Ron Hines DVM PhD
What Is Hepatic Lipidosis?
Hepatic lipidosis occurs when an abnormally high amount of fat (plasma lipids) accumulate in the cells of your cat’s liver. It occurs frequently because cats as a species have a harder time than most animals in shifting gears to live off of their fat reserves when they do not or cannot eat. When the fat in your cat’s liver builds up rather being turned into usable energy, your cat’s liver looses its ability perform its vital functions. Hepatic lipidosis is the most common form of liver disease in pampered, middle-aged domestic cats. It occurs most commonly in overweight cats. The underlying causes include obesity, intestinal issues such as IBD and triad disease, pancreatitis, a stressful home environment, inter-cat aggression, diabetes, and underlying cancer such as lymphoma.
Why cats are so prone to developing hepatic lipidosis remains unknown. Hepatic lipidosis is much less common in dogs.
Fatty liver disease can be fatal if it is not corrected quickly by your veterinarian. Although it can occur in cats of any age, veterinarians in the United States, Canada and Europe see it most often in middle-aged or older house cats. Some veterinarians observe that perhaps a few more female than male cats are affected.
Some still explain hepatic lipidosis in cats as something that simple occurs when a cat will not eat for any reason. But it is more complicated than that. The wild cats that gave rise to your domestic house cat and who still roam free in Europe and Asia loose almost a third of their body weight in winters when prey is scarce. But they do not develop hepatic lipidosis. My thoughts are that the large amount of wandering exercise required to find their prey and survive protects them. The fact that all reports find hepatic lipidosis more common in cats in the UK, Canada and the USA than in the less developed world adds to my suspicions that diet and lifestyle play a major role in this disease.
How Long Might It Take For Hepatic Lipidosis to Develop?
Most cats begin to develop signs of hepatic lipidosis within 3-7 days after they have stop eating . However that time period is variable. Those cats eating substantially less than their normal amounts of food but still eating a bit can take two weeks or so to develop the problem. The early signs are easily overlooked: decreased activity (lethargy), less interest in their surroundings, drooling (ptyalism), the beginnings of weight loss and gums paler than normal. But at that early stage of hepatic lipidosis, your cat’s blood bilirubin level is already rising as the cat’s liver struggles to process waste red blood cell hemoglobin. The cat’s blood ALT and ALP enzyme levels usually begin to rise as well.
You might notice that your cat is disheveled (not grooming itself like it should). You might notice that its eyes have mater at their nose-side corners (medial canthus) due to dehydration or that its third eyelids are slightly over extended and visible.
What Is Going On In My Cat’s Body?
When your cat doesn’t eat, its fat stores begin to mobilize (lipolysis) and their components, free fatty acids and triglycerides, are liberated into its bloodstream to take the place of the calories the cat is no longer getting from food. Some of those fatty acids are absorbed by its liver. Much of the rest is used as fuel by the cat’s muscles. In a normal liver, those fatty acids would be used to supply the large amounts of energy needed to perform the liver’s many vital functions. Those include processing absorbed nutrients, regulating blood sugar, eliminating toxic substances and manufacturing blood proteins.
But in cats (particularly fat, inactive Garfield cats), this fatty acid mobilization to the liver to produce its needed energy fails. The fatty acids do get there, but for reasons yet unknown they are not processed. Insulin resistance may play a part in that. The fats accumulate in the liver cells (hepatocytes) in their “triplet” triglyceride fat form swelling the hepatocytes to a point where vital cell functions are blocked. Love is blind. Many cat owners are so attached to their cherished cats that they are not very good at recognizing a potential health issue that is looming or won’t accept the notion that their cat is too chubby for its own good. ( read here & here) When I once attempted to diplomatically point out a weight issue to one of my cat-owning clients, her response was “yes, but he wears it well! “.
If My Cat Has Advanced Hepatic Lipidosis, What Signs Might I See?
