Skip to main content

Main menu

  • Home
  • Content
    • Current Issue
    • Ahead of Print
    • Past Issues
    • Supplements
    • Article Type
  • Specialty
    • Articles by Specialty
  • CME/MOC
    • Articles
    • Calendar
  • Info For
    • Manuscript Submission
    • Authors & Reviewers
    • Subscriptions
    • About CCJM
    • Contact Us
    • Media Kit
  • Conversations with Leaders
  • Conference Coverage
    • Kidney Week 2024
    • CHEST 2024
    • ACR Convergence 2023
    • Kidney Week 2023
    • ObesityWeek 2023
    • IDWeek 2023
    • CHEST 2023
    • MDS 2023
    • IAS 2023
    • ACP 2023
    • AAN 2023
    • ACC / WCC 2023
    • AAAAI Meeting 2023
    • ACR Convergence 2022
    • Kidney Week 2022
    • AIDS 2022
  • Other Publications
    • www.clevelandclinic.org

User menu

  • Register
  • Log in

Search

  • Advanced search
Cleveland Clinic Journal of Medicine
  • Other Publications
    • www.clevelandclinic.org
  • Register
  • Log in
Cleveland Clinic Journal of Medicine

Advanced Search

  • Home
  • Content
    • Current Issue
    • Ahead of Print
    • Past Issues
    • Supplements
    • Article Type
  • Specialty
    • Articles by Specialty
  • CME/MOC
    • Articles
    • Calendar
  • Info For
    • Manuscript Submission
    • Authors & Reviewers
    • Subscriptions
    • About CCJM
    • Contact Us
    • Media Kit
  • Conversations with Leaders
  • Conference Coverage
    • Kidney Week 2024
    • CHEST 2024
    • ACR Convergence 2023
    • Kidney Week 2023
    • ObesityWeek 2023
    • IDWeek 2023
    • CHEST 2023
    • MDS 2023
    • IAS 2023
    • ACP 2023
    • AAN 2023
    • ACC / WCC 2023
    • AAAAI Meeting 2023
    • ACR Convergence 2022
    • Kidney Week 2022
    • AIDS 2022
The Clinical Picture

Metronidazole-induced encephalopathy: Symmetrical hyperintensity on imaging

Hiroki Matsuura, MD, Takashi Katayama, MD and Kentaro Deguchi, MD, PhD
Cleveland Clinic Journal of Medicine December 2021, 88 (12) 651-652; DOI: https://doi.org/10.3949/ccjm.88a.21007
Hiroki Matsuura
Department of General Internal Medicine, Okayama City Hospital; Department of General Internal Medicine, Okayama City Senoo Hospital, Okayama, Japan
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: [email protected]
Takashi Katayama
Department of Internal Medicine, Okayama City Senoo Hospital, Okayama, Japan
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Kentaro Deguchi
Department of Neurology, Okayama City Hospital, Okayama, Japan
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading

An 83-year-old woman with mild hypertension and hypothyroidism was admitted to our hospital with acute pyelonephritis. She was treated with ampicillin plus sulbactam for 10 days with a good response while she was under rehabilitation receiving physical and speech therapy. However, she suddenly experienced fever, abdominal pain, and severe watery diarrhea. A stool sample was positive for Clostridioides difficile (C difficile) antigen and toxins, and she was prescribed metronidazole 1,500 mg/day for 4 weeks for gastrointestinal symptoms due to C difficile infection

Although the patient’s gastrointestinal symptoms improved, she later presented with an acute onset of dysphagia, nausea, vomiting, dizziness, and progressively altered mental status. Her vital signs were stable. Physical findings revealed no nuchal rigidity or meningeal irritation. However, neurologic examination showed dysarthria, minimal horizontal nystagmus, and unsteady gait. Results of laboratory testing were unremarkable.

Computed tomography showed moderate atrophy without cerebral bleeding. Magnetic resonance imaging (MRI) showed symmetrical T2-hyperintensity in the tectum of the midbrain, pontine tegmentum, and dentate nuclei indicating parenchymal vasogenic edema (Figure 1). Based on the characteristic imaging finding and the clinical history, we made a diagnosis of metronidazole-induced encephalopathy and immediately stopped the metronidazole therapy. After metronidazole was stopped, her neurologic symptoms improved gradually without remission.

Figure 1
  • Download figure
  • Open in new tab
  • Download powerpoint
Figure 1

(A) T2 fluid-attenuated inversion recovery (T2-FLAIR) on MRI shows typical symmetrical hyperintensity in the dentate nuclei of the cerebellum, reflecting vasogenic edema (white arrowheads). (B) T2-FLAIR MRI shows hyperintensity in the tectum of the midbrain (yellow arrowhead). (C) Diffusion-weighted MRI shows hyperintensity in the splenium of the corpus callosum, indicating restricted diffusion or cytotoxic edema (red arrowhead).

