Chronic Active Hepatitis (CAH) in Dogs
Dr. Bari Spielman
Goals in the treatment of CAH include eliminating any underlying cause; decreasing inflammation within the liver and providing an environment in which the liver can recover; controlling any complications; and attempting to stop progression of the disease. Patients with CAH may need to be hospitalized and treated aggressively. Depending on the stage of disease and clinical signs involved, outpatient therapy may or may not be sufficient. It is extremely important to have a diagnosis confirming CAH prior to treatment, as treating the symptoms is often ineffective. Eliminate or treat any underlying disorders if at all possible. Use antibiotics for bacterial infections. Stop the administration of all drugs that are cleared by the liver.
The animal is hospitalized and intravenous fluid and electrolyte therapy is instituted as needed for dehydration or to correct electrolyte disturbances from severe vomiting and diarrhea.
Intravenous nutrition may be started in malnourished dogs or dogs that cannot retain food due to vomiting.
Dietary recommendations for dogs with liver disease include reducing the amounts of protein in the diet and changing to a higher quality of protein. A major dilemma in formulating these diets is that the animal is often malnourished, and it is vitally important to maintain body weight and muscle mass while minimizing the signs of liver failure. There are commercial prescription diets available that are designed to provide reduced levels of high quality protein, including Hill's Prescription Diet L/D. Formulas are also available for making homemade diets.
Choleretic drugs that enhance bile flow, such as ursodeoxycholic acid (Actigal®), may be tried. In addition to protecting liver cells from the local effects of bile acids, it also has anti-inflammatory properties.
SAMe (Denosyl®) can be administered in an attempt to improve the metabolism of the liver. It is manufactured in the normal liver, but its production is often deficient in the diseased liver, so replacement therapy with SAMe may be beneficial.
Corticosteroids, such as prednisone, may be administered when active inflammation is demonstrated on the liver biopsy. The administration of prednisone may make some of the clinical signs associated with CAH worse (such as retention of fluid in the abdomen, ulceration of the stomach and intestinal tract, bacterial infections), and the drug is somewhat hard on the liver itself. The use of prednisone must be decided on a case-by-case basis.
When copper storage is involved in CAH, specific treatments that limit the accumulations of copper can be tried.
Antifibrotic drugs, or drugs that decrease scarring in the liver, may be tried, especially when scarring is a prominent finding on the liver biopsy. The most common drug used to decrease scarring is colchicine.
Fluid accumulation in the abdomen (ascites) may be treated with diuretics to facilitate removal of fluid. Such diuretics include spironolactone (Aldactone®) and furosemide (Salix®). Ascites due to low circulating blood protein levels may improve with the intravenous administration of plasma and other blood expansion products.
Although drugs that alter the immune system have been used in the past to treat CAH, currently their use is reserved for those cases that do not respond to other therapies. The most common immune-modulating drug used in dogs with CAH is azathioprine.
Gastrointestinal ulceration is a common complication of chronic liver disease. It may be prevented with drugs that decrease acid production by the stomach. Cimetidine (Tagamet®), famotidine (Pepcid®), ranitidine (Zantac®), and omeprazole (Prilosec®) can be used for this purpose.
Coagulopathies are clotting disorders associated with liver disease and are treated with injectable vitamin K.
Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your pet does not improve rapidly. Administer all prescribed medications and diets as directed. Alert your veterinarian if you are experiencing problems treating your pet.
Initially blood tests are taken every few weeks to monitor response to therapy and the status of the liver. As the animal stabilizes, the testing frequency may be decreased to every 4 to 6 months.. In patients with ascites, monitor body weight on a daily basis. As fluid is lost from the body, the dog's body weight will drop.
A second liver biopsy is often needed at some point to assess what is happening on a cellular level within the liver. This disease is very difficult to treat and is rarely cured. With consistent care and monitoring, the progression of the disease can sometimes be slowed, and the dog can be provided with a good quality of life. If the disease is ignored or if treatment and monitoring are inconsistent, then CAH often progresses to cirrhosis of the liver and end stage liver failure.