Understanding Your Cat’s Liver Condition

1. Introduction

The liver plays a very important role in your cat’s health. An organ of complex structure and vital process execution, the liver is responsible for numerous metabolic functions including but not limited to detoxification of potential liver-damaging substances, synthesizing proteins and enzymes, and storing and utilizing nutrients in the form of glycogen. The condition of the liver is therefore responsible for maintaining a host of body functions that are vital to your cat’s health as well as deterring many very serious medical problems from occurring. Of course, a cat experiencing a health crisis requires immediate medical attention. Depending on the condition and its possible complications, the ramifications of liver conditions can be life-threatening; unfortunately, the prognosis for a cat with a significant liver condition is not ideal, and early detection with aggressive medical management is crucial.

The liver is the largest internal organ in the carnivore body, situated in the cranioventral abdomen between the diaphragm and the often visible pyloric portion of the stomach. Its primary lobes, the quadrate lobe, left lateral lobe, right division of the quadrate, and right medial lobe, are evident on physical exam. Liver function is interrelated with numerous other bodily systems and functions, and dysfunction can have sweeping effects on not only the regulation performed by the liver but any and all of the body parts and functions with which the liver interacts. In the natural course of living a cat’s life, however, the liver is a very forgiving organ, and in most cases, regardless of the causal agent, there is an amazing capacity for all of its diverse functions to return with supportive therapies that focus on easing the initial effects of liver failure while addressing what can frequently be an underlying insult to the organ. This varies widely depending on what exactly went wrong with the liver and what, if any, damage has occurred.

2. Common Liver Conditions in Cats

The liver is responsible for various metabolic processes, including detoxifying the blood and supporting digestion. It further produces proteins necessary for the body’s functioning and fat to be delivered to other tissues. Often, multiple organ systems are affected by liver disease, which may present in conjunction with gastrointestinal, immune system, pancreas, and metabolic changes. It is important to make the connection between all of these systems since it affects the cat’s response to therapy and the overall prognosis.

Hepatic lipidosis is the most common liver condition in cats. It generally presents in obese patients with clinical signs of decreased appetite for a few weeks or more, vomiting, and yellowing of the skin or whites of the eyes. Hepatic lipidosis may be more common in multi-cat households. The specific cause of hepatic lipidosis is unknown, but it is related to stress causing the liver to stop processing fat normally, converting it to an unusable, toxic form of fat. Both leanness and underweight status increase the risk for developing hepatic lipidosis, thus declining liver function, and increased fasting ammonia is suggestive of progressive liver disease or hepatic encephalopathy in this feline group. Additionally, hepsin proteins are specifically released by feline hepatic cells, making quantifying levels of these markers an intuitive non-invasive diagnostic tool to recognize and monitor feline non-alcoholic fatty liver disease.

2.1. Hepatic Lipidosis

When a cat is fat, the liver's metabolic and transport systems are decreased, and the liver's primary function to detoxify the blood is overwhelmed. As fat accumulates in the hepatocytes, the liver loses its capacity to function properly. The liver cells, as a result, become less capable of clearing wear and tear substances from the body. Signs of Hepatic Lipidosis Most cats with hepatic lipidosis are jaundiced. They frequently have a very low appetite, are lethargic, vomit intermittently, and have diarrhea. Most of these animals have been overweight and either have a stressful occurrence in their life history or live in multi-cat households at their inception. Diagnosis Hepatic lipidosis is usually seen in obese cats who have been starving long enough, although it can be seen in other cats under the perfect amount of stress. Diagnosis is made through blood tests and an ultrasound or radiographs revealing "hyperechoic" liver. It can be verified through a needle biopsy. The treatment for this condition is slow refeeding alone or hospitalization with a feeding tube and force-feeding. Some cases will not respond if normal food is offered because of nausea or ulceration, requiring that the nutrition be provided through the tube until the final feeding by mouth. Prognosis Poor if left untreated or treated early, but excellent for cats that stop eating for a few days. Call immediately if your feline friend stops eating.

2.2. Hepatitis

Hepatitis (inflammation of the liver) can affect cats. This condition may arise suddenly (acute hepatitis) or develop more slowly, possibly over many months or longer, and persist for a long time or for the remainder of the cat’s life (chronic hepatitis). It might be very severe (fulminant hepatitis) or mild, although most cats with hepatitis show at least some signs of liver failure. There is infectious hepatitis of cats and non-infectious hepatitis. Cats sometimes suffer from two different forms of chronic hepatitis: cholangiohepatitis, which primarily affects the bile ducts of the liver, and lymphocytic portal hepatitis (LPH), which primarily affects the veins of the liver. Many cases of hepatitis in cats are unexplained, so-called idiopathic hepatitis; however, a variety of causes for hepatitis in cats have been determined, particularly in young cats, resulting in acute or subacute hepatitis (lasting for a month or less), including infections by viruses and bacteria, and exposure to certain bacteria or the ingestion of specific drugs. In contrast, one of the most common causes of chronic hepatitis in cats in most parts of the world is liver fluke infection.

