Metronidazole toxicity presenting with acute onset of aphasia and right sided weakness

Metronidazole Induced Encephalopathy Mimicking an Acute Ischemic Stroke Event

Metronidazole induced encephalopathy (MIE), an encephalopathy brought by an antibiotic, is characterized with cerebellar dysfunction, altered mental status and extrapyramidal symptoms. MIE can result in an acute manifestation, but MIE has not been reported as a stroke mimic. An 86-year-old patient undergoing metronidazole therapy for Clostridium difficile enteritis presented to our hospital with sudden disoriented status and motor weakness of the left extremities. Computed tomography (CT) was unrevealing of intracranial hemorrhagic change, and CT angiography did not show any apparent major occlusion or stenosis of the intracranial vessels. However, CT perfusion (CTP) revealed a decrease in peripheral blood flow in the right cerebral hemisphere, and tissue plasminogen activator was administrated for a possible acute ischemic stroke. The findings of follow-up magnetic resonance imaging (MRI) were typical for MIE, revealing areas of hyperintensity on fluid attenuated inversion recovery (FLAIR) signal intensity in the dentate nuclei, the splenium of the corpus callosum, and in the dorsal midbrain. The degree of hyperintensity was stronger in the left dentate nucleus than in the right left dentate on FLAIR and the apparent diffusion coefficient map. The asymmetric findings of the left dentate nucleus on MRI were considered to be responsible for the clinical symptoms and the findings of CTP. We report a rare case of MIE mimicking an acute ischemic stroke, and hypothesize the relationship between the findings of CTP and that of MRI based on the anatomical connection of the dentate nucleus and the cerebral hemisphere.