What is bilirubin?
Red blood cells have a lifespan of about 115 days, after which they are broken down by macrophages (a type of white blood cells). Red blood cells contain haemoglobin which transports oxygen and carbon dioxide around in the body. During the breakdown of the red blood cell, haemoglobin will also be broken down, and during this process bilirubin is produced. Bilirubin is thus a decomposed product, and it stays in the blood until being absorbed in the cells of the liver and excreted with the bile.
Bilirubin is a fat soluble yellow-orange colouring. Increased amounts of bilirubin will cause it to pass from the bloodstream and out into the skin where the skin is dyed yellow. The bilirubin which floats freely in the blood is called unconjugated bilirubin. When it arrives to the liver, it becomes conjugated and thereby more water soluble, after which it is excreted with the bile to the small intestine. In the small intestine, some of it is converted to stercobilin, and this is what gives the stools a dark brown colour, while the other part is reabsorbed into the bloodstream and excreted with the urine where it is called ‘urobilin’, which gives the urine its yellow colour. If there is no stercobilin in the stool, it becomes putty-coloured, and without urobilin the urine turns dark.
Causes of jaundice
Jaundice is therefore a condition caused by increased levels of bilirubin. This can be a result of several different conditions. These conditions can either increase the production or reduce the excretion of bilirubin. It is especially diseases in the liver and bile ducts that cause the yellowing of the skin.
- Hepatocellular jaundice: if the liver loses its ability to conjugate or transport bilirubin to the bile ducts, bilirubin will accumulate in the blood and excrete with the urine. Part of this is caused by hepatitis, cirrhosis, liver cancer or an inherent disease called ‘Gilbert’s syndrome’.
- Obstructive jaundice: A closed bile duct also prevents the body from removing bilirubin, and the obstruction can be due to gallstones or inflammation of the bile ducts.
- Haemolytic jaundice: A condition called haemolytic anaemia. It can be due to a malaria infection, autoimmune diseases or drug poisoning.
Therefore, jaundice is an indication of a disease that should be taken seriously.
When should an adult with jaundice consult the GP?
If you as an adult experience jaundice, it is recommended that you consult your GP as quickly as possible as the underlying cause can be dangerous. Jaundice should especially be considered a warning if it is related to symptoms such as:
- Severe pain and soreness in the stomach
- Bloody stools or vomit
- Bleeding tendency
- Fever
- Nausea, agitation, fury or confusion
Jaundice in new-borns
New-borns have a relatively high number of red blood cells due to the low oxygen level in the womb of the mother. When the child is born, it will begin breathing through the lungs, raising the oxygen level. At this point, the new-born no longer requires that many red blood cells, which is why some of these cells will break down causing the amount of bilirubin to increase. Therefore, it is normal for a new-born to be a little yellowish in colour. In the majority of new-borns, the condition is fairly harmless, but all children with an indication of jaundice will be observed and have their bilirubin-levels in the blood measured as too high levels can damage the brain.
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