Liz is a licensed veterinary medical technologist. She acquired a B.S. in veterinary medical technology from Lincoln Memorial University.
What Is Hepatic Lipidosis?
Hepatic lipidosis, or “fatty liver disease,” is a disease process characterized by excess fat accumulation in the liver. It is the most common form of liver disease seen in cats in North America and is still poorly understood. This disease can occur in cats of any age or breed and seems to affect females somewhat more than males. The common finding in almost all cats with this syndrome is that it occurs after two or more weeks of anorexia, but may also occur regardless. When an additional disease causes loss of appetite and precedes the condition, the hepatic lipidosis is defined as "secondary."
The terms "primary" or "idiopathic" hepatic lipidosis are used when another disease state cannot be identified, as is the case in approximately fifty percent of cats diagnosed. A state of obesity before the period of anorexia increases the risk of a cat developing this condition (overweight cats that lose too much weight too quickly). Numerous causes of anorexia can result in this condition, some of which including predisposing diseases, behavioral, and stress-related changes.
Causes and Contributing Factors
Some examples of possible contributions to the disease include diabetes mellitus, pancreatitis, cancer, owners going away, family members leaving or being introduced to the household, spending time in a kennel, changes in the pet population in the home, diet changes, and rapid weight loss. Once this disease process develops, it often becomes a rapid slippery slope; cats feel ill and will not eat, even if the initial cause for their loss of appetite was resolved. Once symptoms have begun, the disease process is already well underway. It becomes a vicious cycle; the longer the cat refrains from eating, the worse the hepatic lipidosis becomes, and vice versa. Without aggressive medical intervention, this cycle will lead to death in as many as ninety percent of affected cats.
The exact mechanism that causes hepatic lipidosis is not clear; the process is unique to cats in both severity and rate of occurrence. It is understood that as the anorexia continues, more and more fat is broken down throughout the body and that this fat is then transported to the liver. The liver should then process this fat and distribute it back to the rest of the body, but in cats developing hepatic lipidosis, this process is impaired, and fat begins accumulating in the liver. Damage to the liver usually occurs as a result of the liver cells being too swollen with fat to function properly.
The symptoms most commonly associated with this syndrome usually include loss of appetite, weight loss, lethargy, and jaundice. Owners occasionally notice behavioral or neurologic signs, such as excessive drooling, blindness, severe bloating, or seizures. These neurologic signs are caused by hepatic encephalopathy, a brain dysfunction as a result of liver disease. This condition is caused by toxins circulating to the brain that come from the abnormally functioning liver or by bacteria in the gut that are normally detoxified in the liver, such as ammonia. Ammonia is produced by bacteria in the gut from eaten proteins. This substance is detoxified in the normal liver, but when the liver fails to function normally, ammonia builds up in the bloodstream and causes the brain to dysfunction. If treated early enough, the changes in the brain may possibly be reversible.
The only way to reverse the process of fat accumulation in the liver is by feeding to supply the cat with its full caloric requirement. A number of ways exist to attempt to achieve this goal, but only a few are consistently successful. Trying different diets may induce a cat to eat in the initial phases of anorexia, but will most likely not induce a cat to eat once clinical signs of hepatic lipidosis develop. Force-feeding is ineffective as even with the most cooperative cat as it is virtually impossible to feed adequate amounts in this fashion. Cats also seem to rapidly develop aversions, and the association between food and the unpleasant forced experience might delay the return of normal eating habits. Appetite-stimulating medications may also work in the initial phase of anorexia, but are unlikely to consistently cause a cat to eat once symptoms develop.
When cats stop eating completely, the only viable option to reverse the disease process is tube feeding. The use of long-term tube feedings has changed the outcome in this disease from more than ninety percent mortality to less than thirty percent. Most cats require between one to three months of feeding through the tube. A commercially available, calorie-rich diet is used in most cases. The veterinarian will usually provide with the exact amount and feeding schedule modified to each patient's needs. Cats with hepatic encephalopathy may require a protein-restricted diet initially. The veterinarian may also include the addition of amino acids and vitamin supplements for the diet.
Frequent rechecks are required to assess the tube, the cat's overall health and quality of life, and repeat blood work to continuously assess liver function. Liver parameters found in the blood usually improve within two to eight weeks after initiating feeding. In cats with idiopathic hepatic lipidosis, recurrence is rare and most cats that recover go on to live normal lives.
- Brooks, Wendy. (2008). Hepatic lipidosis (fatty liver). The pet health library. Retrieved from http://www.veterinarypartner.com/Content.plx?A=1455
- Goldstein, Richard. (2008). Hepatic lipidosis in cats. American college of veterinary internal medicine.
- Personal experience.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
© 2018 Liz Hardin