Chronic hepatitis (CH) is a common hepatic disorder in dogs. Diagnostic criteria of canine CH include persistent ALT elevations >2 times normal and histopathologic features based on WSAVA guidelines, characterized by moderate to severe chronic inflammation, hepatocellular apoptosis or necrosis, and fibrosis. Most cases are classified as idiopathic and, therefore, optimal management for CH has not been established. Corticosteroids are reported to prolong survival in some dogs, suggesting an immune-mediated mechanism to the disease. However, corticosteroids cause significant side effects and induce a steroid hepatopathy that confounds interpretation of liver enzymes during therapy. To date, there are no studies investigating the use of alternative immunosuppressive therapy, such as cyclosporine (Cys), in the management of canine idiopathic CH.

The primary aim of this retrospective study was to evaluate the safety and efficacy of Cys in the treatment of idiopathic CH. A secondary aim was to identify any factors influencing Cys treatment response or time to remission. Remission was defined as normalization of serum ALT. Our hypotheses were that: 1) Cys therapy would achieve remission and 2) lower pretreatment clinical scores and higher serum ALT would predict prolonged times to remission.

Forty-six dogs diagnosed with idiopathic CH and treated with Cys met the inclusion criteria. Cases were excluded if there was a lack of biochemical data, concurrent immunosuppressive therapy, failure to complete at least 2 weeks of Cys therapy, or evidence of biochemical improvement with penicillamine or antibiotic administration. Twenty-five different breeds were represented. Ages ranged from 0.7–14 years with a median of 8 years. Fifty-two percent were female spayed and 43% were male castrated. Treatment side effects included gastrointestinal signs ranging from mild inappetence to vomiting and diarrhea in 39% and gingival hyperplasia in 26%. Thirty-five dogs (76%) achieved remission based on ALT normalization. The median time to remission was 3 months. Three dogs (6.5%) reached partial remission (ALT values declined but remained between 1.1 and 2x the upper limit of normal). Eight cases (17%) did not achieve remission. Initial serum ALT activity, hepatic copper concentration (>1000 µg/g dry weight), and clinical score did not influence remission.

Cys proved to be effective in achieving remission based on normalization of serum ALT in canine idiopathic CH. Limitations include the retrospective nature of the study, concurrent therapies given, variability of long-term followup, and the lack of post-treatment biopsies.

Disclosures

No disclosures to report