This article aims to explain the details of hepatic lipidosis in cats, a common and serious issue also known as fatty liver disease. The aim of this article is to provide a simple, clear explanation about hepatic lipidosis for cat owners. The condition is unique to cats: it is not seen in other small animals.
What Is Hepatic Lipidosis?
Hepatic lipidosis is a type of liver disease where the liver tissue is flooded with fat (lipid) which has been rapidly mobilised from the fat stores. The fat, along with metabolic byproducts of its processing, prevent the liver from functioning normally, leading to liver failure.
It’s a disease that most often affects obese cats that have recently lost weight: if such cats become visibly unwell, this condition should be high on the list of possibilities.
How Common Is Hepatic Lipidosis?
Hepatic lipidosis is probably the most common type of liver disease seen by vets. Middle-aged cats are most often affected but it can happen in cats at any age. All cats can be affected: there is no breed predisposition.
Symptoms of Hepatic Lipidosis in Cats
This disease is most often seen in overweight or obese cats that have stopped eating (or are eating significantly less than before) and that have suddenly lost weight.
The most common clinical signs noticed by owners include:
- Inappetence or anorexia
- Weight loss with muscle wasting
- Lethargy and dullness
- Weakness, unable to exercise and jump as usual
- Vomiting and diarrhea
- Jaundice, with yellowing of the gums and the whites of the eyes
- Behavioral changes: Cats are just “not themselves”.
What Causes Hepatic Lipidosis?
The precise mechanism behind hepatic lipidosis is unclear: sometimes it seems to be idiopathic (i.e. the cause cannot be determined) while in other cases it happens secondary to some other primary disease.
The most common sequence of events seems to be that a cat which has significant fat reserves (i.e. overweight or obese) suffers from an underlying disease which causes them to stop eating. Their body then mobilises large amounts of fat (triglycerides) from body reserves, and the liver is flooded with more fat than it can cope with, leading to hepatic lipidosis.
Typical examples of primary causes which contribute to the problem starting include:
- Obesity, followed by weight loss
- Anorexia for any reason
- Sudden changes in the diet
- Nutritional deficiencies
- Hormonal diseases including diabetes mellitus and hyperthyroidism
- Other concurrent illnesses such as kidney disease, pancreatitis (inflammation of the pancreas), inflammatory bowel disease, and/or cholangiohepatitis (gall bladder disease)
- Any condition or situation which leads to the cat losing their appetite and stopping eating
Diagnosis of Hepatic Lipidosis
If your DVM veterinarian suspects that your cat may have hepatic lipidosis, the following steps may be taken.
1. Detailed History Taking
Your vet will discuss every aspect of your cat’s condition and overall health care. A dietary history is important: what sort of food does your cat eat? Has a new food been started recently? Are they being fed any supplements?
Are there any other factors that could be affecting their appetite? Is the cat urinating and defecating normally?
There are other causes of the same types of signs as hepatic lipidosis, and this history will help to differentiate the various possible causes. Liver failure can lead to a condition known as hepatic encephalopathy, with behavioral changes linked to the accumulation of toxins that affect the brain, so an owner’s reports of how a cat behaves can be very important.
2. Physical Examination
Your veterinarian will check your cat over carefully, checking for the signs of hepatic lipidosis listed above. The examination will normally include taking the cat’s temperature, listening to their chest with a stethoscope, palpating the abdomen carefully, and weighing the cat, comparing with previously recorded body weights.
3. Routine Blood Tests
It’s very likely that your veterinarian may carry out blood work, including the usual panel of diagnostic tests, such as hematology (blood count) and biochemistry profiles. Typical abnormalities seen include:
- some elevated liver enzymes (ALT and ALKP) while another liver enzyme (GGT) may be normal or even low.
- Bilirubin levels are often elevated.
- Anemia may be identified.
- Electrolytes may have altered levels, including reduced potassium concentrations, which can aggravate the lack of appetite and dullness.
Simple urine tests will also be carried out.
This type of work up is known as the Minimum Database, and it’s carried out to review most sick cats, regardless of the signs of illness.
4. Specialised Blood Tests
5. Diagnostic Imaging
Radiographs (x-rays) may be taken, and an ultrasound scan will probably be needed. On ultrasound, the liver appears hyperechoic (denser) compared to the kidneys (a normal liver has the same echogenicity as the kidneys). This finding is described as diffuse hyperechoic hepatopathy, and along with the history and clinical signs, it’s sufficient to make a provisional diagnosis of hepatic lipidosis.
To make a definitive diagnosis, a liver biopsy is needed.
- Fine needle aspiration of the liver (FNA) is the most common method used: this can often be done in a conscious cat in the consulting room. This allows a small number of liver cells (hepatocytes) to be collected, placed on a microscope slide and sent to the laboratory.
- If a cat will not tolerate this, sedation or anaesthesia may be used, and a full biopsy may be taken from the liver, guided by ultrasound. There may be concerns about a cat’s blood clotting ability if this method is being considered, as clotting issues often accompany liver disease, and the bigger sample needed compared to FNA means that there is a higher risk of bleeding.
