Fatty liver disease or syndrome, more properly known as hepatic lipidosis, is a disease that affects a cat's liver. It is one of the most common acquired liver disease in cats, and it can be life threatening if not treated promptly. Symptoms can include lethargy, loss of appetite, jaundice, weight loss, weakness, and vomiting.
The majority of cats that develop fatty liver disease are middle-aged, overweight or obese cats that suddenly develop anorexia, or a refusal to eat, due to an underlying illness or extreme stress. The condition can quickly lead to liver failure and death without treatment. With treatment, however, which can be a lengthy process, most cats will recover from the condition.
Knowing how to recognize the signs of this serious disease, as well as how to prevent it, can help save your cat's life.
What Is Fatty Liver Disease?
The liver is a vital part of the digestive system. This organ performs a variety of critical functions related to digestion, including processing fats and carbohydrates to make energy, synthesizing proteins and vitamins that are crucial to healthy cellular function, serving as a storage space for vitamins and iron, producing several different hormones, and breaking down toxins in the bloodstream so they can be eliminated from the body.
When a cat, especially an overweight or obese cat, develops anorexia, or a refusal to eat, for more than three or four days, the stage is set for the development of hepatic lipidosis. The cat's liver turns to the rapid breakdown of stored fats to serve as a source of energy, but if the liver is unable to process fats as quickly as they are broken down, the liver cells become engorged with fat. This causes the cells to swell and impairs liver function. If fatty liver disease is left untreated, it can progress to complete liver failure, which is often fatal.
Symptoms of Fatty Liver Disease in Cats
Most often, fatty liver disease is preceded or accompanied by a cat suddenly developing an aversion to its food and refusing to eat. This can happen for a variety of reasons, including underlying illness or extreme stress. The refusal to eat causes the cat to rapidly lose weight—it is not unheard of for the feline to lose as much as 25 percent of its weight—which is often the first symptom of the disorder. Other symptoms develop as the liver struggles to process fat.
You'll likely first notice that your cat isn't eating as much as normal or is even refusing to eat anything at all. The cat might also refuse to drink. This anorexia quickly leads to weight loss, which can be extensive, especially if your cat was overweight to begin with.
As the liver begins to fail, jaundice often appears. This is a yellowish tint to the cat's eyes and skin caused by a buildup of bilirubin in the blood due to liver impairment. The cat might have diarrhea or vomiting, and will generally appear lethargic and weak. Your cat might become shyer than usual or hide.
Causes of Fatty Liver Disease
Any scenario that causes a cat to suddenly stop eating can cause fatty liver disease. While occasionally the reason might be intense environmental stress, such as a recent move, new member of the household, or a change in schedule, most often it's an underlying illness that causes the cat to lose interest in its food.
As a carnivore, a healthy cat's diet should contain a minimum of 50 percent protein, at least 30 percent fat, and less than 10 percent carbohydrates. A healthy feline liver has no problem in processing that fat as the cat consumes it, breaking the fat down and converting it into energy that's sent throughout the body.
When a cat suddenly stops eating, however, the liver tries to make up for the shortfall of calories by pulling fat out of storage and breaking it down into a usable source of energy. Unfortunately, if the cat has an underlying health problem, the liver can be too sluggish to break down the fat quickly enough, and so the fat begins to clog up the organ's cells. This reduces the liver's ability to function even further, and can eventually cause it to fail altogether.
Diagnosing Fatty Liver Disease in Cats
If you suspect your cat has fatty liver disease or it has stopped eating for more than a day or two, it should be seen by a veterinarian as soon as possible. A veterinarian will perform a full physical examination, take a full history, and obtain a blood sample to perform a complete blood count and check organ function, as well as look for signs of underlying illnesses.
Specific enzymes in the blood can provide information that helps the veterinarian determine whether or not the liver is functioning well. These enzymes may provide an indication that your cat has fatty liver disease or another problem causing the same symptoms. Your vet might also want to do an ultrasound of the liver, which can reveal swelling due to hepatic lipidosis.
In order to definitively diagnose a cat with fatty liver disease, however, a biopsy of the liver is required. This is usually performed by inserting a long needle through the cat's skin and into the liver to retrieve a small sample. If the cat has hepatic lipidosis, microscopic examination of the liver sample will reveal excessive fat in and around the cells.
Because many cats with fatty liver disease are dehydrated when first brought to the animal hospital, they are often started right away on IV fluids. Once the cat is rehydrated, the process of restoring food intake begins. But because these cats are typically unwilling to eat enough to sustain themselves, the standard treatment consists of surgically implanting a feeding tube either into the cat's esophagus or directly into its stomach.
A special liquid diet that is formulated for cats recovering from fatty liver disease is introduced slowly through the feeding tube, allowing the cat's liver to gradually recover from its strain while still supplying the needed calories and nutrients. Typically, your cat will remain in the veterinary hospital for a week or so. During this time, it will be fed through the tube and may also receive medications to help heal the liver, extra fluids through an IV, and any treatments required to stabilize underlying health issues.
Once your veterinarian feels that your cat is stable enough to leave the hospital, you will be instructed on how to continue the tube feedings at home. Generally, this involves using a syringe to inject a special prescription food mixed with water into the feeding tube three to five times per day, and then flushing the feeding tube with sterile water to keep it free from clots.
Most cats require at least six to seven weeks of tube feeding. During this time, your vet may advise you to also offer your cat its favorite food by mouth once a week or so. This will allow you to determine when the cat's normal appetite returns. As your cat begins to eat normally, you will reduce the amount of the tube feedings, as per your veterinarian's instructions.
Once your cat is eating normally for at least three or four days, your vet will remove the feeding tube. Do not attempt to remove the tube yourself.
Prognosis for Cats With Fatty Liver Disease
If your cat receives prompt treatment before the hepatic lipidosis progresses to full liver failure, its prognosis is good. Most cats recover from the condition and do not experience another episode. However, if your cat has a serious underlying condition that triggered the fatty liver disease, and that condition is not treatable, then your cat's prognosis is more guarded.
How to Prevent Fatty Liver Disease
The best way to prevent fatty liver disease is to keep your cat at a healthy weight. This can be accomplished through a balanced diet with the right amount of calories and nutrients for your cat's age, activity level, and size. Your cat should exercise daily, as well, which can take the form of play sessions chasing a ball or string, or similar fun interactions.
If your cat has a chronic health condition, such as hyperthyroidism, kidney disease, or liver disease, then it is even more important to be vigilant about your cat's eating habits. Should it suddenly refuse to eat, it's time for a call to your veterinarian.
Hepatic Lipidosis in Cats (Fatty Liver Syndrome in Cats). VCA Hospitals.
Hepatic Lipidosis. Cornell University College of Veterinary Medicine.
Hepatic Lipidosis: Dangers, Diagnosis and Treatment. BluePearl Specialty& Emergency Pet Hospital.
Feline Hepatic Lipidosis. Merck Veterinary Manual.
Demystifying the Cat Diet. Animal Medical Center of Chicago.