Chronic canine hepatitis is a poorly understood, progressive liver disease that is characterized by active inflammation and fibrosis, or irreversible scarring, of liver tissue. Ultimately, it leads to necrosis – or death – of liver cells, which are known as hepatocytes. The damage to the liver is diffuse, meaning that the whole organ is affected rather than just a particular part of it. Chronic hepatitis typically progresses in a distinct series of stages. Initially, the disease is subclinical, which means that the affected dog shows no outward signs of illness even though the disease is present. During this phase, the liver swells and becomes abnormally rubbery and firm. Liver cells are dying and being replaced by scar tissue. The dog usually will have abnormally elevated levels of liver enzymes on routine blood work but will show no other outward signs of discomfort or disease. The next stage is clinical hepatitis. This means that the affected animal will show one or more observable signs associated with the disease, which are listed below. Finally, by the third (and final) phase of chronic canine hepatitis, the liver has become abnormally firm and rubbery and has been partitioned by constricting scar tissue into a mass of irregular nodules. At this point, the dog has irreversible liver cirrhosis and hepatic (liver) failure.
“Idiopathic” means of unknown origin, and this disease is often referred to as idiopathic canine hepatitis, because the cause or causes of chronic canine hepatitis are not known. Many experts think that it may have an autoimmune component, which means that a weakened or overactive immune system may play a leading role. The hypothesis is that for some reason, a dog’s immune system is stimulated to make antibodies against its own liver cells, which in
Chronic canine hepatitis is always a progressive disease. However, the liver has an enormous reserve capacity; in fact, up to 70% or 80% of liver tissue must be destroyed before the liver will fail. Most dogs with hepatitis will not feel sick (or at least will not show outward signs of feeling sick, which is really all that we can assess) until a very substantial portion of their liver is destroyed. Once that happens, the
The attending veterinarian will take a complete history from the dog’s owner and will perform a thorough physical examination. The initial data base usually will also include taking a blood sample for submission to a laboratory for a complete blood count and a serum biochemistry profile. The very first clue that a dog may have hepatitis is elevated liver enzymes in the blood. The serum chemistry panel is critical to identifying abnormal levels of circulating
The goals of treating a dog with chronic hepatitis are to stop the progression of the disease, provide excellent nutrition and other support for the liver, remove the inciting cause if it can be identified and keep the dog as comfortable as possible so as to maintain a comfortable, pain-free quality of life. If the dog has acute complications associated with its chronic disease, it may need to be hospitalized. That will enable the veterinary