Fatty Liver Disease, or Hepatic Lipidosis, is one of the most common liver disorders of cats in the developed world. It typically occurs when an overweight cat loses weight too fast. Typically, this is either because of an excessively aggressive diet plan (good idea, but poor execution!), or due to some other disease process that results in a loss of appetite.

Unfortunately, fatty liver disease is often in itself more dangerous to the cat than the underlying problem. Without rapid and effective treatment, it is frequently fatal.

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Why does it happen?

To a great extent, the underlying cause is irrelevant – it may be a “crash diet”, or an injury or illness (e.g. a broken jaw) that means the cat cannot eat, or an illness that means they don’t want to eat (e.g. underlying liver or kidney disease). Whatever the reason, the cat’s body suddenly doesn’t have enough fuel.

As a result, body fat is mobilised. Fat deposits under the skin and in the abdomen are broken down and sent to the liver to be turned into fuel – glucose – to keep the body going. The trouble is that cats’ livers (like cats as a whole!) don’t cope with change very well. The liver quickly absorbs all this fat that’s being sent to it, but it can’t process the fat as fast as it’s absorbed.

How does it impact liver function?

The biggest factor that determines whether Fatty Liver Disease occurs or not is this – how much “spare” or “extra” fat was the cat carrying before they became ill or stopped eating? If they had been a healthy weight, it is likely that the liver will cope. If, however, they were significantly overweight or obese, the extra fat swamps the liver.

Now, the liver of a cat (or indeed any mammal) has lots of different functions (over 150 at least, and probably over 1000!). Unfortunately, liver cells that are completely clogged and full of fat are unable to operate properly, as the delicate structures inside are pushed to the edges of the cell by the growing lump of unprocessed fat in the middle.

This, of course, slows down all liver processes – including the breakdown of that fat, so the problem gets rapidly worse. To make matters even worse, the swollen liver cells actually start to block the tiny bile ducts that wind through the liver, leading to a backlog of bile, which causes even more liver malfunction.

What are the symptoms of a fatty liver?

Typical symptoms include:

  • Loss of appetite – often complete anorexia. Whatever the underlying cause, with a fat, malfunctioning and painful liver, the cat doesn’t want to eat anything until their liver feels better. Unfortunately, the longer they go without food, the worse the liver gets…
  • Jaundice – caused by the backup of bile into the bloodstream.
  • Vomiting and diarrhoea.
  • Lethargy, weakness and ultimately collapse, as the liver begins to fail.
  • Muscle weakness and heart rhythm abnormalities as the cat’s electrolytes become unbalanced.

How is it diagnosed?

Although there isn’t one single blood test that diagnoses the condition, blood results showing liver damage and massively increased blood lipid levels are pretty much diagnostic!

Can it be treated?

Treatment involves intensive care nursing as an inpatient, intravenous fluid therapy, vitamin supplementation (liver malfunction can, for example, result in vitamin K deficiency and abnormal bleeding), and medications to reduce the symptoms (e.g. anti-sickness drugs if they are vomiting) and to improve liver function (e.g. SAMe and Silybin supplements). However, the most important component will be to get nutrition into the cat’s body so that their liver can deal with all that fat. As affected cats rarely want to eat, this is often done by a stomach tube.

While this may sound like very aggressive treatment, it can result in as many as 85% of affected cats surviving and making a good recovery. However, any delay in seeking veterinary advice may be fatal.

If you think your cat may have Fatty Liver Disease, please contact your vet immediately for advice!

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