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Written by Dr John ET Pillinger, GP
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What is jaundice?
Jaundice means the yellow appearance of the skin and whites of
the eyes that occurs when the blood contains an excess of the pigment called
bilirubin.
Bilirubin is a natural product arising from the normal breakdown
of red blood cells in the body and is excreted in the bile, through the actions
of the liver.
Although jaundice is most often the result of a disorder
affecting the liver it can be caused by a variety of other conditions affecting
for example the blood or spleen. It should be thoroughly investigated so that
the underlying cause can be identified and treated.
How does a person get jaundice?
The red blood cells in our circulation carry oxygen to all
parts of the body and have a life span of about 120 days. At the end of their
life they are broken down and removed from the circulation by special cells
called phagocytes, which are found within the bone marrow, spleen and liver.
New red cells are of course continually manufactured and this
also takes place within the bone marrow.
Following breakdown of the red cells some of their component
parts such as amino acids and iron can be re-used by the body. Other components
such as bilirubin need to be removed.
Knowing how this removal pathway works is the key to
understanding how jaundice occurs.
Most waste products of the body are excreted in the urine via
the kidneys but the liver and bile system is the other main physical route out
of the body for these substances.
By 'waste products' we mean the many compounds that
arise in the course of the body's metabolism but almost all forms of drugs
must also be eliminated either via the urine or bile routes.
In the case of bilirubin released from old red cells, it passes
through the bloodstream to the liver, where the liver cells process it.
These cells carry out many complex chemical functions and also
produce the liquid bile, which is the 'vehicle' by which the cells
discharge their output to the bile duct system. This is a branching network of
tiny tubes throughout the liver, which merge in the same way as the branches of
a tree.
Ultimately a single main bile duct comes out of the liver and
joins the first part of the small intestine (duodenum). Bile (and therefore
bilirubin) then passes out through the small and large intestines and is
excreted in the stool (faeces).
Bile is green in colour, but bacteria in the large bowel act to
change the bilirubin to substances that are brown, which gives stool its
characteristic colour.
Some of the bilirubin is reabsorbed back into the body through
the bowel wall, eventually appearing in the urine as a substance called
urobilinogen (although the typical yellow/orange colour of urine is in fact due
a different pigment called urochrome).
Therefore, any failure of the bilirubin removal pathway will
lead to a build-up of bilirubin in the blood. When this happens the
individual's skin turns yellow, causing jaundice.
What conditions can be associated with jaundice?
An excessive breakdown of red blood cells
The balance between manufacture and breakdown of red cells is
normally precisely balanced and equal but there are several conditions in which
the rate of breakdown increases. If the amount of bilirubin thus released
exceeds the liver's capacity to remove it, then jaundice will
develop.
The medical term for excessive red cell breakdown is
'haemolysis', and within the developed world it is a fairly rare
condition. Malaria is however a major cause in tropical climates as the malaria
parasites live within the red cells and shorten their life.
Similarly the condition in which a foetus develops haemolysis
due to incompatibility of its Rhesus blood group with that of its mother is now
rarely seen in the UK where we routinely check for 'Rhesus
antibodies' in the mother's blood. In parts of the world where
antenatal care is not as good haemolytic disease of the newborn is much more
common.
A temporary jaundice of newborn babies is however quite
common, due to the relative immaturity of the baby's liver cells and the
higher than normal rate of cell breakdown that occurs in the first few weeks of
life. It improves rapidly without treatment although when too high it can be
speeded up by exposing the baby to ultraviolet light. Jaundice of the newborn
is commoner in premature babies as their liver is even more immature than a
baby born at term.
Autoimmune haemolytic anaemia is a rare disease in which the
body's immune system seems to attack the red cells. It usually affects
adults. Haemolysis can also be a side effect of some drugs, eg
dapsone.
Impairment of liver cell function
The commonest cause is a viral infection of the liver cells
(hepatitis). Many
different types of infection including glandular fever (mononucleosis) can also
be responsible for this.
Alcohol abuse and subsequent scarring of the liver
(cirrhosis) can cause significant cell damage leading to jaundice. Other less
common conditions causing liver cell damage include
haemochromatosis,
alpha-1 antitrypsin
deficiency and
primary biliary
cirrhosis. Tumours of the liver - either primary liver cancers (arising
from the liver tissue itself) or more commonly, the secondary spread of a
tumour from elsewhere in the body into the liver can lead to cell failure and
jaundice.
Blockage of the bile ducts
This can occur as a result of abnormality inside or outside
the ducts. The commonest example of an internal blockage is a gallstone.
Tumours of the bile duct are rare but if large enough, or situated just where
the bile duct meets the duodenum, then they can block the flow of bile. At this
junction point, known as the ampulla of Vater, the tube from the pancreas gland
also joins to the duodenum. Cancer of the pancreas tends to arise in the part
of the pancreas nearest to the ampulla of Vater, so is another potential cause
of 'obstructive' jaundice.
Any external organ or mass lying nearby that becomes large
enough to press on the bile duct could be responsible. Examples include swollen
internal lymph glands, a cyst (perhaps of the pancreas) or scar tissue
following a previous infection or surgery.
What are the symptoms?
The symptoms, other than that of the jaundice itself, will
relate to the underlying cause. For example someone with haemolysis might also
be anaemic and tired. If a gallstone were responsible there would probably have
been a preceding history of pain in the abdomen. A cancer might be accompanied
by weight loss, and so on.
When jaundice is due to obstruction of the bile duct the person
will often notice that their urine becomes dark and stools become pale, as the
excess bilirubin 'spills over' into the urine and no longer colours
the stool. Obstructive jaundice is also often accompanied by intense itching.
How is jaundice diagnosed?
The diagnosis is made by recognition of the patient's
appearance and accompanying symptoms. A blood test will confirm the raised
bilirubin level and other tests such as those for hepatitis and haemolysis are
also done on the blood.
Ultrasound is a good
way to inspect the liver and bile ducts for signs of obstruction, and often can
give useful information on the pancreas gland.
CT scanning also
helps diagnose obstructive jaundice accurately.
What can your doctor do?
If you or one of your friends or relatives suspect that you may
have jaundice, it is essential that you arrange to see your doctor in order
that the underlying cause is identified and any possible treatment initiated as
soon as possible.
Treatment will depend upon the diagnosis behind the symptom of
jaundice. For example, if the problem is one of gallstones, then removal of the
gallbladder may be required.
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Last updated 04.08.2005
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