Toxic encephalopathy associated with high-dose metronidazole therapy in a dog: a case report

This case report describes an episode of acute ataxia, tremor, vertical nystagmus and progressive weakness in a mixed breed dog treated with high doses of metronidazole. Complete blood cell count, serum biochemistry, coagulation profile, blood pressure measurement, urinalysis, computed tomography of the brain and cerebrospinal fluid examination were unremarkable. Metronidazole had been administered at a dose of 65 mg/ kg/day and neurotoxicity was, therefore, suspected. Drug concentrations in the patient’s serum and cerebrospinal fluid were measured using high-performance liquid chromatography and compared to control dogs. Metronidazole administration was immediately discontinued; supportive care consisted of fluid therapy and diazepam treatment. The neurological status of the patient improved rapidly within 72 h. The aim of this case report is to describe the clinical presentation of metronidazole intoxication in a mixed breed dog and to interpret the chromatographic analysis which can be a beneficial diagnostic and screening tool in dogs intoxicated with metronidazole.