Mycophenolate mofetil as a treatment for presumed idiopathic chronic hepatitis in dogs: Six cases (2010-2022).

OBJECTIVES: The objectives of this study were to describe the clinical findings, treatment and outcomes of six dogs with presumed idiopathic chronic hepatitis treated with mycophenolate mofetil (MMF). MATERIALS AND METHODS: Medical records were retrospectively searched to identify dogs in which idiopathic chronic hepatitis was diagnosed on histopathology between January 2010 and June 2022 that were treated with MMF for at least two weeks with >2 follow-up examinations. Data recorded from each dog included signalment, clinical signs, diagnostic test results and treatment. RESULTS: Six dogs were treated with MMF at a median initial dosage of 9.6 mg/kg PO q 12 h. Reported adverse effects from MMF included decreased appetite, vomiting and diarrhoea. In all six dogs, MMF was used successfully long term for the treatment of idiopathic chronic hepatitis as determined by 46% or greater improvement of alanine aminotransferase (ALT) between 4 and 18 weeks of starting MMF. Three dogs were also temporarily treated for 4-6 months on a tapering dose of prednisone. In two dogs, ALT remained within the reference interval, and in one dog, it was very mildly elevated when on MMF alone. In all six dogs, owners reported that the medication was well tolerated. CLINICAL SIGNIFICANCE: To the authors' knowledge, this is the first report describing the use of MMF with and without a tapering dose of prednisone for the treatment of idiopathic chronic hepatitis in six dogs. Based on the outcomes of the dogs in this report, MMF can be effective for the long-term treatment of idiopathic chronic hepatitis as measured by reduction in ALT and improvement of clinical signs.

Post-chemotherapy perforation in cats with discrete intermediate- or large-cell gastrointestinal lymphoma.

Objectives Gastrointestinal (GI) perforation is a well described complication of GI lymphoma in people, commonly occurring within days of initiation of chemotherapy. There are no studies documenting the prevalence of GI perforation in cats with intermediate- or large-cell GI lymphoma or whether it is associated with induction of chemotherapy. The objectives of this study were to document the prevalence and timing of post-chemotherapy perforation in cats with discrete GI masses caused by intermediate- or large-cell lymphoma. Methods Cats with a diagnosis of intermediate- or large-cell lymphoma based on cytologic or histopathologic examination of a mass lesion of the GI tract and treated with chemotherapy were identified by searching the patient record database of three large specialty referral hospitals. Cats undergoing surgical resection of a GI mass prior to chemotherapy were excluded from the study. A clinical diagnosis of GI perforation was made using ultrasound findings and analysis of abdominal fluid. Results Twenty-three cats with intermediate- (n = 3) or large-cell (n = 20) lymphoma were included in the study. GI perforation was confirmed in 4/23 cats (17%), and occurred at 23, 56, 59 and 87 days after induction. There was no association between tumor size, the presence of hypoproteinemia or suppurative inflammation within the mass at the time of diagnosis and subsequent perforation. Post-hoc analysis revealed that the magnitude of weight loss within 15-28 days of diagnosis was greater in cats with perforation. Conclusions and relevance In this pilot study, we found that post-chemotherapy GI perforation in cats with intermediate- or large-cell GI lymphoma occurs. Acute perforation after induction of chemotherapy was not documented. Larger prospective studies are needed to determine risk factors associated with perforation and whether surgical excision would reduce the risk of subsequent GI perforation in these patients.