Your cat will be much more obviously sick. If you look at the whites of its eyes (its sclera) they will usually have a slight to moderate yellowish tinge (jaundic). It will be lethargic. It will not eat. It often drinks much less than it should. It is quite likely that on occasion it will gag, vomit and drool. It may cease to defecate and if it does pass stools they may be dryer than normal due to dehydration and lowered intestinal motility although cats reaching hepatic lipidosis states because of underlying IBD or pancreatitis might present with diarrhea. It is likely for its gums to be pale due to anemia. That anemia is due to the accumulation of toxic products in its blood stream that suppress red blood cell formation (aplastic anemia). At typical pose is with its neck bent downward as in contemplation (ventroflexion).
What Tests Will My Vet Run And What Results Might Be Found That Help Confirm A Hepatic Lipidosis Diagnosis?
At your veterinarian’s clinic, your cats blood ALP level will most likely be quite high. That is because ALP enzyme has leaked out of its damaged liver cells. As I mentioned earlier, its blood bilirubin values will probably be above normal as well – almost certainly if it is jaundiced. ALT enzyme levels are usually high as well; but GGT, (another liver damage marker enzyme) levels are inconsistent (variable).
Your cat’s blood cholesterol level is likely to be high due to biliary stasis. Its blood ammonia levels is likely to be high because the livers of cats with hepatic lipidosis looses their ability to convert ammonia into less-toxic urea. (Blood ammonia levels are difficult to measure and rarely included in standard blood analysis panel. They are generally reserved for the diagnosis of suspected hepatic encephalopathy).
As I mentioned, many of these cats (about a third) are anemic (the non-regenerative form) because toxic products normally eliminated by the liver begin to interfere with the ability of their bone marrow to produce replacement red blood cells. A few become anemic due to bleeding tendencies that develop as their liver looses their ability to produce prothrombin and other blood clotting factors.
There are many severe diseases that cause alterations in a cat’s blood electrolytes. Hepatic lipidosis is one of them. Those electrolyte changes, when found, are not diagnostic of HL. But any major alterations in your cat’s blood electrolyte elements (ie sodium, potassium, calcium, magnesium , chloride, phosphate or carbonate) need to be corrected with intravenous fluids to help your cat recover.
An analysis of your cat’s urine might find that its ketone level is high. That often occurs when a cat is forced to utilize its stored fat for energy instead of utilizing the glucose that is normally stored as glycogen, in its liver. The nausea and weakness of ketoacidosis adds to your cat’s lack of interest in food.
Your veterinarian might elect to confirm the diagnosis of HL with an ultrasound-directed or fine needle liver biopsy/aspiration sent to a pathologist to rule out other forms of liver injury. That is particularly true so if some of your cat’s examination results are not compatible with hepatic lipidosis . Your vet might also use the ultrasound examination of your cat’s liver to confirm that the entire organ is involved. In other liver diseases, such as lymphoma tumors or abscesses, the pathology (damage) is patchy – limited to specific portions of the cat’s liver. In HL, the entire liver is involved.
Did HL Occur In My Cat Due To Some Underlying Health Issue?
I mentioned earlier that that is usually the case. Most veterinarians believe that there is always an underlying stressor(s) or disease process going on when HL occurs. For one, it is very difficult for scientists to produce hepatic lipidosis in cats that don’t have underlying health issues or a serious obesity problem. Even cutting a healthy cat’s food intake by 25-45% did not produce HL in one study. (ask me for for Laflamme2005)
In a few fortunate cats it was a change in its environment that your cat did not like and that can be corrected. Perhaps a new cat added to the house. Perhaps a stay at a boarding cattery, a pet “resort” or your Aunt Ida’s. Perhaps it was the new “All Vegan” diet that didn’t support its metabolism. Perhaps it was a bad reaction to a medication or some supplement you read about online. ( read here)
But more often, hepatic lipidosis is the end result of a chronic inflammatory problems affecting your cat’s digestive tract and the tract’s accessory organs, the pancreas, gall bladder, bile duct and liver. In older cats, the toxic byproducts of common feline cancers must also be considered. Viruses can also underlie the condition. (ask me for for Trotman2007) Underlying diabetes is occasionally the cause. No matter what the cause was, once hepatic lipidosis begins it appears to progress along the same biochemical and metabolic course no mater what originally caused it.
