Title: Metronidazole Induced Encephalopathy: Imaging of an Unusual Side Effect
Authors: Dr Abhishek Jain, Dr Rajesh Shanklesha, Dr Yadav Shashibala Jayanarayan, Dr Bhakti Yeragi, Dr Gayathri Achuthan
DOI: https://dx.doi.org/10.18535/jmscr/v5i1.107
Abstract
Purpose: Metronidazole is one of the most common drug routinely prescribed for anaerobic and helminthic infections. It is commonly used to treat amebiasis, giardiasis, trichomonas, H.pylori and clostridial infections. Minor side effects like nausea, vomiting, metallic taste in the mouth, headache and abdominal pain may be seen after oral administration. Intravenous administration may cause thrombophlebitis. Rare serious side effects like neutropenia, leukopenia, central nervous system toxicity and peripheral neuropathy can be seen after prolonged and high dose treatment with metronidazole. Many of the times this metronidazole induced complication of central nervoussystem toxicity is under diagnosed due to difficulty in establishing the diagnosis. We here report acase of metronidazole induced encephalopathy and discuss its neuro imaging findings.
Case Report: A 50 year old male presented with history of difficulty in walking, mental confusion, slurred speech and double vision. History revealed that he was prescribed metronidazole 50 days back which he has been taking since then (cumulative dose - approximately 60 grams). MRI showed bilaterally symmetrical T2/FLAIR hyper-intensities in dentate nuclei. Other differential diagnosis like wernicke’s encephalopathy was ruled by estimation of serum thaimine levels. Metronidazole was discontinued immediately. After discontinuation of metronidazole patient starting improving clinically. A follow up MRI after 20 days of discontinuation of metronidazole showed complete resolution of altered signal intensity areas involving dentate nuclei.
Conclusion: Though rare, metronidazole-induced encephalopathy, is a serious but potentially reversible side effect of prolonged and high dose intake of metronidazole. Acute central nervous system toxicity caused by metronidazole may closely mimic wernicke’s encephalopathy. Characterstic neuro imaging findings along with normal thiamine levels confirm the diagnosis of metronidazoleinduced encephalopathy.
Keywords: Metronidazole, Encephalopathy, Neuroimaging, Dentate nuclei, Serum thiamine levels.
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Dr Abhishek Jain
Resident in Radiology
Dept of Radio-Diagnosis, T.N.M.C. & B.Y.L.Nair Charitable Hospital, Mumbai INDIA