Feline Fatty Liver Syndrome

What is it and why does it occur?

Feline Fatty Liver Syndrome (FLS) is a liver disease that occurs in cats. It is also known as hepatic lipidosis, which means infiltration of the liver with fats, or lipids. FLS is among the most common liver diseases in cats.

In most cases, FLS occurs in cats that have lost their appetite and stopped eating. In other words, it occurs in cats with anorexia. Fatty liver syndrome is more likely to occur in a cat that was grossly overweight (obese) before it went off its food. When an animal becomes anorexic, the body breaks down its fat stores to use as a source of nourishment. However, in FLS, the fat is delivered to the liver so rapidly that the liver cannot process it all. As a result, fat begins to build up within and between the liver cells, which can lead to liver failure.
Liver failure causes jaundice, in which the white part of the eye, pale skin, and membranes such as the gums become yellowish in color. By this stage, immediate and intensive treatment is often necessary to save the cat's life.

How is FLS diagnosed?

To diagnose FLS, your veterinarian may recommend some laboratory tests. First, a blood test to evaluate the liver function, and second, a liver biopsy or aspirate. The blood test simply involves taking a small amount of blood from a vein in the cat's forearm or neck and sending it to the laboratory for analysis. The results indicate whether the liver is functioning normally, and if it is not, how severe the liver compromise is. The results do not confirm the presence of FLS, just that the cat has liver disease.

To confirm a diagnosis of FLS, it is necessary to perform a liver biopsy or aspirate. Liver biopsy is usually performed by passing a biopsy needle through the skin into the liver and sampling a tiny piece of liver. The skin and underlying tissue is first numbed with local anesthetic, so the cat does not feel the needle or the sampling procedure. The sample of liver is then sent to a veterinary pathologist for examination. Liver aspirate involves inserting a small needle through the skin into the liver, and drawing out (aspirating) some liver cells. These cells are then examined using a microscope. Unlike biopsy, the results of this test may be available immediately. With either test, larger than normal amounts of fat may be found in the liver cells and in the rest of the sample.

Another important part of evaluating a cat with FLS is investigating why the cat stopped eating. Depending on the cat's history and what your veterinarian finds during physical examination, other tests may be necessary. This part of the evaluation is important because if the cause of the anorexia cannot be found and corrected, the prognosis for recovery from FLS is not good.

How is FLS treated?

Along with treatment for the cause of the anorexia, treatment of FLS involves nutritional support until the cat's appetite returns. Providing a highly nutritious diet stops the process of using fat stores for nourishment, which allows the liver to remove the accumulated fat and return to normal function. However, this process often takes at least 6 weeks. In the meantime, it is usually necessary to force-feed the cat.

How can I provide nutritional support at home?

Force-feeding a cat for several weeks is most easily accomplished using a feeding tube. This may sound difficult and involved, but it is simple and something any cat owner can easily do at home. Before sending your cat home, your veterinarian will surgically insert a feeding tube that allows you to syringe a food mixture directly into your cat's stomach. Depending on your cat's nutritional needs and on your schedule, you'll be advised to feed your cat through the tube 3-5 times per day.

How will I know when it's time to remove the tube?

It may take several weeks for your cat's appetite to return. At least once a week, offer your cat a small amount of food; something you know it would normally like to eat. The feeding tube will not interfere with eating, so if your cat is interested in eating, start giving it small amounts of food at each feeding. Once your cat has been eating well for 3 or 4 days, schedule an appointment for your veterinarian to remove the feeding tube. Tube removal is a simple procedure that does not require general anesthesia, but it is not something you should attempt to do yourself. During the visit, your veterinarian will also review your cat's progress.

Instructions for at home care of Feline Fatty Liver Disease

To feed your cat using the feeding tube, follow these simple steps:

1. Place the following ingredients in a blender and set it on "liquefy" (the fastest speed) until the food is a smooth mixture.

Then pour the mixture through a kitchen strainer and discard any food particles that remain in the strainer.

2. Remove the cap from the end of the feeding tube and, using the syringe provided, slowly inject ________ cc* of the food mixture into the feeding tube _____ times per day.

THIS IS A TOTAL OF _________ cc PER 24 HOURS.

Inject the food slowly (about 1 cc per second), and raise your cat's chest or front feet so that the mixture slides easily into the stomach.

(* cc is a measure of volume, marked on the side of the syringe)

3. After injecting the food mixture, inject 5-10 cc of lukewarm water through the tube, then replace the cap on the tube. It is important to flush the tube with water after each meal to make sure no food remains in the tube to dry out and clog the tube at the next feeding. It is also important to make sure the tube stays tightly capped between feedings.

4. Store any remaining food in the refrigerator for the next feeding. Warm it to body temperature under hot tap water or in a microwave oven before feeding it. If you are using a microwave, thoroughly mix the food to make sure it is heated evenly, and always check the temperature of the food before feeding it to make sure it is not too hot.

Note: The food mixture is formulated to provide all of your cat's nutritional needs. It should not cause vomiting or diarrhea. Call your veterinarian if vomiting or diarrhea develops.

by William M. Fraser, D.V.M.

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