Jaundice in Cats
The term jaundice describes a yellow discoloration of the skin. This can most easily be appreciated by looking at the whites of the eyes, and the mucous membranes (ie the third eyelids and gums). Jaundice reflects an increase in the levels of bilirubin (a pigment in bile) in the blood. Bilirubin forms from the breakdown of old red blood cells, it is processed in the liver and excreted into the gallbladder, which empties into the small intestine.
What can cause jaundice?
Jaundice is most often associated with liver disease, however it can be caused by anything that will result in an increase in bilirubin in the bloodstream. This can therefore be a result of increased production of bilirubin as occurs with increased breakdown of red blood cells (haemolysis; pre-hepatic jaundice), or because of reduced excretion of bilirubin, which can be due to disease within the liver (hepatic jaundice) or a disease process causing obstruction of the outflow of bile from the gallbladder (post-hepatic jaundice).
Pre-hepatic jaundice, caused by excessive breakdown of red blood cells can occur secondary to a number of disorders such as Mycoplasma or feline leukaemia infection (see anaemia information sheet for more details).
"Pre-hepatic jaundice, caused by excessive breakdown of red blood cells can occur secondary to a number of disorders such as Mycoplasma or feline leukaemia infection."
Hepatic jaundice can be caused by a variety of liver diseases such as neutrophilic hepatitis and/or cholangitis (a bacterial infection of the liver and/or bile ducts), lymphocytic cholangitis (a specific type of inflammation of the liver with an uncertain cause), hepatic lipidosis (fatty infiltration of the liver; occurs as a consequence of inadequate food intake particularly in overweight cats), cancer of the liver or Feline Infectious Peritonitis (see information sheet on Feline Infectious Peritonitis).
Post-hepatic jaundice results from disorders that may block the outflow of bile from the gall bladder. This may occur as a consequence of inflammation in the pancreas (pancreatitis) since the pancreas is situated very close to the ducts that allow flow of bile from the gall bladder to the small intestine, a tumour in the pancreas, small intestine or bile ducts or gall stones (uncommon in cats).
What other signs might my cat show?
In addition to the jaundice, your cat is likely to be showing some other signs of disease. This will depend to some extent on the cause of the jaundice, however often additional signs are vague and non-specific such as lethargy, loss of appetite and vomiting.
How will the cause of the jaundice be identified?
If the jaundice is pre-hepatic, anaemia will also be present. This can be identified by taking a blood test and measuring the amount of red blood cells. If anaemia is not present, this excludes the various causes of pre-hepatic jaundice and so the next thing your veterinarian will need to do is distinguish between hepatic and post-hepatic jaundice. This is very important because if the bile ducts leaving the gall bladder are obstructed and the gall bladder is unable to be emptied, it will eventually rupture, resulting in the leakage of bile into the abdomen, which is a severe often fatal condition. Other blood tests can help to give an indication of whether there may be disease within the liver. The easiest and quickest way of determining whether extra-hepatic jaundice is present is an ultrasound examination to assess whether the gall bladder is very big and whether the bile ducts are wider than they should be, indicating that they are obstructed. This is quite a specialized technique and so your cat may have to be referred to a specialist for this. If hepatic jaundice is present, further tests may have to be performed to identify the cause of the hepatic jaundice (see information of liver disease)
How is jaundice treated?
The treatment of jaundice will depend on the underlying cause. If extra-hepatic jaundice is present, surgery may be required to remove the blockage of the bile ducts. If there is infection in the liver, a long course of antibiotics may be required. If fatty infiltration (hepatic lipidosis) is identified, your cat may need a feeding tube placed, to allow administration of plenty of food to reverse these changes. Your vet will provide more details on the treatment, once the cause of the jaundice has been identified.
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