Biopsy samples, however they are collected, are sent to an external laboratory, and the diagnosis is usually made from the pathologist’s report. Findings typically include vacuolated cytoplasm in hepatocytes suggestive of lipid accumulation, resulting in so-called “vacuolar hepatopathy”.
Usually lipidosis is graded as mild, moderate, marked, or severe, and this is a useful guide to the prognosis for an individual cat.
Treatment of Hepatic Lipidosis
Hepatic lipidosis is a serious, life-threatening problem requiring intensive treatment, and a stay in your local veterinary hospital, is always needed.
Treatment has two main aspects
Therapy To Treat Liver Failure
Initially intravenous fluids are necessary to rehydrate cats that have become dehydrated because of the lack of food and drink, combined with the metabolic changes caused by the disease process.
General liver-supportive medication is also given, including:
- Ursodeoxycholic acid to alter the composition of bile so that it is less toxic or irritant.
- S-adenosyl-L-methionine (SAMe) – a specific anti-oxidant supplement that supports liver function
- L-Carnitine – a nutritional supplement that assists with fat transport in the body.
- Essential fatty acid supplementation may be recommended
- Taurine – this is an essential amino acid that’s usually deficient in anorexic cats. It makes sense to give cats a supplement of this until they are eating normally again
- Vitamin B-12 (cobalamine) – a vitamin that supports liver function
- Vitamin K – many cats with hepatic lipidosis have inadequate blood clotting ability due to the fact that the liver is not able to continue to maintain normal levels of blood clotting factors
- Antibiotics are often recommended to deal with secondary bacterial infection
- Appetite stimulants, to encourage the cat to start eating again
Nutritional Therapy To Move the Cat From Food Aversion Back to a Normal Eating Regime
Affected cats need to start eating nutritious food again, and this can be difficult because anorexia is one of the signs of the disease.
Feeding tubes are usually placed to allow force-feeding to take place.
Typically, a veterinary recovery diet is given through the feeding tube for the entire recovery period, which could be as long as 8–16 weeks.
Generally, these cats require 7–10 days of hospitalization to allow this type of refeeding to be started, and for quantities of food fed to be gradually increased until they are being fed enough every day to sustain them properly.
Cats are then often sent home, where they are given a daily amount of tube feeding that’s enough to sustain their long term health.
Pet owners start off with tube feeding, but will soon start to offer normal food as well, and a gradual process of changing from tube feeding to normal eating can take several weeks and after that, careful attention to monitoring food intake needs to continue for a further period.
What Types of Feeding Tubes Are Used?
There are three main types of tubes that may be used
- Nasal tubes: either nasogastric (NG) or naso-esophageal (NE). These are much narrower, and while helpful for hospital use, they cannot easily be used by owners at home.
- Esophagostomy tubes, that enter via a surgical wound on the side of the cat’s throat directly into the esophagus
- Gastrostomy tubes, that enter the stomach directly via a surgical wound on the cat’s side.
Monitoring and Prognosis
As well as frequent physical rechecks, repeated blood samples may be taken to monitor the changes in liver function. Around 90% of cats make a full recovery from hepatic lipidosis, but the outcome depends on the severity of hepatic lipidosis, the overall underlying health of the patient and the commitment of the owner to detailed follow up nutritional support. This is a deep-seated condition that takes a long time for recovery: two to four months of careful care at home is needed.
Hepatic lipidosis is a serious liver disease that typically affects obese cats that have recently lost a significant amount of weight. If this is suspected, urgent and intensive veterinary care is critically important.
Frequently Asked Questions:
How long can cats live with hepatic lipidosis?
This condition is frequently fatal if not treated aggressively, with affected cats dying within days or weeks. Intensive veterinary care is needed, with careful follow up care at home for up to four months.
How is feline hepatic lipidosis treated?
Treatment involves a combination of detailed nutritional support (e.g. with feeding tubes installed by the vet) and a spectrum of specific support medications for liver failure.
What do you feed a cat with hepatic lipidosis?
Your vet will advise you on what to feed, but in general, a highly digestible, high carbohydrate diet that is very palatable is needed. A liquified form will be needed for the phase when the cat is being fed through a feeding tube.
What are the signs of liver failure in cats?
The most common signs are inappetence or anorexia, weight loss, lethargy and dullness, vomiting and diarrhea, and often jaundice (yellowing of the gums and the whites of the eyes).
How much does it cost to treat a cat with hepatic lipidosis?
It is impossible to estimate this cost, as there are so many possible factors going on in the background of individual cases. You should ask your veterinarian for a detailed estimate before agreeing to proceed with treatment. Costs could vary from $1000 for a simple case to $8000 or more for an exceptionally complex case of hepatic lipidosis.
How serious is hepatic lipidosis in cats?
This is a very serious and life threatening disease, requiring urgent and comprehensive veterinary treatment.