Cats with acute or chronic liver disease commonly have some domains in common, including lethargy and a loss of appetite for food. Some cats are very nauseated and might vomit a lot. There might be right-sided abdominal pain and an aversion to being touched, and urinary or other behavior might change. A more or less yellow tinge to the skin and especially the white of the eyes (jaundice) results when massive numbers of hepatic cells are broken, leading to abdominal or full-body swelling, possibly bleeding, and/or difficulty in blood clotting. Ascites and possible hemorrhages, jaundice, and signs of hepatic encephalopathy are more indicative of chronic liver failure, while vomiting, abdominal pain, and/or jaundice indicate hepatic inflammation.

Mouth ulcers and a poor fur coat are generally indicative of chronic hepatitis.

Many viruses and some bacteria may also inflame the liver, so they may be added to the list, as could liver tumors, pancreatitis, and other forms of inflammation that secondarily affect the liver. The ideal approach to accurately understanding liver disease is to undertake a liver biopsy, but this is not always feasible in general veterinary clinics. Stress by itself is capable of substantially elevating bile acids and pancreatic enzymes in cats with liver disease, so these tests are used to help spot cholecystitis, which more regularly characterizes either acute flare-ups of cholangiohepatitis or pure cholangitis. In just the same way, fine needle aspiration in the liver is not exceedingly sensitive for the identification of small tumors and does not distinguish hepatocellular carcinoma from adenoma. In addition, differences could occur and should be detected in liver lactate or ammonia concentration, in both of which the results shall be higher in portal-blood hepatitis caused by disease of the supplying hepatic vein blood.

2.3. Cholangiohepatitis

Liver and bile duct cells can become inflamed, and a sequence of changes will result in reversible and sometimes permanent liver damage, which is a progressive and life-threatening condition. These changes arise because bacteria cause infection and irritation in the bile duct; also, there are certain bacteria that can enter the bloodstream and damage the liver. There are also a large number of immune-mediated liver diseases that result in cats with both bile duct inflammation and liver cell injury. These diseases are often inflammatory bowel diseases. When inflammation is present in the bile ducts as well as in the liver, it is known as cholangiohepatitis. Bile, produced in the liver, helps the gut break down the fat in food, and the liver is constantly communicating with the gut; this is why, in cats, all the different liver diseases can sometimes closely resemble the individually rare but inflammatory bowel-related causes of cholangiohepatitis.

Symptoms of cholangiohepatitis can include fever, jaundice, depression/lethargy, weight loss, and abdominal pain and fluid retention. Because inflammation in the small bile ducts can lead to progressive scarring and narrowing of the ducts, leading to the progressive backup of toxins like copper and bile acids into the liver, the main way to help your cat is to ideally diagnose the problem early before permanent scarring of the liver begins to occur. The earlier the problem is seen, the better, though the ability to treat the condition can be difficult depending on the severity of the condition and associated changes in the liver. The diagnosis of cholangiohepatitis is usually made with the help of an ultrasound based on the changes that are found within the liver and bile ducts. A liver tissue fine needle aspirate, which removes some of the affected tissue for diagnostic purposes, or a bile aspirate or a bile culture may also help in the diagnosis. The only absolute way to diagnose the condition is through a surgical biopsy, which is rarely performed. Treatments used most often include antibiotics and supportive care. The severity of cholangiohepatitis can differ greatly; some cases can be cured, and some cases can succumb very quickly and suddenly to the liver failure that results. Most cats with cholangiohepatitis would benefit from a veterinarian if a specific veterinarian were available to see them.

