Introduction
The liver is unique in that it has a large reserve capacity along with some regenerative power. Therefore, treating canine liver disease can be effective if the diagnosis is made early, depending upon the underlying cause of the problem. The goals of treatment are to eliminate any harmful agents or minimize their detrimental effects on the liver, promote healing and regeneration, prevent or control complications of liver dysfunction, treat the underlying cause when possible and keep the dog as comfortable and stable as possible until sufficient liver functioning may be re-established.
Treating Liver Disease in Dogs
Treatment protocols for dogs with liver disease will vary based upon the cause of the disorder. Acquired liver diseases in dogs are extremely diverse, especially chronic disorders which are collectively referred to as “chronic hepatitis.” Chronic hepatitis in dogs is really a range of disorders with similar historic features and clinical signs. It can be familial (especially in Bedlington Terriers, Doberman Pinschers, West Highland White Terriers, Skye Terriers and Dalmatians), but it also can be caused by infection, ingestion of certain drugs or toxins or by unknown factors. Liver disease in dogs can be caused by fibrosis, congenital vascular disorders, a wide variety of toxins, biliary tract disorders, abscesses and various types of neoplasia (cancer). Of the cancers, hepatocellular carcinoma is by far the most common type of primary liver tumor in dogs, although certainly other types occur. Many forms of cancer can metastasize to the liver as well. Liver disease can be acute in onset rather than chronic in many cases. While treatment options vary depending on cause, they will often include some or all of the following approaches and will often be long-term.
Dietary Modification
Dietary adjustments are normally recommended to ensure that a dog with liver disease gets the calories and nutrients necessary to support liver regeneration and manage the signs of hepatic encephalopathy. These diets can be commercial or homemade and tend to contain very digestible, high-quality but restricted levels of protein, to reduce metabolic demands on the liver. Protein restriction is also important to reduce the levels of circulating ammonia, which is caused by bacterial breakdown of protein in the gut. Non-meat sources of protein, such as dairy products (cottage cheese) and eggs, are preferred in diets for dogs with liver disease. Your veterinarian might prescribe regulated portions of carbohydrates, vitamins, proteins, minerals and fats. Dietary sodium should be restricted in cases of abdominal fluid retention. In addition to dietary changes, your veterinarian might suggest vitamins and other supplements that may improve liver functioning and promote regeneration, such as Vitamin E, Vitamin C, Vitamin K, Zinc, S-adenosylmethionine (“SAM-e”), milk thistle (silybin) and/or Ursodiol.
Prevention/treatment of Copper Excess
For familial liver disorders associated with excess copper accumulation, the amount of ingested copper must be minimized. Your veterinarian may recommend several commercially available diets, prescription diets and/or diets that can be made at home and that contain restricted copper levels. She may also recommend supplementation with zinc or copper chelating agents.
Medication
In many cases of liver dysfunction, drug therapy is appropriate. Glucocorticoids (“steroids”) have been suggested to prolong survival times in dogs with liver disease, due to their anti-inflammatory and immunosuppressive effects, although their use and appropriate dosage protocols are controversial. Azathioprine has been used in combination with steroids to manage certain adverse effects of those drugs; azathioprine can contribute to bone marrow damage.
Antibiotics are sometimes prescribed to combat bacterial infections, such as in cases of hepatic abscesses. Other drugs have been used to combat liver fibrosis, including colchicine. Studies of this anti-fibrotic agent in people show remarkable improvement in clinical signs and survival rates. Some dogs have been shown to benefit from its use as well, although reported side effects include diarrhea, vomiting and abdominal discomfort. Medications might be recommended to relieve vomiting, gastrointestinal bleeding and ulcers, if present. These can include ranitidine, famotidine or omeprazole, usually in combination with sucralfate.
Lactulose is commonly prescribed in cases involving hepatic encephalopathy to increase the dog’s gastrointestinal tolerance of proteins. Lactulose is broken down by bacteria in the colon and traps ammonia molecules there, making them non-absorbable and therefore excreted in the dog’s feces. Lactulose also changes bacterial metabolism so that less ammonia is generated in the first place. If the dog has seizures associated with its liver disease, barbiturates such as phenobarbital may be recommended, although generally barbiturates should be avoided in cases of liver disease. Other medications will no doubt be developed over time to help treat the causes and consequences of liver disease. Drugs that require metabolism by the liver to become effective (or to be eliminated by the body) should be avoided, and all drugs should be prescribed conservatively and in moderate doses in dogs with liver disorders.
Supportive Care
Sometimes, liver disorders are treated only with supportive care, although normally supportive care accompanies other treatment methods. Intravenous or subcutaneous fluids may be given to address dehydration and restore proper electrolyte balance. Antacids or other medications for taxing symptoms like vomiting and diarrhea can be prescribed. Of course, a safe, calm, temperature-regulated environment and a healthy diet are essential.
Blood Transfusion
Blood transfusion may be necessary in dogs with severe bleeding disorders associated with their liver disease. Only fresh whole blood or fresh packed red blood cells should be used, because stored blood products contain high ammonia concentrations, which is undesirable in cases of liver disease as it can contribute to the behavioral and neurological signs associated with hepatic encephalopathy.
Surgery
When the diagnosis involves an identifiable liver mass, the treatment of choice is surgical removal. Hemorrhage is the most common complication of these surgeries, and fresh blood products should be available in case transfusion is necessary during or following surgery. Dogs with liver disease are anesthetic risks, because most anesthetic agents are processed in the liver. Chemotherapy can be used for some forms of liver cancer as well. Unfortunately, treatment options are very limited for those cancers affecting more than one part of the liver.
Newer Treatment Options in Development
Efforts are being made to explore new treatment options for companion animals with liver disease - especially for those with cancer. These include intra-arterial chemotherapy, trans-arterial chemoembolization, percutaneous ethanol injections, microwave coagulation and various immunotherapeutic strategies. While these potential therapies are beyond the scope of this article, you might discuss them with your veterinarian if your pet is diagnosed with hepatic neoplasia.
The liver is a remarkably complex organ that can malfunction in multiple ways. Specific treatment protocols and an accurate prognosis will depend upon the type and cause of the liver dysfunction. Only a veterinarian can assess which treatment methods are best in any given case of canine liver disease.