Metronidazole-Induced Encephalopathy in a Patient With Metastatic Cancer

Metronidazole-induced encephalopathy (MIE) is a rare adverse effect from long-term metronidazole use. We describe a patient with metastatic cancer and complicated abscesses on long-term antibiotics who presented to the emergency department with acute encephalopathic features including reported weakness and confusion. Physical examination was remarkable for chronic right-sided weakness from a previous stroke and reported abnormal right-sided finger-to-nose testing, which may have been due to weakness from his prior stroke. Head CT was non-contributory, and brain MRI showed bilateral edema in cerebellar dentate nuclei, suggestive of MIE. We recommend having a low threshold for brain MRI in patients on long-term metronidazole to rule out other diagnoses and, in patients with lasting neurologic deficits, early neurology and palliative care involvement to improve quality of life.