Liver Disease in Cats

Overview:

The liver is the largest internal organ of the body.  It is located in the abdomen, under the diaphragm. It performs many functions which are essential to life.

• Cleans the blood by removing medications & toxins

• Regulating chemicals in the blood

• Produces & secretes bile, which aids digestion & absorption of fats. Bile is a greenish-yellow fluid which consists of bile acids & waste products  such as bilirubin. It is made by the liver & stored in the gall bladder.

• Produces specific enzymes which aid digestion of food

• Converts most sugars into glycerine which it stores up as glycogen until required

• Fat soluble vitamins A, D, E and K need bile in order to be absorbed by the body

• Production of blood clotting factors

• Manufacture of certain hormones

• Breaks down haemoglobin creating metabolites that are added to bile as pigment.

• The liver changes ammonia, a toxic by product of protein metabolism into urea, which is excreted in the urine.

The liver  is divided into sections (known as lobes), each of which is composed of thousands of structural & functional units (hepatic lobules).

Two blood vessels enter the liver. The hepatic portal vein contains  de-oxygenated blood from the spleen, pancreas & digestive system & the hepatic artery contains oxygen rich blood from the lungs.

Liver Disease:

There are several causes of liver disease in cats, which include:

• Hepatic Lipidosis (also known as Idiopathic Hepatic Lipidosis or Fatty Liver Disease). Hepatic Lipidosis is a common liver disease which is caused when a cat becomes anorexic (stops or reduces the amount of food it's eating), the body begins to use fat stores as fuel. These fat stores are sent to the liver, to be broken down to supply nutrients.  Unfortunately, the liver sometimes becomes overwhelmed & is unable to process this fat as quickly as necessary, leading to a build up of fat in the liver, which  interferes with normal liver function.

• Cholangitis/cholangiohepatitis complex: This is a number of related inflammatory & or infectious disorders of the liver and/or the biliary tract. Cholangitis relates to infection or inflammation of the bile duct & cholangiohepatitis is inflammation of the biliary system & by extension the liver. Causes of infection may often include FIP, Pancreatitis, IBD, bacterial infection, parasitic infection (including toxoplasmosis).

• Damage by toxins (Toxic Hepatopathy):  This is caused by exposure to drugs, toxins or lack of blood to the liver.

• Cancer: There are many different types of tumour which affect the liver. Primary liver cancer (liver beginning in the liver) is uncommon in cats. Most cancers of the liver originate from some other site & spread to the liver.

• Portosystemic shunt (also known as liver shunt): Portosystemic shunts are abnormal communications between the portal & systemic venous system which allows intestinal blood to be delivered to the systemic circulation prior to hepatic detoxification. A shunt means that blood bypasses the liver, resulting in blood not being detoxified by the liver & a rise in toxins. Portosystemic shunts may be congenital or acquired, most shunts in cats are congenital & cats demonstrate clinical signs within 12 months of age.

What are the signs of liver disease in cats?

Symptoms may vary depending on what has caused liver disease, but common symptoms include:

• A common sign of liver disease is icterus (also known as jaundice). Signs of icterus are yellowing of the eyes, skin & mucous membranes.

• Loss of appetite

• Abdominal effusion

• Weight loss

• Polyuria (increased urination)

• Polydipsia (increased water consumption)

• Enlargement of the liver

• Lethargy

• Diarrhoea

• Vomiting

• Seizures

• Bad breath

How is liver disease diagnosed?

Your veterinarian will perform a physical examination of your cat & will want to run several tests, including a biochemical profile to look at;

• ALT (alanine aminotransferase) is an enzyme produced in the liver cells.  The ALT test determines the level of this enzyme in the blood, which increases when damage to the liver cells has occurred.  

• AST (aspartate aminotransferase) is an enzyme also found in skeletal & cardiac muscle cells, the brain & red blood cells. Elevated AST in the blood is also an indicator of liver disease, although as it is found in other organs, it is not as specific for liver cell injury as elevations in ALT.  

• Bilirubin: This is a major breakdown product of red blood cells. When red blood cells wear out they are trapped in the spleen and destroyed, releasing bilirubin into the blood. This type of bilirubin is called unconjugated. This bilirubin is transported in the blood to the liver, where it is taken up & conjugated (joined with glycuronic acid). This conjugated form may either be stored in the liver cells or excreted into the bile.  Bilirubin levels are increased in cats with liver disease, gallbladder disease or have excessive destruction of  red blood cells (known as hemolysis).

• Low blood urea nitrogen.

• Low blood glucose.

• Low potassium (hypokalemia).

• Low cholesterol.

• Albumin: This is a major protein of the blood plasma. It is manufactured by the liver. Low levels of albumin in the blood can be a sign of liver disease.

• Complete blood count

• Urinalysis

• Thyroid testing

• Bile acids tolerance test

• Ultrasound: An ultrasound can give your veterinarian an idea of the size & shape of your cat's liver & gallbladder, and detect gallstones & biliary obstruction (blockage of the flow of bile from the liver).

• X-Ray:  An x-ray may be taken to give your veterinarian an idea of the size & shape of your cat's liver. X-ray may also detect the presence of tumours.

• Biopsy: A liver biopsy is taken to determine the exact type of liver disease. This may be done at the same time as the ultrasound.

• Serologic Testing: Testing for diseases such as FeLV, FIV, FIP & toxoplasmosis may be taken as these diseases are associated with some liver disorders in cats.

How is liver disease treated?

Treatment depends on the cause of liver disease.

Hepatic Lipidosis:

• Intensive nutritional support. Most frequently this involves feeding a  calorie dense, high protein  food via a feeding tube either directly into the stomach or esophagus. This type of  feeding will usually be required for 6 - 8 weeks. 

• Fluid & electrolyte therapy if the cat is dehydrated. 

Cholangitis/cholangiohepatitis complex:

• Supportive care with IV or subcutaneous fluids & nutritional support.

• If the cause is bacterial, antibiotics will be prescribed.

• Medication to control vomiting if necessary.

• Corticosteroids may also be helpful in cats.

Damage by toxins:

• Supportive care.

Portosystemic Shunt:

• Surgical ligation.

• A prescription diet which is restricted in protein may be recommended.

• Supportive care, where necessary.

Please note:

The medical articles on this site have not been written by a veterinarian & should not be considered a replacement for a veterinarian visit. The articles are provided for informative purposes only.

Always seek immediate veterinary advice for any problems (health or behavioral) in your pets. 

While great care has been made in the creation of these articles, we cannot guarantee the accuracy or omissions on these pages. If in any doubt whatsoever, seek professional medical advice.