Cornell University once looked at 157 cats with hepatic lipidosis and examined their underlying issues. Twenty-eight percent had inflammatory bowel disease, 20% had some other underlying type of liver disease (usually cholangiohepatitis), 14% had cancer, 11% had pancreatitis, 5% had social problems (a new cat in the home, move to a new home, new family members, etc.), 4% had some kind of respiratory disease and 2% were diabetic.
Will My Cat Recover?
One should never attempt to treat a cat with hepatic lipidosis other than under the close supervision of a caring veterinarian. The survival of your cat will depend on the success of three things:
Enteral (tube) feeding – at least initially – is usually required.
Stabilizing or curing your cat’s underlying health problem(s).
When progress is made on all three fronts, about 80% of HL cats will recover. The younger your cat is at the time, the less overweight it is and the earlier in the disease that you presented it to your veterinarian, the greater its chance of recovery. The best ray of sunshine and likelihood of recovery is the beginning of a gradual drop in your cat’s blood bilirubin level and, of course, increased interest in food. Other blood values usually take longer to improve.
What Treatments Are Common For Hospitalized Cats?
Most cats suffering from hepatic lipidosis need to be hospitalized. Most are dehydrated and need to be rehydrated with intravenous and subcutaneously administered fluids. Other emergency stabilization procedures include bringing your cat’s body temperature back to normal and dealing with respiratory and circulatory issues in critical cases where the cat is rapidly deteriorating.
During that period, your vet will do a complete physical examination of your cat and almost certainly request a complete blood analysis. Depending on the hospital’s practice philosophy and blood work results, any number of equipment-assisted examinations to get a complete feel for the urgency and extent of the problem might be suggested. That could include x-rays, ultrasound exams, electrocardiograms and liver biopsies. It is entirely dependent on the veterinary hospital’s philosophy and the veterinarian that you choose. Any test that can be performed on a human can be performed on your cat. Corporate veterinary hospital chains, veterinary college clinics and animal hospitals in large well-to-do metropolitan areas are likely to be the most exuberant in suggesting them. Yet, with many years of experience behind them, it may take only a few moments for a seasoned veterinarian to size up the urgency and seriousness of the situation and devise the most successful way to treat it. Don’t underestimate the critical importance of a 24-hour loving and attentive veterinary nursing staff in providing successful outcomes.
In most cases cats will need a less stressful way to obtain nutrients than oral force-feeding from a syringe or spoon. That will mean inserting a feeding tube into its stomach and exiting somewhere else than its mouth. Depending on each cat and each cat owner’s temperaments, some cats can be released from the hospital and fed through that implanted feeding tube at home where cats are always more at ease. It will not nearly as drastic a technique as it will first appear to you when they bring your cat up front. That food is now getting to your cat’s stomach is critically important. But it is not sufficient to become relaxed. The cat’s general condition still need to be monitored closely for possible unexpected problems.
Veterinarians often give these cats antibiotics. An injectable form of vitamin K (phytonadione) might be included if a defective blood clotting process is present. Cats that are drooling and vomiting need medications to combat nausea. Those that are vomiting, need medications to calm and coat their stomachs as well. There are many. A commonly given one is Cerenia®.
Although I know of no studies that confirm its helpfulness in HL, there may also be a role for ursodeoxycholic acid supplements to help improve liver function. You can read more about that compound in another health issue here.
There are many more compounds veterinarians give to cats with hepatic lipidosis. None have been scientifically proven to work. But some might be helpful. We really do not know. They include: vitamins E, C and B12 , S-adenosyl-methionine (SAMe) and/or silymarin (Milk Thistle), L-carnitine and ursodiol. Providing the amino acids, leucine, isoleucine, valine and taurine has also been suggested. The optimal dose and dose frequency of all these products also unknown. Because most would not be approved by the FDA if marketed as liver medications, they are generally marketed as “liver support” products.
The Role Of Appetite Stimulants
There are medications that are known to increase appetite and, for many years, veterinarians gave them to cats with hepatic lipidosis in an attempt to encourage them to eat. Many have fallen out of favor – either because they had little effect, because they required a healthy liver to be effective, because of their sedative qualities or because their potential side effects were as serious as the disease itself. Mirtazapine (Remeron®) is probably the most common ones still given today and the one with the least undesirable side effects.
