A Case of Metronidazole-Induced Encephalopathy: Atypical Involvement of the Brain on MRI

The brain is susceptible to toxicity associated with various drugs and chemical agents. Along with heavy alcohol abuse, which results in chronic or acute brain damage, innumerable other drugs have been reported to induce toxic encephalopathy. Imaging workup plays an important role in the diagnosis of most toxic diseases. Those diseases usually appear in a symmetric fashion, especially with the involvement of the deep gray nuclei and cerebral cortex. Radiologists should be able to recognize and suggest a potential diagnosis of toxic encephalopathy, since early withdrawal of the chemical agents halts the progression of neuropathy and improves clinical prognosis. Metronidazole-induced encephalopathy is a rare form of toxic encephalopathy associated with the use of metronidazole (1) and typically shows symmetric involvement of the dentate nucleus of the cerebellum (2). Metronidazole is one of the most widely-used treatments for anaerobic infection, Crohn’s disease, antibioticsassociated diarrhea, or clostridium difficile-associated disease (2, 3). Due to its relatively low cost and availability in either oral or intravenous forms, as well as its rapid antibacterial effectiveness, metronidazole is considered to be the gold standard antibiotic agent with anaerobic activity. Metronidazole also has good cellular penetration, as well as cerebrospinal fluid and central nervous system penetration, thereby having notable effectiveness in the treatment of anaerobic brain abscess (2). It is generally safe at appropriate dosages, but it can induce neurologic complications, especially when the dose exceeds 2 g/day, or when a cumulative dose of 21-135 g has This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Received: May 7, 2018 Revised: June 11, 2018 Accepted: June 23, 2018