The condition is due to the presence of a high level of a pigment called bilirubin in the blood - and then the skin. Depending on the reason for the jaundice it may be accompanied by a variety of other symptoms including itching, malaise, loss of appetite, fever and abdominal pain and these symptoms, together with blood tests, normally provide the clues to the cause.
Physiology of Jaundice
All tissues of the body are turned over – continually broken down and replaced and blood is no exception. Red cells are constantly being produced by the bone marrow and older worn out cells are broken down, a process known as haemolysis. Bilirubin is a waste product of this being derived from haemoglobin, the red component of blood and it's removal from the blood is dealt with by the liver.
The cells of the liver take in bilirubin, detoxify it and use it to manufacture bile which is then secreted into small channels which eventually pour the bile into the gall bladder. From here bile is excreted through the bile duct into the intestine where it aids digestion of fats. Some bilirubin is excreted in faeces and some is reabsorbed, enters the blood stream and is passed in the urine.
Three Causes of Jaundice
It follows from the way bilirubin is produced and dealt with by the liver that three kinds of physiological malfunction will produce jaundice and sometimes a combination of these occurs.
If red cell breakdown occurs very rapidly or in excessive numbers the liver's detoxifying processes will be overwhelmed. This type of jaundice is called haemolytic jaundice.
When the liver cells themselves are faulty or damaged, and the reasons for this will be given later, the detoxification processes becomes inefficient. Jaundice occurring for this reason is termed hepato-cellular jaundice.
The third scenario which leads to jaundice is when the channels carrying bile to the gall bladder or from the gall bladder to the intestine are blocked in some way, leading to backing up of the system. This is known as obstructive jaundice.
Haemolytic Jaundice
A variety of clinical condition can bring about an excessively rapid turnover of red blood cells. Some of the most common are listed below.
- Hereditary: a few inherited diseases may cause red cell destruction and jaundice; examples are sickle cell disease, thalassaemia and G6PD deficiency (an enzyme deficiency in red cells).
- Immune response: autoimmune haemolytic anaemia, blood transfusion mismatch, rhesus incompatibility.
- Malignancy; leukaemia.
- Drugs: these can cause haemolysis and jaundice either by directly damaging the red cells or by provoking an immune reaction; for example, methyl dopa.
Hepato-cellular Jaundice
Any agent that has the capacity to damage liver cells can cause jaundice. The usual agents are outlined below.
- Viruses: by far for the most common, viruses include the hepatitis group, cytomegalovirus, the infectious mononucleosis virus.
- Drugs: numerous drugs have the potential for overloading or causing cell damage since most drugs are metabolised by the liver.
- Chemicals: again many chemical agents can damage the liver some, such as carbon tetrachloride, will do so in small quantities, alcohol requires larger doses.
Obstructive Jaundice
The obstruction can occur at several places in and just outside the liver. Damage to the liver cells in hepato-cellular jaundice can cause blockage to the small channels which carry bile, in which case the picture becomes confused with an obstructive jaundice.
- Pregnancy: rarely the hormonal changes in pregnancy can give rise to jaundice. Quite how is poorly understood.
- Cell damage: causes include alcoholic cirrhosis and viral hepatitis.
- Malignancy: tumours which block the channels in the liver or to and from the gall bladder, examples are pancreatic cancer, lymphoma.
- Pancreatitis: the pancreas and gall bladder share a common duct so inflammation and swelling of the pancreas can impede the flow of bile into the intestine.
- Gall stones: if these are sufficiently large or cause inflammation.
This article is for information only. If you have any health concerns you should consult your doctor.
Sources:
Human Physiology: The Basis of Medicineby Pockock and Richards Pub OUP 1999
Medicine Eds. Souhami and Moxham. Pub. Churchill Livingstone 2002
John Richard Roberts - I am a practicing osteopath and acupuncturist living and working in the UK. I hold a Master's degree in Clinical Neuroscience. I have ...
