It may seem counter intuitive, but when the doctors at the Animal Clinic at Thorndale see an over weight cat that is ill or has gone through a major stress in its life, we worry most that it will stop eating. While you might think that fasting would help this cat lose weight, our doctors know that fasting cats can quickly develop a potentially fatal metabolic derangement. In the fasting state, the excess body fat is mobilized to the liver to be used for energy. However, in the cat, without incoming additional nutrients, that fat is not utilized properly. Instead, that fat sits in those liver cells, expanding them, making the cat feel sicker and even less likely to eat. This spirals into a vicious cycle and without medical intervention, this cat could die from hepatic lipidosis, or fatty liver syndrome. You don’t have to be a “fat cat” for this to happen to you. It is just that obesity allows for more fat to cause more damage faster. Even athletic cats can develop a fatty liver when they quit eating.
Fatty Liver Syndrome
Feline Hepatic lipidosis, also known as fatty liver syndrome (FLS), is one of the most common liver disorders of the cat. It is also seen in horses, dairy cows and rarely in very young puppies. In dogs, however, it is not thought to cause a significant illness. In humans, it is a serious disease which can occur with pregnancy.
Contributing Factors
In most cases, the cause remains undetermined (Idiopathic FLS). Obesity and a period of anorexia (not eating) lasting at least one week are common historical findings. Less commonly, the fatty liver syndrome occurs secondary to a disease which might lead to anorexia, such as cancer or an infectious disease.
Prevalence
Idiopathic fatty liver syndrome is most common in cats that are overweight. Many of these cats have lost up to 25% of their body weight when the liver problems are discovered. Also, most cats with idiopathic fatty liver are middle aged and female.
Clinical Signs
In the anorexic cat, fat is broken down to supply energy for normal metabolism. As this fat is mobilized, it is deposited in the liver. Without an adequate source of dietary protein, the fat cannot be removed from the liver. It continues to accumulate until liver failure eventually results. The fat fills up and swells the liver cells, making the cat feel sicker. This again causes the cat not to eat, mobilizing more fat to go to the liver. A vicious cycle is set up with fat mobilization and anorexia.
With time, the cat usually becomes icteric or jaundiced, as evidenced by a yellow color in the whites of the eyes or in the skin. As toxins normally processed by the liver continue to build up in the blood, the nervous system becomes affected. Depression, seizures, disorientation, and head pressing will occasionally occur. Cats can die from fatty liver syndrome.
Causes/Transmission
As noted above, for most cats, a cause is not determined. In a few cases, fatty liver develops secondary to a disease that causes anorexia. Some cats quit eating in the face of stress. Major changes in the household, though sometime unavoidable, can lead to anorexia in cats. All cats that are not eating, whether or not obese, can potentially develop fatty liver syndrome.
Diagnosis
Diagnosis of the FLS is made from blood tests for liver function, and ultrasound examination of the liver, and from a liver biopsy or fine-needle aspirate. The latter involves inserting a very tiny needle through the skin and into the liver, removing a small number of liver cells, and examining those cells under the microscope. The FLS cat will have a large amount of fat in and among the liver cells.
Therapy
This disease is treatable, but aggressive intervention is necessary. The main thrust of treating FLS is geared toward nutritional support of the cat until it begins to eat voluntarily. A consistently high quality diet will allow the liver to resume functioning so it may remove the fat. This does not occur quickly; it takes an average of 6-7 weeks. Therefore, a method of tube feeding must be used to allow you to feed your cat at home.
Several routes are available for feeding the cat. The esophagostomy tube is a small rubber tube that enters through the cat’s skin in the neck. It goes into the esophagus so that food can be delivered to the stomach. It does not go into the stomach because of complications that can arise.
A special food mixture is syringed through the tube three to five times per day. This food is formulated to meet the cat’s nutritional needs; it should not cause vomiting or diarrhea. A prescription liquid diet may be used.
- Be certain to feed the directed amounts of food at the specified time intervals
- When the food has been injected, inject 5 ml of tap water through the tube so food does not remain in it; replace the cap in the tube.
- Any remaining food should be stored in the refrigerator. Before the next feeding, it should be warmed to body temperature under hot tap water or in a microwave oven. If you heat it in a microwave oven, be sure to thoroughly mix the contents prior to feeding because of uneven heating. Also, always check the temperature prior to feeding to be sure that it is not too hot.
Persistence is essential. The average cat requires 6-7 weeks of feeding before it begins to eat. At least once weekly, offer your cat a small amount of its favorite food so that you will know when its appetite returns. The esophagostomy tube will not hinder chewing or swallowing. After your cat has been eating well for 3-4 days, it should be returned to the hospital for tube removal. Removal of the tube is simple and does not require anesthesia; however, you should not attempt to remove the tube yourself.
Prognosis
In most cases of idiopathic FLS, the prognosis is good if nutritional intervention is undertaken before the onset of liver failure. When the underlying cause of the FLS is untreatable, the prognosis is not good.
Vomiting is an important sign in determining the prognosis. Although many cats with the FLS will vomit occasionally, those that vomit repeatedly have a lesser chance of recovery. Repeated vomiting usually means that the liver failure is very severe or that a disease of the pancreas (pancreatitis) is also present. Either may result in the cat not recovering.
Transmission to Humans
There is no associated health risk for the owners of cats with hepatic lipidosis.
Prevention
It is possible for idiopathic FLS to occur again. It is helpful for owners to be observant of the cat’s food intake and guard against stressors which might precipitate anorexia. Maintaining an ideal body weight and avoiding obesity in affected cats is advisable.