Hepatic Lipidosis in Cats

Hepatic Lipidosis in Cats

by Arnold Plotnick MS, DVM, ACVIM, ABVP

Section: Overview

Hepatic lipidosis (fatty liver disease) is a syndrome characterized by an accumulation of excessive amounts of lipid (fat) within the cells of the liver, abnormal bile flow within the liver, and impaired liver function. Severe impairment of liver function may affect the liver's ability to detoxify the blood. As toxins accumulate, they can affect the mental status of the cat, leading to mental dullness, severe depression, and seizures. Hepatic lipidosis can occur as a primary event, or it can occur secondary to other disease processes, such as diabetes. It is the most common liver disease encountered in cats.

Adult cats of either sex can be affected. Any breed of cat is susceptible. Middle aged to older cats are most likely to be affected.

Hepatic lipidosis can be a serious disease. Even with aggressive therapy, a significant number of cats die from the condition.

The cause of hepatic lipidosis remains unknown. Obesity is thought to be a predisposing factor, as most (but not all) affected cats are obese at the time of disease onset. A period of anorexia (decreased appetite), occurring as a result of a stressful event (such as the addition of a new pet or family member, or a sudden change to a less palatable diet) can trigger the onset of hepatic lipidosis.

What To Watch For

Anorexia
Loss of muscle mass
Vomiting
Drooling
Jaundice (yellow tint to the whites of the eyes and possibly the skin inside the ears)
Severe depression
Possible seizures

Diagnostic Tests

The diagnostic tests needed to confirm the presence of hepatic lipidosis and exclude other liver disorders include:

Complete medical history and physical exam. This includes examination of the gums, whites of the eyes, and other part of the body for jaundice (yellow discoloration).

Blood tests and urine analysis to confirm that the liver is affected

Bile acid test to assess how well the liver is functioning

Abdominal x-rays to evaluate the liver

Abdominal ultrasound. This is a painless procedure in which a probe is held against the abdomen and is used to detect valuable information about the health of the liver.

Fine-needle aspirate of the liver. This technique allows for a small sample of liver cells to be obtained and evaluated.

Liver biopsy. Obtaining a biopsy specimen (a small piece of the liver) is the definitive test for making a diagnosis of hepatic lipidosis.

Treatment

Dietary therapy is the mainstay of treatment. Affected cats may need to be force fed, or fed through a tube in the nose, esophagus, or stomach. Hospitalization is usually required for the first few days. Treatment for hepatic lipidosis may also include some or all of the following:

Medication to control vomiting

Drugs that help control gastrointestinal bleeding for cats that develop stomach ulcers

Medications that help control the mental signs of hepatic lipidosis in severe cases

Blood transfusion if the impaired liver cannot normally regulate blood clotting

Appetite stimulants

Drugs to improve bile flow within the liver

Home Care and Prevention

Follow all feeding instructions very carefully, as dietary therapy is the most important aspect of therapy.

If a nasal, esophageal, or stomach feeding tube has been inserted, follow all instructions as to the care and maintenance of this tube, and report any problems to your veterinarian immediately.

Give all medications and dietary supplements as directed.

Although the actual cause of the disorder is unknown, obesity and anorexia have been noted to be associated with the onset of disease. Therefore avoid overfeeding your cat to prevent obesity and avoid stressful situations that may cause a cat to suddenly stop eating, such as the addition of a new pet or family member, or suddenly changing your cat's diet.

Section: Information In-depth

Hepatic lipidosis (fatty liver disease) is a common disease of the feline liver in which abnormally large amounts of lipid (fat) accumulates within the cells of the liver. In other animals (humans, dogs, laboratory animals), lipid accumulation tends to be harmless, however, the cat's unique pathways of protein and fat metabolism cause lipid accumulation in the liver to have severe consequences. Any breed of cat may be affected, and both sexes seem to be affected equally. Middle aged to older cats are more susceptible than young cats.

Most, but not all, affected cats have a history of being obese, as well as a history of a sudden loss of appetite, often precipitated by a stressful event, such as a move to a new home, separation from an owner, a new pet or family member in the household, or a sudden switch to an unpalatable food. Anorexia, depression, and intermittent vomiting are the first signs usually noted by the cat owner. As liver function worsens, cats may develop jaundice (a yellow discoloration to the whites of the eyes, gums, and skin), severe loss of muscle mass, drooling, and signs of mental dysfunction (severe depression, sudden blindness, seizures). Cats often lose at least 25 percent of their body weight. The diagnostic tests recommended will help differentiate hepatic lipidosis from other liver diseases such as:

Cholangiohepatitis - an infection or inflammation of the liver and bile ducts

Feline infectious peritonitis - a deadly viral disease that can affect many organs, including the liver

Toxic liver disease - caused by ingestion of a drug or other harmful toxin

Liver cancer

Feline leukemia virus

Parasites - such as liver flukes (uncommon)

Section: Veterinary Care In-depth

Veterinary care should include diagnostic tests and subsequent treatment recommendations.

