Canine copper-associated hepatitis: A retrospective study of 17 clinical cases

Copper hepatopathies in Australian dogs

INTRODUCTION

To evaluate hepatopathies in Australian dogs according to the World Small Animal Veterinary Association (WSAVA) guidelines. Specifically, to describe the prevalence and survival of dogs with copper-associated hepatopathy.

MATERIALS AND METHODS

Medical records from the Small Animal Specialist Hospital were reviewed to identify dogs with liver disease and liver biopsy between November 2008 and November 2021. Liver histopathology reports were reviewed with a board-certified veterinary pathologist and classified according to the WSAVA guidelines. Histopathology reports and clinical records were reviewed to ascertain the most important histological process for statistical analysis. Copper-associated hepatopathy was defined as (i) histological evidence of copper accumulation in centrilobular areas (Zone 3) associated with hepatocyte necrosis, inflammation with copper-laden macrophages and chronic hepatitis (ii) histochemical copper staining showing hepatocyte copper accumulation in the centrilobular areas and iii) hepatic copper measurement with concentrations greater than 600 μg/g dry weight of liver. Dogs with primary inflammatory parenchymal disease included dogs with copper-associated hepatopathy, idiopathic chronic hepatitis, non-specific reactive hepatitis, chronic bacterial hepatitis and immune-mediated chronic hepatitis. Descriptive statistics were performed for all dogs. Age, weight and clinicopathologic data were compared between dogs with copper-associated hepatopathy and dogs with other causes of chronic primary inflammatory parenchymal liver disease (Kruskal-Wallis test). Survival times were calculated and compared (Kaplan-Meier curves and log rank test) between dogs with copper-associated hepatopathy and dogs with other chronic primary inflammatory parenchymal liver diseases. Breed was evaluated to determine the breed most commonly affected with copper-associated hepatopathy and identify any breed in which this disease has not previously been described.

RESULTS

Sixty-seven (43 female, 24 male) dogs with a median age of 7.8 years (quartile [Q] Q1-Q3 4.5-9.6 years) were included. Thirteen dogs had copper-associated hepatopathy, eight dogs had idiopathic chronic hepatitis, eight dogs had non-specific reactive hepatitis, seven dogs had disorders associated with portal hypertension, five dogs had chronic bacterial hepatitis and four dogs had immune-mediated chronic hepatitis. Compared with dogs with other causes of chronic primary inflammatory parenchymal liver disease, dogs with copper-associated hepatopathy tended to be younger (6.73 vs. 8.01 years, P = 0.057) and heavier (19.8 vs. 9.6 kg, P = 0.052) than dogs with other causes of primary chronic inflammatory parenchymal diseases. There was no statistically significant difference when ALT (P = 0.30), ALP (P = 0.18) and total bilirubin (P = 0.13) were compared between the two groups. The median survival time for all dogs after liver biopsy was 2010 days (CI 1321 days - not reached). There was no significant difference in survival between dogs with copper-associated hepatopathy and dogs with other causes of chronic primary inflammatory parenchymal liver disease (P = 0.5).

CONCLUSIONS

Copper-associated hepatopathy was common among Australian dogs with chronic hepatopathies, occurring in younger and heavier dogs than other causes of primary inflammatory parenchymal liver disease. Clinical pathology is not useful for differentiating between copper-associated hepatopathy and other causes of chronic primary inflammatory parenchymal liver disease. When copper-associated hepatopathy is treated, the prognosis can be good. This is the first report of copper-associated hepatopathy in Australian Cavalier King Charles Spaniels.

Copper-associated chronic hepatitis in Cavalier King Charles spaniels

BACKGROUND

Copper-associated chronic hepatitis (CuCH) is poorly characterised in Cavalier King Charles spaniels (CKCS).

METHODS

Hepatic copper accumulation was qualitatively and quantitatively assessed, and blood samples were used for genetic testing to screen for known CuCH-associated genetic variants.

RESULTS

The study included 13 CKCS with CuCH and eight unaffected controls. Increased transaminase activities, elevated biliary enzyme concentrations and portal hypertension were documented in 100%, 73% and 38% of dogs with CuCH, respectively. Five dogs had three or more abnormalities in measures of liver function. All 11 dogs with CuCh that underwent genetic testing were homozygous negative for the COMMD1 deletion and ATP7A variant but homozygous positive (n = 7) or heterozygous (n = 4) for the ATP7B variant. Liver histology often demonstrated marked architectural distortion by severe, bridging fibrosis and regenerative nodules with lymphoplasmacytic inflammation. Centrilobular copper accumulation characterised early cases with minimal fibrosis. When fibrosis was significant, copper was often differentially concentrated within regenerative nodules. Chelation therapy resolved laboratory derangements and portal hypertension in five of seven dogs. Of the 7 non-surviving dogs with CuCH, 6 had not received chelation therapy.

