Background: Little is known about etiology, disease progression, treatment outcome, survival time, and factors affecting prognosis in dogs with primary hepatitis (PH).Objectives: To review retrospectively different forms of hepatitis in a referral population, by the World Small Animal Veterinary Association Standardization criteria.Animals: One-hundred and one dogs examined for histologically confirmed PH between 2002 and 2006. Dogs with nonspecific reactive hepatitis were excluded.Methods: Retrospective study. Medical records were reviewed for prevalence, signalment, clinical and clinicopathologic manifestation, outcome, survival time, and prognostic factors for shortened survival.Results: PH occurred in 0.5% of dogs in this referral population. Acute (AH) and chronic hepatitis (CH) were diagnosed in 21 and 67 dogs, respectively. Progression from AH to CH occurred in 5/12 of the repeatedly sampled dogs. CH was idiopathic in 43 (64%) dogs, and was associated with copper accumulation in 24 (36%) dogs. Median survival time was longer in dogs with AH than in dogs with CH (either idiopathic or copper associated), and dogs with lobular dissecting hepatitis had the shortest survival time. Prognostic factors predicting shortened survival were associated with decompensated liver function and cirrhosis at initial examination.Conclusions and Clinical Importance: The majority of PH in dogs is CH. Previous studies appear to have underestimated the etiologic role of copper in both AH and CH. Prognosis is reduced in dogs with hepatic cirrhosis or cirrhosis-related clinical findings. Further research into etiology and treatment effectiveness in all PH forms is needed.

Background: Only one study reports prednisone to prolong survival in dogs with chronic hepatitis irrespective of the causative agent. The aim of this retrospective study was to investigate the effects of prednisolone treatment on survival, clinicopathological variables, and histological grade and stage of idiopathic chronic hepatitis in 36 dogs. Animals and methods: Medical records were reviewed of 36 prednisolone-treated dogs (median age: 8.6 years; range: 2.0-14.6 years) with chronic hepatitis not associated with primary copper accumulation. Clinicopathological results were analyzed pair-wise for 20 dogs, before and after oral prednisolone administration (1 mg/kg BW/day). Dogs were treated for at least 6 weeks, and for an additional 6 weeks if hepatitis was still present at rebiopsy. Follow-up data pertaining to clinical outcome and survival time (Kaplan-Meier estimate procedure) were analyzed. Results: At the follow-up, 11 dogs were in complete remission, 8 dogs had recurrent clinical signs, and 17 dogs had residual disease. Despite treatment, 20 dogs died of hepatitis-related causes. Dogs without cirrhosis survived significantly longer than dogs with cirrhosis. Prednisolone treatment normalized coagulopathies associated with chronic idiopathic hepatitis within one week in all 10 dogs that had coagulopathies at initial diagnosis. Conclusions: Our findings suggest that prednisolone has, in part, beneficial effects on hepatic inflammation and that it may, at least in some cases, limit the progression of fibrosis, which emphasizes the importance of early diagnosis and treatment. We did not see any benefit of prednisolone treatment for dogs with cirrhosis. We could document a highly favorable effect of prednisolone treatment on the coagulopathy associated with canine chronic idiopathic hepatitis.