Whether you are a seasoned cat-lover and owner or you are relatively new to owning a vivacious feline, knowing the signs of serious disease in cats is important in order to prevent irreparable damage or even death. The trouble with most animals is that they are very stoic in nature, meaning that they often do not express that they are in physical pain very openly. Cats are no different in this regard. Therefore, when it comes to diseases such as feline hepatic lipidosis (“FHL”, or “fatty liver” in non-medical terms) determining what and when problems started can be difficult. With FHL, oftentimes owners will only notice a severe problem with their cat when the damage is too far gone from repairing. If this does or has happened to you in the past, don’t feel like you are an awful owner, because the truth is that the cause of this disease is actually largely unknown. Sure, there are a handful of pretty consistent predispositions that tend to point to contributing to causing FHL, but there is no one mechanism of action or culprit to be wary of. With that being said, let’s take a look at what FHL is exactly, how it is caused, why it is caused, the most common predisposing factors and what signs are indicative of this disease.
Feline hepatic lipidosis is a form of liver disease occurs because of nutritional, metabolic or toxicity defects. Despite whatever the cause may be, when a cat stops eating, their body shifts from using food for energy and instead starts to metabolize fats. The feline liver was not designed to deal well with this. Thinking back to a cat’s wild ancestors, they derived their complete nutritional profile from eating entire animal carcasses. Animal tissue is mostly comprised of protein, some carbohydrates, some fats, water, and all of their essential vitamins and minerals. It was never an evolutionary necessity for cats to be able to handle fat as their main source of metabolizable energy. Therefore, when a domestic cat enters a state of starvation and their bodies do not have any more readily available glucose from carbohydrates to utilize, they will shift their metabolism to using up fat stores for energy. The feline liver is not very good at processing fat, and within a short period of time it will become overwhelmed with the task and the liver cells become filled with fat and becomes unable to function properly. This disease can have a rapid onset and the severity of the progression of the disease will determine if there is any chance at reversing the process or if there is no chance of recovery.
It would be wonderful if there were a strict set of guidelines we could lay out for our readers to help them steer clear of FHL, but the truth of the matter is that the exact cause of this disease is largely unknown. The main link to FHL is obesity in cats. Now, whether or not you’re afraid of your cat having FHL, obesity in cats is something you want to steer clear of regardless (you can read our other posts on feline obesity and why it is so detrimental to them living a, long, healthy, and pain-free life, and how to slim down your cat if they are a little on the chubby side). However, the reason as to why obese cats present to vets with FHL more often than non-obese cats is unclear. Because this link is poorly understood, what you will benefit from knowing is what to look out for in your cats behaviour, appearance and eating habits.
What is really important for cat owners to know is that before your cat develops FHL, they will go through a bout of not eating for a significant period of time (this is when the body runs out of glucose as a fuel source and begins to use fat as an energy source instead). So what are the triggers for anorexia in cats? The most common causes are separation anxiety, moving, boarding at a kennel or hospital, or pancreatitis (inflammation of the pancreas, which can be caused due to a whole plethora of reasons, which will probably be discussed in more detail in another post). All of these stressors cause inappetance in the cat. You should also be on the look out for vomiting and lethargy. Unfortunately, some owners do not take their cat in to see a vet when these initial symptoms are presented, and the later stages of this disease can bring about additional weight loss, jaundice (yellowing of the eye membranes, gums and ears is most prominently noticed), seizures, drooling and comas. The time at which your cat is seen by a veterinarian and diagnosed with FHL is critical in determining if the damage done to the cells of liver can be reversed.
When a cat is presented to a veterinarian with concerns over their inappetance, there is potential that the liver is not so damaged and the cat may recover given the right treatment. Stimulating the cat’s appetite or even force-feeding the cat is the first attempt at shifting the cat’s body from using fat as a fuel source to using food instead. The first attempt at getting a cat to eat is to feed cat food in the equivalent of human “junk food” (fancy feast, whiskas, etc) or wet food that is high in delicious fats (such as Medi Cal’s Recovery or Prescription Hill’s a/d). If this does not work, more drastic measures may need to be taken, such as inserting a feeding tube into the throat of the cat (done under anesthesia) to directly shuttle food into the stomach. Over time, the body will shift it’s focus back into digesting and utilizing energy from their diet instead of trying to gain energy from fat.
Unfortunately, cats that are presented with severe symptoms of FHL may not be so lucky to recover. Due to mechanisms that are highly complicated and largely unknown, cats in the late stages of FHL often die or need to be put down due to liver insufficiency. By reading this post you have already made yourself more aware of the signs and symptoms of FHL and when not to take a chance on your cat’s well-being. Call your veterinarian and make an appointment to speak about your concerns if your cat is obese, has been exhibiting signs of anorexia, or you think may have another underlying disease such as pancreatitis which could contribute to a lack of appetite.