LIMITATIONS

Limitations include a small cohort size and the lack of pedigree analyses to corroborate heritability.

CONCLUSIONS

CuCH should be considered in CKCS with suspected liver disease. Long-term prognosis seems favourable in dogs receiving chelation therapy, notwithstanding the presence of previously reported negative prognostic markers.

Nutritional management of a dog with hepatic enzymopathy suspected to be secondary to copper-associated hepatitis: a case report

A 4-year-old, female-spayed American Bulldog presented to the Ontario Veterinary College's Health Sciences Center's Clinical Nutrition Service for nutritional management of hepatic enzymopathy and suspected copper-associated hepatitis. Medical history revealed a 3-month history of gradually increasing serum ALT. Additional diagnostics included negative Leptospira titters, normal bile acids, and laparoscopic liver biopsy. Histopathology findings were consistent with diffuse moderate vacuole hepatocellular degeneration, mild positive copper staining, mild chronic lymphoplasmacytic hepatitis both portal and central, and mild biliary hyperplasia. Hepatic copper quantification results were above normal ranges (630 μg/g dry tissue), but below those seen in familial copper-associated hepatitis (>800-1,000 μg/g dry tissue). The patient was prescribed ursodeoxycholic acid, recommended to be fed a homemade diet (HMD), and referred for a nutrition consult. Two days before the nutrition consult, serum ALT fell within the normal range. The body condition score was 5/9, with a good muscle condition score and the dog's appetite and body weight remained stable. Energy intake was appropriate for maintenance. Key nutrient levels of all diets reported were compared to industry standards (AAFCO, NRC, and FEDIAF). Diet history included a commercially available raw meat-based diet (RMBD), of unknown copper content; a high energy commercial dry food (HEC), with copper content higher than the maximum recommended by FEDIAF and immediately prior to nutrition consult the patient had been eating an unbalanced homemade diet (HMD1) for 4 weeks. HMD1 was low in copper and deficient in the hepatoprotectant nutrients vitamin E and zinc. As per the owner's preference and to accommodate the patient's unique nutritional needs, a homemade diet addressing key nutrients for liver disease was formulated (HMD2), with copper content just above the recommended minimum. The new diet was found palatable and the patient's body weight, body, and muscle condition scores remained unchanged. Two months after starting HMD2, all bloodwork values remained within the normal range, including ALT. The reduction of dietary copper content likely reduced serum ALT. However, unbalanced diets cause a risk of nutrient deficiencies and excess. This dog was maintained with no known adverse effects on a complete and balanced HMD diet with a moderately low copper content, moderate protein, and inclusion of hepatoprotective nutrients.

Low alanine aminotransferase activity gene variant in a Siberian Husky with copper-associated hepatopathy

BACKGROUND

Alanine aminotransferase (ALT) is commonly used as a marker of hepatocellular injury. Increased serum ALT activity due to hepatocyte injury occurs in copper-associated hepatopathy (CuCH) and other necroinflammatory liver conditions. Blood ALT concentrations are frequently used to monitor therapy in cases of CuCH. Low serum ALT activities have been associated with an allele at a CFA13 locus.

CASE PRESENTATION

A 9-year-old female spayed Siberian Husky was diagnosed with CuCH (hepatic copper dry weight 2680 µg/g [normal, 120-400 µg/g; toxic, > 1500 µg/g]) and a normal ALT (78 U/L; reference range, 10-125 U/L). Mild hepatocellular necrosis was evident histologically. Genetic testing (Embark) revealed that the dog was heterozygous for the low ALT activity gene allele.

CONCLUSIONS

This case report illustrates the clinical implications for diagnosing and managing necroinflammatory liver disease such as CuCH in dogs with a low ALT activity genotype.

D-penicillamine-associated neutropenia in a Doberman pinscher

Copper-associated hepatitis in dogs results from elevated copper levels secondary to increased intake or decreased clearance. Treatment is through establishing a negative copper balance and can include chelation therapy. Traditionally, chelation therapy in dogs is uses D-penicillamine, which has been shown to have severe side effects in humans. Side effects have not been well-documented in dogs but can include nephrotoxicity and dermatologic reactions. This article is the first to report neutropenia in a dog secondary to chelation therapy using D-penicillamine. In this case, a complete blood (cell) count (CBC) collected before initiation of chelation therapy was normal and neutropenia was documented 4 mo after starting therapy. A cytologic examination of bone marrow confirmed a myeloid hypoplasia. Following discontinuation of D-penicillamine, the neutropenia resolved. Based on this case report, periodic CBC rechecks following the initiation of D-penicillamine chelation therapy are recommended to guide treatment decisions. Key clinical message: Dogs with confirmed copper-associated hepatitis should be treated cautiously with D-penicillamine for chelation therapy. D-penicillamine may adversely affect bone marrow, causing a leukopenia characterized by neutropenia. It is recommended that clinicians periodically monitor neutrophil counts while treating dogs with D-penicillamine.