Fatty Liver Disease in Cats: Causes, Symptoms, and Treatment

About Fatty Liver Disease in Cats

Fatty Liver Disease, also known as Feline Hepatic Lipidosis (FHL) or Fatty Liver Syndrome, is one of the most common liver diseases seen in cats.

It’s a complex type of feline liver failure that is still not fully understood. It can happen as a primary condition (i.e. as the only problem, on its own).

More commonly, it tends to be secondary to some other primary condition (e.g. diabetes mellitus, pancreatitis, inflammatory bowel disease, kidney disease, hyperthyroidism, some other type of liver disease).

The condition is typically seen in middle-aged, obese, or overweight cats that have stopped eating for a couple of days or more. Lipids (fats) accumulate inside the affected cat’s liver cells, and the consequent disease process then aggravates the original issue which caused the cat to stop eating in the first place.

Causes of Fatty Liver Disease in Cats

The main precipitating issue is the fact that the cat is carrying extra body weight in the first place. Then, when the cat stops eating for any reason, this extra fat in the cat’s body is mobilised, and the liver is flooded with excessive fats that accumulate inside liver cells. This then causes secondary problems in the cat’s metabolism, leading to the signs of Fatty Liver Disease.

There are many possible causes of this initial loss of appetite, ranging from a primary disease (such as those listed above) to a significant change in the cat’s lifestyle (e.g. sudden change of diet, or social change in the household such as a new pet, etc).

The problem is that the lack of food being absorbed into the bloodstream forces the body to tap into the body’s fat stores for its needs, and in a cat that is carrying too much body fat, this leads to the mass release of fats into the bloodstream at a greater level than the liver can tolerate.

Symptoms of Fatty Liver Disease in Cats

The initial problem is that the cat stops eating, for one of the reasons listed above. This may be a seemingly simple reason (e.g. diet changes) or it may be more serious (e.g. diabetes mellitus).

However, after a few days of being inappetent, the signs of Fatty Liver Disease itself begin to show.

There may be obvious, rapid weight loss with muscle wasting, the cat may become dull and unwilling to move around, and more serious signs include vomiting, diarrhea (or sometimes constipation), jaundice (yellowing of the gums), drooling (hypersalivation), and ventroflexion of the neck (pushing the head down to the ground, as if starting to do a tumbleturn).

Diagnosis of Fatty Liver Disease

This condition will be suspected by your veterinarian if the history and signs listed above are identified.

Physical Examination

On physical examination, the liver may be felt to be enlarged, and over 70% of cases exhibit jaundice (icterus, or yellow gums).

Blood Tests

Blood tests for liver function will show marked elevations of liver enzymes (such as ALT, GGT, ALKP, and AST), as well as high levels of bilirubin (hence the jaundice). Ultrasound will show a diffusely enlarged liver, and if computerised tomography (a CT scan) is carried out, the CT number of the liver will be raised.

Fine Needle Aspirate (FNA)

To confirm the diagnosis, as well as blood work, your DVM veterinarian may recommend a Fine Needle Aspirate (FNA) which uses a very small sample of liver tissue obtained by passing a very fine needle through the skin into the liver.

Characteristic changes are often seen in over 80% of the liver cells. A liver biopsy could be used to make a definitive diagnosis, but this is not generally necessary.

How Do You Treat Fatty Liver Disease in Cats?

The primary aim is to get the cat eating again: the issue is caused by metabolic changes that happen when a cat is not absorbing any food via their digestive system.

Since Fatty Liver Disease causes cats to lose their appetite, it is not always so easy to get them to take in the food that they need to get them onto the road to recovery.

Force-feeding has sometimes been carried out (restraining the cat, and either placing food into their mouths, and clamping their jaws shut, or using a syringe with liquid food). This approach is not recommended, as it causes stress and fear, and may lead cats to dislike food, even more, leading to an even longer period of inappetence.

A feeding tube (a flexible, rubbery type of tube) is needed for most cats, and this needs to be put in place under anaesthesia. Three types are available.

1. A naso-esophageal tube is placed through a nostril, to the back of the nose and then into the esophagus. These tubes are narrow, so they require the use of liquid food for feeding.
2. An esophagostomy tube or pharyngostomy tube is inserted through an incision in the side of the cat’s neck: these are wider bore, so allow the use of normal food that’s been liquidified to be given via a large syringe.
3. A gastrotomy tube may be placed directly into the cat’s stomach through the abdominal wall: these are not used so commonly, as they tend to be more complicated.

The aim is to feed the cat a daily allowance of around 50 kcal/kg of their ideal weight, using a balanced, digestible, “recovery” type of diet.

This should be given in frequent small meals (e.g. six times daily), starting with lower quantities and gradually building up as the animal’s body readjusts to the food intake.

Other supportive treatment is usually needed, including:

• Intravenous fluid therapy (“ a drip”)
• Vitamin K and vitamin B12 supplementation
• Liver-supportive medication such as L-carnitine and S-adenosyl-L-methionine (SAMe)
• Where indicated, medication to stop vomiting

It also important, of course, to concurrently treat any primary disorder that has led to the period of inappetence which was the precursor to Fatty Liver Disease.

Blood clotting problems can develop in this disease, so veterinary care may include monitoring red blood cell parameters on blood tests.

Careful monitoring by the veterinary team is important: in particular, “refeeding syndrome” is a common complication that can develop within the first two days of food ingestion recommencing. This is a life-threatening metabolic crisis caused by disturbances to the electrolyte levels in the blood that can be prompted by the sudden ingestion of food after a period of fasting.

The gradual reintroduction of food, in small quantities only, and slowly increasing, aims to prevent the onset of this issue.

As well as treating Fatty Liver Disease specifically, it’s also important that any underlying condition, as mentioned above, is also treated effectively.

The primary aim of all cat carers should be to prevent Fatty Liver Disease by ensuring that their cats do not become overweight or obese.

And all owners of overweight or obese cats should be aware of the fact that extra body weight is a key risk factor for this condition. They should be aware of the clinical signs of this condition, and they should be ready to take urgent action if their cat stops eating for more than a day.