My cat was recently diagnosed with a chronic condition the veterinarian called "inflammation of the liver and bile ducts." Can you tell me about this condition? She was vomiting liquids of various colors and lost 30 percent of her body weight. She underwent two weeks of antibiotic treatment and when I brought her home she seemed better. Her appetite was very good but she seemed a bit listless, and she threw up most of the moist food I gave her. Her veterinarian said the next step is to put her on prednisone, and if this medication works the cat can live a full life. If it doesn't work, what else can be tried? I should note that she is very difficult to medicate orally.

Chronic Active Hepatitis, Choleangiohepatitis

Cholangiohepatitis, or inflammation of the liver and bile ducts, is a common problem in cats. The inflammation arises from either bacterial infection or immune-mediated processes, especially autoimmune ones, where the cat's immune system reacts against the cat's own tissues. Bacterial infections are often acute problems, and with treatment, may resolve within a few weeks. Immune-mediated cholangiohepatitis is likely to be chronic or subchronic and may last for weeks or months. The prognosis for recovery depends on the underlying cause.

Acute infections of the liver and biliary tree are often associated with ascending bacterial infection from the gastrointestinal tract. Cats with inflammatory bowel disease are predisposed to develop infectious cholangiohepatitis. Such infection may also be associated with pancreatic disease or any process that causes bile to be retained or to thicken.

Clinical signs of acute infection are nonspecific and include fever, vomiting, diarrhea, depression and weight loss. Blood tests of liver function will reveal abnormal values. Alkaline phosphatase and other liver enzymes are consistently elevated, but the magnitude of abnormality varies. The blood will also contain abnormal levels of bile acids and bilirubin. Increased clotting time is often seen. Jaundice may or may not be present.

Definitive diagnosis of the specific underlying cause requires liver biopsy and culture of the bile or tissue for specific bacteria. However, many patients are treated presumptively with broad-spectrum antibiotics. Biopsy results will also enable more reliable prognostication. Hepatic lipidosis (fatty liver), liver cancer, and other inflammatory diseases of the liver must be ruled out.

Antibiotic choices can be challenging. The ideal antibiotic would be secreted in bile and effective against many different types of bacteria. Often multiple agents are combined to achieve this. Some of these drugs are only available in injectable form, but most can be recompounded into liquid form or capsules for ease of administration. Veterinarians frequently advise two to three months of antibiotic therapy. Some clients learn to give injections if their pets must be treated chronically and are difficult to medicate orally.

Ursodeoxycholic acid is another medication that may be added to the antibiotics. It appears to reduce bile thickness and improve bile flow. It also reduces inflammation specifically within the liver. Additionally, ursodeoxycholic acid reduces the formation of proteins that trigger the autoimmune response against liver and bile duct cells. Side effects are limited with this medication, but it must be recompounded to an appropriate dose for cats.

If the liver inflammation becomes chronic, then other medications, such as corticosteroids, are frequently needed to suppress the inflammatory process. Antibiotics and ursodeoxycholic acid are also indicated. The underlying problem in chronic cases may be an excessive immunologic response to the bacteria or to some other unknown immunostimulus, as well as an autoimmune phenomenon. Samples of liver tissue are studied to discriminate between acute and chronic inflammation and to identify the specific cells infiltrating the liver.

Treatment and prognosis will vary according to the underlying disease. Cat patients with significant inflammatory liver disease have a guarded (uncertain) prognosis. Cats with acute or chronic cholangiohepatitis that survive the first three months after diagnosis are likely to be long-term survivors. If the inflammation involves lymphocytes, a type of white blood cell, and centers in liver tissue associated with the portal circulation, then the prognosis is less predictable.

If your cat does not do well, you may wish to speak with your veterinarian about referral to a veterinary internist for assessment. Abdominal ultrasound and liver biopsy may be advised; endoscopy may also be appropriate. Hepatic lipidosis or cancer of the liver cannot be ruled out without some tissue sampling.

07/23/02