Introduction to liver disease

It receives blood from two sources:

• From the heart (via the hepatic artery)
• From the intestine (via the portal vein)

Blood from the liver goes back to the heart through the hepatic vein. 

The liver processes and stores nutrients from the blood to allow the body to use them. The blood entering the liver from the intestine contains fats, carbohydrates, vitamins and other nutrients.

Carbohydrates are broken down into sugars which provide energy. Excess sugars are stored in the liver as glycogen, for release when needed.

The liver produces lots of different substances that the body needs including:

• Blood plasma proteins such as albumin – albumin controls how much fluid is in each part of the body
• Clotting factors which help to stop bleeding
• Cholesterol
• Vitamin D
• Immune factors which help to fight infection
• Some hormones
• Bile

What is bile?

The liver produces bile which is a green/yellow liquid. Bile is formed from bilirubin, which comes from old red blood cells which have been broken down in the spleen. Bile helps the body to digest food by breaking fats down so they can be absorbed and enables the absorption of fat-soluble vitamins.

Bile also helps the body get rid of waste products such as bilirubin and excess cholesterol which it passes out into the stool (poo).

After bile has been produced by the liver it is transported to the gall bladder where it is stored. When food is eaten the gallbladder releases bile through bile ducts into the small intestine to help with digestion and remove waste products.

The liver gets rid of waste such as the breakdown products of old red blood cells, ammonia (which comes from proteins), medicines and drugs.

Liver blood tests (also known as liver function tests / LFTs) are carried out on blood samples in a laboratory. They are a common way of seeing how well the liver is working. They test the levels of particular proteins and enzymes in the liver as well as the level of bilirubin.

Liver blood tests are also used to monitor a child’s liver disease over time to see if the liver is getting healthier, getting worse or staying the same. Other blood tests will also need to be done to diagnose the cause of the liver disease.

The colour of urine (wee) and stool (poo) can provide information about the liver. As mentioned previously pale stool can be a sign of a problem with the liver, along with dark urine. Sending urine samples to the laboratory can give more information for the diagnosis.

This is a scan of the abdomen. It’s the same as the scan that pregnant women have to see their baby and doesn’t hurt at all. The ultrasound can show the size and texture of the liver and other organs such as the gallbladder, bile ducts, spleen and kidneys. It can also show the blood flow into and out of the liver.

A liver biopsy may be recommended if tests show that there could be a problem with the liver. The results of the biopsy may indicate if there is a problem with the liver or what it is. A biopsy may not be able to provide a diagnosis but may provide a clue to what other tests may be needed. They can also be used to monitor the condition.

A liver biopsy involves inserting a very thin needle through the tummy and into the liver. The needle takes a very small sample of the liver. That sample of liver tissue is then sent to the laboratory to be examined under a microscope.

Children may either have the procedure done with a local anaesthetic or with general anaesthetic (so they are asleep). When young people move to adult services they will have the biopsy done whilst they are awake using a local anaesthetic.

Normal range: 

• Total bilirubin: 3-20 mmol/l
• Conjugated bilirubin: less than 7 mmol/l

What does this show?

The total bilirubin level corresponds to the level of jaundice present.

The amount of conjugated bilirubin compared to the unconjugated bilirubin can show whether jaundice is caused by red blood cells breaking up too quickly (not a liver disease) or is due to a reduced flow of bile out of the liver.

Conjugated means that a sugar has been added to the bilirubin.

Normal range: 10 – 40 IU/I

What does this show?

High levels can mean there is liver inflammation present.

Normal range: 5-55 IU/L

What does this show?

High levels can mean bile duct inflammation or obstruction. The result can sometimes give information about bile production.

Normal range: Less than 350 IU/L

What does this show?

High levels can mean there is bile duct inflammation but ALP is not specific to the liver as it is also produced in other organs e.g. bones. Therefore, abnormal levels can be due to processes occurring in other parts of the body.

Normal range: 60 – 80 g/l

What does this show?

High and low levels can be used in consideration with the other LFT results.

Normal range: 35 – 50 g/l

What does this show?

Low levels can mean the liver is not making enough, that protein is being lost through the stool or a child is not well nourished.

Normal range: 

• PT (Prothrombin time): 12 – 15 seconds
• INR (International normalised ratio*): 0.9 – 1.2

What does this show?

The liver produces substances needed for blood to clot. Raised levels can mean there is less Vitamin K due to a reduced bile flow. If Vitamin K is given and the result is still raised, it may mean there is damage to the liver.

*INR is a standardised version of the PT for comparison, they both measure the same thing.

What is measured:

• Haemoglobin (Hb)
• White blood cell count (WBC)
• Platelets (Plt) – levels can fall in liver disease if the spleen is enlarged

What is measured:

• Urea and creatinine are waste products removed by the kidneys.

• Electrolytes include sodium, chloride and calcium.

A high or low level of sugar in the blood can sometimes be a sign of liver damage or a metabolic liver disease.

Ammonia is a waste product. It is converted into urea in the liver and is then removed in urine.

A higher level than usual may mean there is damage to the liver or an underlying metabolic condition.