3. Symptoms and Diagnosis

Symptoms will typically vary depending on the severity and type of liver condition; however, the following signs of illness can be indicative of a potential liver disorder and will suggest the need for further investigations. Fatigue can indicate your pet is feeling unwell and, typically, cats will prefer to 'hide' if they are not feeling well in a bid to avoid being spotted by potential threats. You may notice your cat showing signs of vomiting or nausea, which can range from occasional vomiting to more severe and regular vomiting. Further signs of liver disorders include a reduction in appetite, leading to weight loss and increased drinking and urinating, which can be connected to liver disease. Ammonia, a by-product of protein metabolism, is typically converted into urea when the liver is healthy; however, in the case of many liver diseases, the liver detoxification pathways are affected, which can lead to a build-up of ammonia in the blood, resulting in neurological alterations and depression. If jaundice is present in an animal, it indicates that the animal's liver is not functioning correctly. Jaundice occurs when bilirubin, the orange-yellow pigment in the bile, is no longer removed from the bloodstream and builds up in the body; they will report having yellow eyes and mucous membranes. If you observe any of these signs, we recommend contacting a veterinarian to further investigate whether they are connected to a liver disorder. Diagnosis of a liver disorder will typically combine a detailed history of your pet, a full clinical examination, blood and urine testing, ultrasound scanning, and liver biopsy. A range of blood tests helps us assess the health and performance of the liver, along with the ability to look for markers of any other concurrent diseases or conditions. Expanding on this, an abdominal ultrasonographic examination will evaluate liver size and assess internal structure and the presence of any masses or obstructions to liver drainage. A liver biopsy is typically performed over the weekend or as soon as possible to allow the laboratory to analyze and report the samples collected. Our veterinarians will provide a comprehensive examination of your pet and discuss relevant diagnostic tests that may be required. An inpatient hospital admission may be necessary and, in general, the process from initial consultation to diagnosis will take a minimum of 24-48 hours; however, depending on the case, this may be extended. Upon completion, we will have a definitive diagnosis and can proceed to discuss an appropriate treatment plan, prognosis for your pet, long-term management of the disease, and any necessary monitoring.

4. Treatment Options

Treating liver conditions in cats varies significantly, depending on the underlying cause and severity of the disease. In some instances, dietary changes are warranted; in others, cats may need to take multiple medications to control their disease. Rarely, cats have liver conditions so severe that the only way to return them to close-to-normal liver function is through surgical intervention or even a liver transplant. For more minor liver concerns or organ support, the following treatments may be in order:
- Vitamin A
- L-carnitine
- Adenosylmethionine
- Contains S-adenosylmethionine
- Contains ursodeoxycholic acid
- Denamarin

5. Preventive Measures and Diet

- Easier to digest diet that is moderate in high-quality proteins and lower in fat

Your veterinarian will lay out a treatment plan that is in your pet’s very best interest. The course of action that is decided between you, as the owner of the cat, and your veterinarian will largely rely on your pet’s overall health, as well as the severity of liver disease in your cat. No matter the cause of the disease, it’s important to closely monitor the liver. Over time, this disease can lead to scar tissue formation as the liver tries to regenerate new tissue. This scar tissue can lead to what is often called cirrhosis, a deadly condition.

In the case of infectious liver diseases, there are possible long-term side effects that must be monitored via follow-up appointments. These complications are different from the side effects that may be noted from medications used to treat the original condition to begin with. In addition to side effects and reactions, it’s possible that the liver condition will worsen. For cats newly on medication, tests will be performed to ensure that these intended side effects are indeed happening.

To maintain liver health, providing a balanced diet is the key to preventing a variety of liver diseases in cats. Proper nutrients are essential for the physiological functioning of the liver, and different liver conditions require different nutritional modifications. Overfeeding can contribute to hepatic lipidosis secondary to obesity. Silver cat breeds have a higher prevalence of hepatic lipidosis than other colors because of their higher body fat content. Low-carbohydrate, high-protein diets can help control body weight and prevent hepatic lipidosis. Fresh water should be available to all cats to prevent chronic dehydration, which can contribute to steatohepatitis.

A healthy liver serves as a storehouse for several important nutrients, including glycogen, vitamin B12, vitamin K, lipotropic factors, and copper. A well-balanced diet, tailored to your cat's age, lifestyle, and any diseases it may have, is essential for optimal liver function. High-quality proteins include animal products that can be easily metabolized into amino acids; they also provide energy and are an essential component of the cat's body. Provide branched-chain amino acids that form 50 to 70% of the ornithine cycle in the liver and help the liver function properly. To help provide energy to the liver, fats can be included in a cat's diet. Use medium-chain fatty acids because they are easier to metabolize than long-chain fatty acids, which can accumulate in an impaired liver. Provide vitamins, minerals, and other nutrients to the liver in a readily absorbable form. Supplements such as zinc, copper, selenium, vitamin B complex, vitamin E, and vitamin C can support liver health. Commercially available prescription cat food may contain a combination of these ingredients, so follow the feeding instructions carefully to ensure your cat receives the correct amount. Generally, high-quality feline nutrition is beneficial for your cat's liver. Unrealistic consumer products should be avoided.

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