Toxic encephalopathy associated with low dose metronidazole therapy in a cat suffering from gastrointestinal lymphoma: A case report

This case report describes an episode of acute encephalopathy in a cat treated with metronidazole due to chronic gastrointestinal disease (giardiasis). Metronidazole had been administered at a dose of 28 mg/ kg/day for 7 days. Cat showed signs of head pressing, reduced consciousness, ataxia, seizures, lack of menace response and progressive weakness. Complete blood cell count revealed haemolytic anaemia, serum biochemistry, coagulation profile, blood pressure measurement, urinalysis, were unremarkable. Metronidazole administration was immediately discontinued; supportive care consisted of fluid therapy, blood transfusion was also performed. The neurological status of the patient improved rapidly within 72 h. Anaemia improved in next 7 days, however transfusion and steroid treatment was necessary. Two weeks post intoxication abdominal ultrasound revealed abnormal hepatic pattern, enlarged mesenteric lymph nodes and lack of normal intestinal layering. A biopsy had been taken during explorative laparotomy and histopathologic examination revealed gastrointestinal and hepatic lymphoma. The aim of this case report is to present that cats suffering from multiple conditions may show metronidazole intoxication even when recommended dosage and treatment length is used. We cannot exclude that metronidazole was responsible for autoimmune haemolytic anaemia.