - insomnia, confusion, drowsiness.
Causes of Liver Disease
There is a range of causes which include:
- Non-alcoholic fatty liver disease ('fatty liver').
- Hepatitis. This is inflammation of the liver and is associated with swelling and pain. Hepatitis may be caused by infection, viruses, chemicals, alcohol, and drug use (pharmaceutical and recreational). The various forms of viral hepatitis include hepatitis A, B, C, D, and E. 'Chronic hepatitis' means on-going inflammation of the liver irrespective of the underlying cause.
- Alcohol-related liver disease.
- Toxic effects of medications and drugs.
- Congenital or inherited abnormalities of the liver involving accumulation of iron (haemochromatosis - see my April 2008 newsletter Iron) and copper (Wilson disease - see my June 2013 newsletter Wilson Disease) in the body.
- Gilbert's syndrome or idiopathic hyperbilirubinaemia. This is a genetic abnormality where the bilirubin levels are elevated without other abnormality in the liver. There may be some mild symptoms such as chronic fatigue. It requires no treatment and does not shorten life.
- Damage or obstruction to the biliary system within or outside the liver. For example: primary sclerosing cholangitis (inflammation of the bile ducts) and gall stones obstructing the outflow of bile from the liver.
Changes that occur in the Liver in Liver Disease
- Fatty liver. This is the most common of the alcohol-induced liver disorders. Fat accumulates inside the liver cells, causing them to enlarge and become damaged and can lead to cirrhosis. Similar changes are also seen in people who do not drink excessive amounts of alcohol but are overweight, obese or have diabetes.
- Cirrhosis. This has many causes but is commonly due to hepatitis infection or excessive alcohol intake. The cells of the liver are progressively replaced by scar tissue, which seriously impairs liver function and can result in death.
- Hepatitis. (See comments above)
- Cancer. Primary cancers can arise in the liver, most often from chronic hepatitis with cirrhosis. Secondary cancers or metastatic cancer arise from stray cells from a tumour elsewhere in the body.
Complications of Liver Disease
Without treatment, a person with liver disease is susceptible to a wide range of complications including:
- Ascites (fluid retention in the abdominal cavity due to a build-up of sodium)
- Oedema (swelling in the feet, legs and back, again due to a build-up of sodium)
- Hepatic encephalopathy (due to build-up of toxins especially ammonia which affect brain function and can lead to coma)
- Liver failure (the liver cells are destroyed more rapidly than they can be replaced until the liver can no longer function adequately)
- Gastrointestinal bleeding (as a result of oesophageal varices which form when the blood flow through the liver is obstructed by cirrhosis. These enlarged veins may rupture and bleed profusely, giving a medical emergency).
Diagnosis of Liver Disease
Liver disease is diagnosed by one or more of the following tests:
- Clinical history which must enquire about medications, lifestyle factors such as diet and alcohol consumption, blood transfusions, exposure to hepatitis viral infections, and family history of liver disease.
- Physical examination - the liver may be enlarged.
- Blood tests. These are called 'liver function tests'. These check the levels of liver enzymes, bilirubin and various proteins produced by the liver.
- Ultrasound scan of the abdomen.
- Other scans, such as computerised tomography (CT scan) and magnetic resonance imaging (MRI).
- Biopsy, where a small piece of liver tissue is obtained and examined under the microscope. This is most often done using a long needle inserted through the skin to extract a tissue sample (needle biopsy).
Treatment of Liver Disease
Treatment of course depends on the cause. The following should always be carried out:
- No alcohol
- No drugs that may damage the liver
- A well-balanced, nutritious diet.
Other possible treatments include:
- Medications such as antiviral drugs
- Specific medications for Wilson disease
- Removal of blood to reduce iron levels in the body in haemochromatosis
- Surgery, chemotherapy and radiotherapy for liver cancer
- Liver transplant when severe liver failure is present.
There are certain herbal supplements used as alternate medicine treatments, for example Milk thistle or Silybum, Phyllanthus and liquorice root extract. Full details of these and others will be the topic of another Collison Newsletter.
Some facts on Liver Disease
- Six million Australians are, or have been, affected by liver, bile duct or gall bladder disease.
- Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease in Australia, with an estimated 5.5 million (2012) Australians affected, including 40% of all adults aged 50 years and above. NAFLD, when severe, can progress to cirrhosis and liver failure, with 2,264 deaths in 2012.
- Alcoholic related liver disease (ALD) is undetected during the early stages of the disease. It is estimated that there were 6,200 cases of ALD in Australia in 2012. Statistics show that 751 ALD related deaths (558 males and 193 females) occurred in Australia in 2010.
- Fatty liver, an obesity-related liver condition, may affect many of the 30% of adults in Australia who are overweight.
- Liver cancer is the most rapidly increasing cancer worldwide.
- Hepatitis B and C significantly increase the risk of liver cancer.
- Almost 3,000 Australian adults and children have undergone successful liver transplantation and require ongoing care.
- Many forms of liver disease are preventable and many more, if detected early, can be treated effectively.
*Copyright 2014: The Huntly Centre.
Disclaimer: All material in the huntlycentre.com.au website is provided for informational or educational purposes only. Consult a health professional regarding the applicability of any opinions or recommendations expressed herein, with respect to your symptoms or medical condition.Back to the list Print friendly version