Dog - Jaundice

What is jaundice?

Jaundice is the name given to the yellow pigment found in the blood and in the tissues which can most easily be seen in jaundiced patients in the gingiva (gums), the sclera (white part of the eyes), and the pinna (ear flap). However, if any of these tissues normally have a dark colour, as occurs with many dogs, the jaundice will probably not be seen.

What causes jaundice?

Basically it is due to an excess of the yellow/orange bile pigment, bilirubin, in the blood. There are three main causes:

1. Haemolysis occurs due to the destruction of red blood cells. It can be intravascular, occurring within the blood vessels or extravascular when it occurs in the spleen and liver.
2. Liver disease. Any disease that causes destruction of liver cells or causes bile to become trapped in the liver can cause jaundice.
3. Obstruction of the bile duct. The bile duct carries an important fluid for digestion (bile) from the gall bladder to the small intestine. Obstruction can occur within the gall bladder or anywhere along the bile duct.

How is the cause of the jaundice determined?

Haemolysis

Haemolysis, liver disease and bile duct obstruction all have various causes, therefore diagnosis of the cause of jaundice usually involves a series of laboratory tests commencing with blood tests which will give an indication whether haemolysis, liver disease or bile duct obstruction is the underlying cause. Once that has been determined further tests are then necessary to further define the diagnosis.

Haemolysis for example can have many causes including toxic plants, chemicals, drugs, certain blood parasites, heartworms, autoimmune diseases, etc. Many tests may be needed to determine which of these is the cause.

Liver disease

The routine biochemical tests carried out on the initial blood sample include several tests that are specific for liver disease. If these are abnormal further tests, probably including a liver biopsy, may be necessary.

What causes liver disease?

Like haemolysis liver disease has a variety of causes including bacterial and viral infections, toxic plants, chemicals, drugs, cancer, autoimmune diseases and also certain breed specific liver problems.

Bile duct obstructions

Dogs with obstructed bile ducts are usually extremely jaundiced. The yellow colour can often be readily seen in the skin as well as in the white of the eye and the mucous membranes. Nevertheless further tests are necessary to establish diagnosis and ultrasound examination is the most accurate and non-invasive test presently available.

What are the common causes of bile duct obstruction?

These include pancreatitis and trauma (e.g. following falls, kicks or road traffic accidents).

How is jaundice treated?

As it will now be realised jaundice is not a disease in itself but a sign that disease is present. Once the cause of the jaundice has been established treatment of the disease, if possible should bring about a resolution of the jaundiced state. Unfortunately jaundice is a very complex problem.

Please also refer to the handout on Early renal disease.