I placed a link at the top of this webpage to a newer appetite stimulant, capromorelin . It is an oral prescription product sold as Elura® and Entyce® by Elanco. Elura® is less concentrated than Entyce®. It is the one the Company suggests now for cats – although Entyce® had been used successfully in cats as well when it was the only form available. Capromorelin entered the veterinary market in 2018 with FDA approval for its use in dogs dogs and more recently in its less concentrated form for cats. It was originally developed for humans as a possible retardant of the frailties of old age.
Getting Back On Track With An Oral Diet
I have my veterinary nurses offer the sniff of a warmed premium canned cat food to cats hospitalized with hepatic lipidosis or other food reluctance issues every morning and evening. I want to know as soon as I can if they show any interest in the food or just turn their heads away. Bring some cans of your cat’s favorite food with you when you visit. Cats are creatures of habit. They might not like what’s in the clinic’s fridge. There are some cats that prefer dry. Be sure that the Staff knows if it is the case for your cat. Don’t be embarrassed to admit that your cat gets snacks of tuna, salmon, shrimp, sardines etc. at home. Any interest in food – even if it is to unbalanced snacks – is a very positive sign. That a cat that showed no inclination to eat now now does is a more accurate judge of progress than the results of any sophisticated tests. The change back to an oral diet needs to be gradual. Neither your veterinarians nor your cat would wish to remove an implanted feeding tube only to have to reinstall it.
Recovering cats are more likely to eat food presented to them on a small coffee cup saucer than in a deep bowl. Sometimes touching their nose with a finger that has touched the food gives them incentive to sample it. Forcing the food into the cat is never a good idea. If the cat does not eat the food within an hour, the food needs to go back into the frig for another trial later. It needs to be re-warm then.
The amount the cat’s stomach can hold can shrink considerably after a bout of hepatic lipidosis. Do not expect your cat to consume its normal amount of food. Instead, try small, frequent feeding. Allowing it to eat a large meal can result in vomiting. Some cats are very reluctant to resume eating in a hospital setting. Cats are very spatial – considerably more so than dogs. They like surroundings they are accustomed to – curling up on their favorite chair or sofa, hiding behind the curtain in a back room when they seek solitude. And they are generally quite hostile to cats that they do not include in their family group. “Cat Friendly” is at best, less Cat Unfriendly.
A practical way to judge anxiety in cats has not been discovered. A few cats externalize anxiety fears with their actions; but most cats internalize it. So you might ask to “borrow” your cat for a day or two at home to see if it is more relaxed and inclined to eat there. Be sure to check your favorite doctor’s work schedule and your work schedule for the week that is planned. Mondays and Saturdays can be very busy at animal hospitals. Sometimes, evening and weekend staff will not be familiar with the case. You do not want to end up with your pet at some after-hours emergency clinic if that can be avoided. Another good option, once your cat is eating again is a house call veterinarian to monitor the cat’s recovery.
Does What I Feed My Cat In The Future Matter?
What About Lifestyle Changes?
Both are important
I am always in favor of home cooking for your cat. That is best done with the assistance of a veterinary nutritionist such as the ones at Balance IT . Some veterinary school nutritionist will prepare a recipe for a fee. Others insist that your local veterinarian be the middle man.
Ask your local veterinarian what a good target weight would be for your cat. I don’t suggest any of the weight loss diets veterinarians sell. You don’t purchase your food from your physician. I don’t suggest the “fresh cat diets” sold from chillers at your local supermarket or PetsMart. Too many hands have touched the ingredients they contain. Let a certified veterinary nutritionist design the ingredients for a home prepared diet that will gradually reduce your cat’s weight. Then purchase only their vitamin mineral supplement and buy the food ingredients sold for humans at your local supermarket. Of course you will need to purchase an appropriate scale to weigh your cat periodically.
Spaying kittens too early in their life (before sexual maturity) has lifelong negative effects on their health – including increased risk of obesity. (read here)