Article Compiled by Myra Ehrman, RN, BA, BS, MScN, on behalf of the Health Education Committee, CKCSCC originally Published in The Cavalier King Charles Spaniel Club of Canada Newsletter, "Quotes", in July, 1995
At the end of 1994, one of our club members wrote requesting further information about copper storage disease, as she had lost a dear little friend to this disease. The Health Education Committee set about doing some research. The outcome of this research shows that while this particular disease has not yet been identified as specifically affecting the Cavalier KCS breed in great numbers, the list of affected breeds is growing. The breeds in which this disease has already been identified as an inherited problem include the Bedlington Terrier, the Doberman Pinscher, the West Highland White Terrier, and the Skye Terrier. Two articles in the VETERINARY CLINICS OF NORTH AMERICA-SMALL ANIMAL PRACTICE, March, 1995, both identified the American and English Cocker Spaniels as being amongst the 23 breeds of dogs now found to have a high representation of accumulation of copper (a metallic element) in the liver. Male Cockers were affected more often than females, with the average age of diagnosis being 5 years. The reason for this article is to provide further background about the symptoms, diagnosis, and treatment of copper storage disease so we can all be more knowledgeable about the disease, and watch for further occurrences.
SYMPTOMS
The liver is an important part of regulating body copper concentration
(copper is the third most abundant trace element in the body after iron and zinc). By the
time the owner or vet can see there is something wrong with the dog, the disease may
already be well established, with resulting inflammation and degeneration of liver cells.
The inflammation and degeneration occur because any excess copper is excreted in the bile,
and once the copper is no longer excreted normally, it begins to accumulate, and becomes
toxic to the liver.
There is a similar disease which occurs in people known as Wilson's
disease. In people, clinical signs (evidence found on exam) are associated with the liver
or central nervous system. In dogs, these clinical signs reflect the involvement of the
liver. Such symptoms may include: loss of appetite, vomiting, weakness, weight loss,
lethargy or lack of energy, depression, dehydration, jaundice (yellowing of eyeballs),
enlarged abdomen due to abnormal accumulation of fluid, increased need to urinate and to
drink, emaciation and debility, evidence of brain disorder, and hemolytic anemia.
DIAGNOSIS
Disorder of copper metabolism should be considered as a possible cause
of all chronic liver disease. Blood tests alone are not sufficient to make the diagnosis;
specific diagnosis requires liver biopsy.
TREATMENT
Treatment is aimed at accomplishing: 1) decreasing any further
absorption of copper from the gastrointestinal tract, and
2) enhancing excretion of copper. Copper content of the diet can be
decreased, and there are drugs available which prevent the absorption of copper already
taken into the body. Copper excretion from the liver can also be enhanced by using copper
chelating agents. (A chelate combines with a metal in weakly dissociated complexes in
which metal is part of a ring, hence helping to remove it from the system, primarily
through the kidneys).
With respect to diet, most commercial dog foods meet or exceed
requirements for copper, so special diets are required. Any homemade diet which does NOT
contain organ meats, shellfish, or cereal is suitable. Vitamin supplements which do not
contain any copper are recommended. A diet low in copper will be most effective for the
management of young dogs which are known to have inherited liver (hepatic) copper
metabolism defect. Low copper-containing foods include fresh fruits, vegetables, most
beef, pork or poultry (NOT organ meats), eggs, fish (NOT shellfish), dairy products,
processed meats such as hot dogs, white rice, and processed white flour.
Copper chelating agents would be prescribed by vets and would be taken
orally by the dog. Therapy with these drugs are long term, and take months to years to
cause a substantial reduction in copper in the liver. At least one of these drugs can have
toxic side effects of its own, such as vomiting and loss of appetite.
Some animals with chronic hepatitis (inflammation of the liver) may
benefit from anti-inflammatory therapy. Vitamin E therapy, in doses of 400 to 500 mg/day
orally may also help protect against liver damage from copper. Oral zinc supplementation
also seems to help decrease new absorption of copper, although it is seen to have little
effect on decreasing the copper if the concentration had been increased already. In people
who have been affected, supplemental zinc has been used to prevent new accumulations of
copper once levels were decreased with chelating agents. Zinc works best if given at least
1 hour before meals, but if nausea or vomiting occur when giving it on an empty stomach, a
small piece of meat can be given with it. Treatment of copper storage disease is probably
life-long, with periodic liver biopsies and copper concentration analyses (blood work).
If you have or know of Cavaliers diagnosed with liver problems,
especially copper storage disease, you might want to keep the Health Education Committee
up to date, so we can start monitoring frequency of occurrence.
The Health Education Committee gratefully acknowledges the assistance
in locating background articles provided by Dr. Stan Rubin, Department of Veterinary
Internal Medicine, Western College of Veterinary Medicine, University of Saskatchewan.
Disclaimer: Your veterinarian is the most qualified person to answer all of the
questions you have about your pet's health. Nothing in this article should be construed as
medical advice regarding any individual animal’s condition.
© Copyright April 11, 1999.
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