Many things can cause inflammation and scarring in the liver, including infections, toxins, autoimmune disease, storage disorders (e.g., copper), and genetic factors. Doberman pinschers, Cocker spaniels, Bedlington terriers, West highland white terriers, and Skye terriers are predisposed. When an inciting cause cannot be found, the disease is said to be “idiopathic,” meaning we don’t know why it developed in that individual. Unfortunately, most cases of CAH in dogs are idiopathic.
The liver plays many roles within the body, including protein, carbohydrate, and lipid metabolism, the break-down of toxins, manufacturing bile (an important digestive fluid), making blood coagulation factors, vitamin storage, blood filtration, and the metabolism of drugs. A healthy liver has more functional capacity than is actually needed, so dogs in the early stages of CAH appear perfectly normal. But as the damage continues, the liver’s "reserves" eventually run out and affected dogs develop some combination of increased thirst and urination, loss of appetite, vomiting, diarrhea, jaundice, fluid accumulation in the abdomen, altered behavior and mentation (a condition that is called hepatic encephalopathy), jaundice, and abnormal bleeding.
Treating chronic active hepatitis can get complicated. Any possible underlying factors need to be addressed (e.g., antibiotics for bacterial infections or medications that bind to copper and remove it from the body), and the use of drugs that can be toxic to the liver must be avoided. Immune suppressants such as prednisone, azathioprine, and cyclosporine should be considered on a case by case basis. Ursodeoxycholic acid and s-adenosyl-L-methionine (SAMe) are frequently prescribed to support liver function and health. Drugs to control the complications of CAH, such as abdominal fluid accumulations, hepatic encephalopathy, gastrointestinal ulcers, and blood clotting disorders may also be necessary.
Diet plays an important role in treating dogs with CAH. Because poor appetite and weight loss can be a big problem for these patients, it is important to find a nutritious food made from high-quality ingredients that a dog will eat well. When a patient begins exhibiting signs of hepatic encephalopathy, a reduced protein diet made from high-quality protein sources can be helpful.
The liver is a resilient organ. When caught early, some dogs with CAH can be successfully managed and enjoy a good quality of life for many years. Advanced cases tend to do more poorly, however. In either case, frequent rechecks are necessary to make sure everything possible is being done as the disease progresses and the patient’s clinical picture changes.
Dr. Jennifer Coates