Diagnosis In-depth

There are a variety of diagnostic tests that may be run so that a diagnosis of hepatic lipidosis can be made. These tests may include:

Medical history review and complete physical exam. A history of obesity and sudden onset of anorexia after a stressful event is a classic finding in hepatic lipidosis. Physical exam usually reveals dehydration, severe weight loss, drooling and jaundice.

A complete blood count usually reveals mild anemia, and abnormally shaped red blood cells (known as poikilocytes), which are often an indicator of liver disease.

Blood tests that test organ function are especially important. Cats will usually have moderate to severe elevations of several liver parameters. A thyroid test is necessary to rule out a hyperactive thyroid as a cause of the liver enzyme elevations.

A bile acid test is a special blood test that may be necessary. It requires a blood sample after a 12 hour fast. The cat is then fed (force fed, if necessary), and another blood sample is taken two hours later. This simple test assesses the function of the liver.

Analysis of the urine may give information concerning the function of the liver.

X-rays of the abdomen allows assessment of the size and shape of the liver, and may help rule out a tumor as a cause of the liver problems.

Ultrasound of the abdomen allows limited assessment of the internal structure of the liver. It allows some assessment of the gall bladder and biliary system, and may rule out cancer as a cause of the liver disease. It may also help provide a method for obtaining a biopsy sample.

A fine-needle aspirate of the liver is a small sample of liver cells that are obtained by inserting a needle into the liver. This technique requires no or minimal sedation, and complications are extremely rare. Results must be interpreted cautiously, however, because concurrent liver diseases cannot be ruled out and may be missed.

A liver biopsy, in which a small sample of liver tissue is obtained, is the definitive test for diagnosing hepatic lipidosis. A biopsy specimen may be obtained surgically, or may be obtained using a special instrument that is inserted into the abdomen while being guided by the ultrasound probe. Surgical biopsies can be obtained by most veterinarians. Ultrasound-guided biopsies are often referral procedures.

Therapy In-depth

Therapy for hepatic lipidosis is aimed at reversing the accumulation of fat in the liver, and treating the signs of liver dysfunction. The primary treatment for reversing the fat accumulation is aggressive nutritional support.

Dietary therapy is the mainstay of treatment. High protein diets are usually recommended (except in cases where the cat is showing mental signs of liver disease). Because nearly all affected cats are completely anorectic, food is administered through a nasal, esophageal, or stomach tube. This requires hospitalization, and sedation or anesthesia.

Several dietary supplements such as carnitine or arginine may be beneficial in treating cats with hepatic lipidosis, and may be recommended or prescribed by your veterinarian.

Vomiting is a frequent finding in cats with hepatic lipidosis. Many cats require a medication to help control vomiting, such as metoclopramide, especially during the initial 1 or 2 weeks of tube feeding.

Some cats with liver disease develop ulcers and subsequent gastrointestinal bleeding. Drugs that control gastric acidity, such as Tagamet, Zantac or Pepcid, may be necessary to help control this. Carafate, a gastric protectant, may be used in conjunction with the antacids.

Antibiotics may be necessary in severe cases. They help kill off bacteria that produce harmful toxins that may lead to various mental manifestations of liver disease (drooling, depression, blindness, seizures).

Blood transfusions may be needed if the liver is so impaired that it cannot produce adequate clotting factors or cannot regulate the ability of the blood to clot properly.

Appetite stimulants (oxazepam, cyproheptadine) may be tried, but are seldom useful. They seem to work best in the recovery phase of the disease.

Ursodeoxycholic acid, a drug that improves bile flow within the liver, may be helpful in selected cases.

Section: Follow-Up

Optimal treatment for a cat with hepatic lipidosis requires a combination of home and professional veterinary care. Follow up can be critical, especially if your pet does not rapidly improve. With early detection and aggressive nutritional support, survival rates for hepatic lipidosis are 60 to 80 percent.

Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your pet.

Follow strict instructions concerning the care and management of any feeding tube that has been placed in your cat.

Follow strict feeding instructions in terms of the type of food, amount of food, and frequency of feeding, as dietary therapy is the most important aspect of therapy. As the cat improves, tube feeding should be decreased, and palatable food offered so as to encourage the cat to eat on his own. The tube is removed when the cat is voluntarily eating enough to meet his energy requirements.

Your cat should be re-examined every 3 to 7 days to have body weight, hydration status, and degree of jaundice evaluated.

A complete blood count, and a panel of blood tests evaluating the liver should be performed every one to two weeks during treatment.