Copper Hepatopathy

Summary

When the liver becomes diseased, we'll often refer to the process as a "hepatopathy." With copper hepatopathy in dogs, the liver may:

1. Harbor an abnormal version of the proteins used to bind copper or...

2. Suffer from abnormal bile metabolism.

To understand how these situations cause disease you should know the basics: Copper is taken in through a pet's diet, absorbed by the intestines, and bound in the liver by proteins that allow for its proper excretion through the bile. If either the proteins or the bile are abnormal, the liver ends up accumulating the copper.

Because copper is not meant to remain in the liver, its continued presence results in chronic hepatitis (inflammation of the liver). This leads to cirrhosis (a sort of scarring of the liver) and eventually, to liver failure. Rarely, necrosis of the liver (cell death within the organ) can take place. This leads to copper toxicity which causes the widespread breakdown of red blood cells.

A deficiency in zinc may also cause the disease, though this is considered rare.

Symptoms and Identification

Dogs can be affected in one of three ways:

1. Young dogs with acute onset of severe anorexia, depression and vomiting. Sadly, most of these patients die relatively quickly.

2. Middle aged to geriatric dogs with a chronic history of on and off symptoms of lethargy and inappetance. Some may drink and urinate more. Others may suffer vomiting and diarrhea. In the end stages of the disease, signs related to liver failure will typically result. These include abdominal distension (ascites), jaundice, clotting problems, and neurologic symptoms (called "hepatic encephalopathy).

3. Some dogs will show no symptoms at all. These are characterized as "subclinical" cases.

Diagnosing the disease is multifaceted; Lab work will include CBC, chemistry, bile acid testing, clotting times and (most importantly) liver biopsy to demonstrate high levels of copper. X-rays may either show a large liver (typically with acute disease), a small liver (usually seen in the chronic form's later stages) or, more commonly, nothing at all. Ultrasound testing is usually similarly unremarkable. To screen for copper hepatopathy, a stool test demonstrating the high presence of copper and/or a fine needle aspirate of the liver (less invasive than a biopsy) can be very helpful.

Affected Breeds

The following breeds are predisposed:

• Doberman Pinscher

• Bedlington Terrier

• West Highland White Terrier

• Skye Terrier

In the Doberman, females are overrepresented. In Bedlington terriers, the mode of inheritance is autosomal recessive. For all others the mode is as yet undetermined.

Treatment

For chronic and subclinical forms, treatment revolves primarily around copper chelation, a drug therapy used to bind the copper before it makes it to the liver. This is a lifelong approach for all. For acute sufferers, supportive care with fluids, antibiotics, anti-nausea drugs and other medications is required. For liver failure patients, the goal of treatment involves ridding the body of toxins the liver leaves behind in its inability to clear them. It also requires antibiotics to aid in the infections the liver can no longer keep at bay.

Lower protein diets are imperative for liver failure patients. Lower copper diets are indicated for all.

Veterinary Cost

The cost of diagnosis can be quite high, unless it is performed as a screening test (for potentially subclinical breeding dogs), in which case the liver can be sampled at the time of a spay or neuter. Basic liver biopsy for otherwise healthy dogs is a relatively simple procedure. It can even be performed laparoscopically. Expect to pay anywhere from $200 (as an add-on to a spay, for example) to $1,000 or more for very sick dogs.

For very ill dogs the costs can be quite high, depending on the degree to which they are affected. The intensive care required for some can run into many thousands of dollars.

For the chronically or subclinically affected, chelation drugs can get expensive.

Prevention

Luckily, strides have been made in identifying these patients early on. Biopsies taken at six months and again at 15 months (though usually undertaken only for high risk breeds entering a breeding program) can almost always rule out the disease before it causes problems--and before the genetic trait is passed along to any offspring.

It's been postulated that dogs eating a diet high in copper (many commercial dog foods allow for much of this mineral in their formulation) are more at risk. Feeding diets lower in copper is perhaps advisable for dogs whose breeds or lines render them at high risk, but it will not usually be sufficient to curtail the disease's ultimate progression.

References

Johnson SE. Diseases of the liver. In: Ettinger SJ, Feldman EC, eds. Textbook of veterinary internal medicine. Philadelphia: WB Saunders, 1994.

Twedt DC, Whitney EL. Management of hepatic copper toxicosis in dogs. In: Kirk RW, ed. Current veterinary therapy X: small animal practice. Philadelphia: WB Saunders, 1989.