An inflammatory condition of the liver with numerous potential causes.

Chronic active hepatitis is a persistent inflammatory syndrome that over time destroys the functional cells of the liver (hepatocytes). This condition, which affects dogs, may progress to cirrhosis, liver failure and death. It tends to occur more frequently in Bedlington terriers, West Highland terriers, Doberman pinchers, American and English cocker spaniels, Labrador retrievers, and Skye terriers. Although there are a number of potential causes, the pathologic mechanisms underlying chronic active hepatitis are poorly understood. Proposed mechanisms are modeled after similar (but not the same) ones occurring in human hepatitis. Chronic active hepatitis may be a consequence of the immune system targeting the liver as foreign and attacking it, or some other process where the immune system is not properly regulated. Various toxic substances, including certain anti-convulsant and heartworm medications, could cause it as well. Copper accumulation in the liver is strongly associated with chronic active hepatitis in some dogs. Bacterial, parasitic or fungal infections may cause chronic active hepatitis in dogs, but uncommonly so. The tendency for chronic active hepatitis to occur significantly more often in certain breeds over others suggests breed-associated causes. Although a variety of underlying mechanisms may cause the condition, chronic inflammation in the liver results. Liver cells die and are gradually replaced by patches of fibrotic tissue that prevents liver tissue regeneration. In some cases these fibrotic patches merge and cirrhosis (severe scarring) results. Fibrosis of the liver may be reversed with treatment. Cirrhosis is not reversible. Liver dysfunction occurs and causes signs of liver disease late in the process. Affected dogs may experience loss of appetite, depression, and weakness. They may have jaundice, lose weight, and vomit frequently. Polydipsia (excessive drinking) and polyuria (excessive urination) may occur as well. Diagnosis is based on clinical history and signs, blood tests, radiographs (x-rays), and a liver biopsy. Serum ALT and ALP (liver enzymes) will be significantly elevated, as much as five to ten times normal. The blood will contain abnormally low amounts of albumen. If copper accumulation is the cause, copper levels in the blood will be elevated above normal. Radiographs will reveal that the liver is reduced in size. There are few specific treatments. Therapeutic goals include elimination of suspected or known causes; suppression of inflammation and other nonspecific mechanisms that contribute to disease progression; provision of an environment to permit healing; and control of secondary complications such as bleeding disorders, gastric ulceration, ascites (abnormal abdominal fluid accumulation), infection, and electrolyte imbalances. Anti-inflammatory treatments and choleretics (agents that promote bile flow) are used commonly to treat chronic active hepatitis. Anti-cancer drugs are also used in some cases. Special sodium- and protein-restricted diets are commonly advised. Cholchicine (a drug sometimes used to treat the acute onset of gout in people) may be attempted in some patients to disrupt the formation of fibrotic tissue. Treatment tends toward management of the disease process rather than cure. The prognosis for recovery is dependent upon many factors. These include the severity of the disease, its response to treatment, complications and the associated degree of scarring or fibrosis. Some cases of chronic hepatic disease can be effectively treated until there is a remission of signs. Please discuss this with your veterinarian. He or she may direct you to a veterinary internist for consultation.

11/19/03