Feline Liver Disease

The liver is made up of millions of cells called hepatocytes. Digested food products arrive at the liver from the small intestine. They travel via the Hepatic portal vein. The liver has a large storage capacity and excellent regenerative capabilities.

The liver carries out approximately 1500 functions including:

• Removal of toxins and nitrogen
• storage of iron, fats and vitamins
• regulation of body heat
• production of bile, plasma proteins, vitamins
• metabolises proteins and fats
• changes glycogen to glucose when energy is needed
• destroys old red blood cells

Common Liver Diseases in cats

(1) Feline Hepatic Lipidosis
(2) Portosystemic shunt
(3) Cholangitis (inflammation of the biliary ducts)
(4) Cholangiohepatitis (inflammation of the biliary ducts and liver)
(5) Portal hypertension (increase in blood pressure in the portal vein)
(6) Bile duct obstruction
(7) Chronic Hepatitis and cirrhosis

Early signs of liver disease include:

Anorexia, diarrhoea/constipation, vomiting, weight loss, pyrexia (fever), no jaundice, polydipsia (excessive urination), polyuria (increased urination).

The veterinary surgeon may have recommended a specialist veterinary diet. Usually, the diagnosis is based on a blood sample which shows raised liver enzymes. According to Dr. David Twedt of Colorado State University speaking at the North American Veterinary Conference, 2003, in most cases, when liver enzymes are raised there is an (undiagnosed) problem elsewhere in the body which is having a secondary effect on the liver.

Hepatic Lipidosis

Also known as fatty liver disease, where fat accumulates in the liver. Obese cats which lose weight rapidly can be predisposed to hepatic lipidosis. However, it can also occur in lean cats.

Symptoms usually include: Icterus (jaundice), anorexia, malaise and occasional vomiting.

Hepatic Lipidosis can occur after the cat has been fasted/starved this is because after starving fatty acids accumulate in the liver and as a result the amino acid intake is inadequate (due to anorexia and perhaps because of vomiting).

• Amino acids (the building blocks of proteins) are essential in recovery of hepatic lipidosis and the cat may need to be force fed by syringe feeding. If this is not possible tube feeding may be advised.

• Vitamin B supplements are also advised, especially B1 and B12.

• A protein deficiency is not thought to cause this disease but may encourage the development of hepatic lipidosis but is not thought to cause the condition. Protein supplementation may be recommended.

• A deficiency in carnitine does not seem to cause hepatic lipidosis but studies show that foods supplemented with L-carnitine can help an obese cat to lose weigh safely. Carnitine is found naturally in meat, red meat is the richest source. It is also available in chicken, fish, eggs, and milk. Vegetables do not contain carnitine. Carnitine can also be synthesized in the liver from the amino acids methionine and lysine if sufficient ascorbic acid, niacin, pyridoxine and iron are present.

Portosystemic shunt

This is usually a congenital (present from birth) defect. The blood is shunted from the intestines into circulation by-passing the portal vein, thus the toxins are not removed from the blood.

Cholangitis

This is usually caused by a bacterial infection and E. Coli is often present. Treatment is normally successful when using antibiotics and corticosteroids.

Cholangiohepatitis

This disease is often caused by liver flukes and may progress into cirrhosis if not treated. The prognosis is favourable. Prednisolone is often used for inflammation and Praziquantel for the liver flukes.

Portal hypertension

This condition usually occurs secondary to hepatitis and cirrhosis.

• Sodium and Chloride. Excess levels of these minerals should be avoided as they may increase blood pressure. Recommended levels for sodium are 0.20 – 0.35% for cats.

Chronic Hepatitis and cirrhosis

Unvaccinated animals may be at risk of viral hepatitis.

• Adequate protein is important (but excessive levels should be avoided) unless the cat has severe cirrhosis.

• Antioxidants, Vitamin C and E are helpful in this condition.

Diet and health

Vitamins. Deficiencies of water soluble vitamins may occur because of an inadequate intake (due to anorexia) or through vomiting and urinary losses. Commercial pet foods have enough water soluble vitamins to support liver disease. However, vitamin supplements may be needed if the owner is feeding a home made diet, if the cat has excessive polydipsia and polyuria and if the cat has been anorexic for a long

Vitamin K. The cat may be deficient in this essential blood clotting vitamin. Alternatively, there may be sufficient quantities of Vitamin K but the liver may be unable to turn it into its active form. Vitamin K supplements are often given before surgery e.g. for liver biopsies. Vitamin k is found in liver, fish oils, yoghurt, sea kelp, vegetable oils and leafy green vegetables.

Fibre. Fibre can be beneficial as it reduces the availability of nitrogenous waste in the gastrointestinal tract. Fibre may also bind bile acids, toxins and bacterial products.

Potassium: A deficiency may cause hypokalemia (abnormally low potassium concentrations in the blood). Symptoms of hypokalemia include muscle weakness and it can exacerbate anorexia. Potassium is found in a variety of foods including meat, poultry, fish and nuts.

Fat: There is no need to restrict fat levels in cats with liver disease, unless the cat is showing signs of steatorrhoea (excess fat in the faeces due to malabsorption).

Zinc: In humans with hepatic disease a zinc deficiency is often present. Zinc is essential for the action of enzymes and a deficiency may adversely affect ammonia metabolism. Zinc is found in shellfish, brewer’s yeast, meat, liver, eggs, fish, nuts and some vegetables.

Taurine: Cats with liver disease may be deficient in Taurine (perhaps due to inadequate intake from anorexia). A cat’s liver has a limited capacity to produce the amino acid, Taurine. It is found in animal tissues but is not in plant material; therefore vegetarian diets fail to provide sufficient amounts of this nutrient.
A deficiency causes visual impairment which may cause the cat to bump into things, failure to reproduce successfully and heart disease. Taurine is thought to be especially important for cats with hepatic lipidosis, this is because taurine is an important component of bile acids (the bile acids absorb fats). Taurine is found in red meat, fish and eggs.

A diet containing moderate levels of high quality protein and fat along with complex carbohydrates is suggested for the management of liver disease.

High quality protein is important so that it contains all the essential amino acids the cat may need.

It is important to feed multiple small meals since the liver has a decreased ability to store food.

It is important the daily feeding rates are kept to a minimum to help avoid excess nutrients.

Feeding Advice

1. All family members must agree to cooperate by ensuring that the correct diet is followed i.e. no tit-bits, table scraps or other foods.

2. Gradually introduce the new food. Gradual introduction, by allowing a slow change in intestinal bacteria, minimises the risk of digestive upset.

3. Quantity of food. It is better to feed slightly less food, which will be properly absorbed rather than a large quantity, which could cause an upset.

Success depends on feeding the right amount for each individual.

 

Common pet health problems
John Burns Pet Health Management Programme