Wernicke's Encephalopathy and Peripheral Polyneuropathy Developed during Long Term Metronidazole Therapy in a Patient with a Brain Abscess: A Case Report

ABSTRACT

Metronidazole can induce serious neurologic problems including peripheral neuropathy, seizures, and encephalopathy. We examined a patient with acute Wernicke's encephalopathy and peripheral polyneuropathy that had developed after prolonged metronidazole therapy without a history of chronic alcoholism or poor nutritional intake. The 68-year-old man had been hospitalized for a brain abscess and was treated for 10 weeks with metronidazole (2 grams per day). This patient, who showed symptoms of numbness and tingling in the legs, was referred for electromyography (EMG) and was diagnosed with peripheral polyneuropathy. A few days later, he developed sudden ataxia, dizziness, and diplopia. The neurologic examination revealed nystagmus and ophthalmoplegia, and the FLAIR brain MRI showed symmetrical high signal intensity lesions in the cerebellar dentate nucleus, midbrain, tegmentum around the periaqueductal gray matter, and tectum. After administering intravenous thiamine and stopping the metronidazole therapy, he recovered from the ophthalmoplegia and ataxia. Brain MR showed complete recovery within 3 weeks; however the EMG remained abnormal for a further 6 months, although the symptoms were almost completely resolved by this time.