METRONIDAZOLE AND NEUROTOXICITY

Metronidazole-induced encephalopathy is a relatively rare central nervous system disorder, associated with prolonged duration and high cumulative doses of metronidazole.1 Metronidazole is commonly used to treat a wide variety of infection-associated diseases, including pelvic inflammatory disease, bacterial vaginosis, intra-abdominal abscess, amebiasis, giardiasis, and C difficile. However, metronidazole has been reported to be inferior to vancomycin particularly for patients with severe cases of C difficile infection.2

The mechanism of neurotoxicity due to metronidazole is unknown. It is thought that metabolites of metronidazole may bind to ribonucleic acid and interfere with ribonucleic acid protein synthesis, which can lead to axonal degeneration.3 Neurologic symptoms of metronidazole-induced encephalopathy vary widely among individual patients but can include cognitive deterioration, peripheral neuropathy, weakness, dizziness, vertigo, nausea, vomiting, headache, sensory loss, and seizures.4

A characteristic MRI finding in patients with metronidazole-induced encephalopathy is bilateral involvement of the cerebellar dentate nuclei.5 However, this is also seen in other neurologic disorders such as Wernicke encephalopathy and isoniazid or methyl bromide toxicity. Thus, the definitive diagnosis should be based on a combination of the patient’s clinical history, laboratory findings, and imaging results. In most cases, the encephalopathy is reversible and generally improves within a few weeks after metronidazole is stoppped.6 However, a delayed diagnosis can have progressive, irreversible consequences, including death.7 Clinicians should consider metronidazole-induced encephalopathy in a patient presenting with new psychiatric and neurologic symptoms and signs, especially in those with cerebellar symptoms who are taking metronidazole.

DISCLOSURES

The authors report no relevant financial relationships which, in the context of their contributions, could be perceived as a potential conflict of interest.

  • Copyright © 2021 The Cleveland Clinic Foundation. All Rights Reserved.

REFERENCES

  1. ↵
    1. Huang YT,
    2. Chen LA,
    3. Cheng SJ
    . Metronidazole-induced encephalopathy: case report and review literature. Acta Neurol Taiwan 2012; 21(2):74–78. pmid:22879116
    OpenUrlPubMed
  2. ↵
    1. Stevens VW,
    2. Nelson RE,
    3. Schwab-Daugherty EM, et al
    . Comparative effectiveness of vancomycin and metronidazole for the prevention of recurrence and death in patients with Clostridium difficile nfection. JAMA Intern Med 2017; 177(4): 546–553. doi:10.1001/jamainternmed.2016.9045
    OpenUrlCrossRef
  3. ↵
    1. Bradley WG,
    2. Karlsson IJ,
    3. Rassol CG
    . Metronidazole neuropathy. Br Med J 1977; 2(6087): 610–611. doi:10.1136/bmj.2.6087.610
    OpenUrlFREE Full Text
  4. ↵
    1. Sonthalia N,
    2. Pawar SV,
    3. Mohite AR, et al
    . Metronidazole-induced encephalopathy in alcoholic liver disease: a diagnostic and therapeutic challenge. J Emerg Med 2016; 51(4):e79–e83. doi:10.1016/j.jemermed.2016.05.038
    OpenUrlCrossRef
  5. ↵
    1. McKinney AM,
    2. Kieffer SA,
    3. Paylor RT,
    4. SantaCruz KS,
    5. Kendi A,
    6. Lucato L
    . Acute toxic leukoencephalopathy: potential for reversibility clinically and on MRI with diffusion-weighted and FLAIR imaging. AJR Am J Roentgenol 2009; 193(1):192–206. doi:10.2214/AJR.08.1176
    OpenUrlCrossRefPubMed
  6. ↵
    1. Sørensen CG,
    2. Karlsson WK,
    3. Amin FM,
    4. Lindelof M
    . Metronidazoleinduced encephalopathy: a systematic review. J Neurol 2020; 267(1):1–13. doi:10.1007/s00415-018-9147-6
    OpenUrlCrossRefPubMed
  7. ↵
    1. Groothoff MV,
    2. Hofmeijer J,
    3. Sikma MA,
    4. Meulenbelt J
    . Irreversible encephalopathy after treatment with high-dose intravenous metronidazole. Clin Ther 2010; 32(1):60–64. doi:10.1016/j.clinthera.2010.01.018
    OpenUrlCrossRefPubMed
PreviousNext
Back to top

In this issue

Cleveland Clinic Journal of Medicine: 88 (12)
Cleveland Clinic Journal of Medicine
Vol. 88, Issue 12
1 Dec 2021
  • Table of Contents
  • Table of Contents (PDF)
  • Index by author
  • Complete Issue (PDF)
Print
Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Email Article

Thank you for your interest in spreading the word on Cleveland Clinic Journal of Medicine.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Metronidazole-induced encephalopathy: Symmetrical hyperintensity on imaging
(Your Name) has sent you a message from Cleveland Clinic Journal of Medicine
(Your Name) thought you would like to see the Cleveland Clinic Journal of Medicine web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Metronidazole-induced encephalopathy: Symmetrical hyperintensity on imaging
Hiroki Matsuura, Takashi Katayama, Kentaro Deguchi
Cleveland Clinic Journal of Medicine Dec 2021, 88 (12) 651-652; DOI: 10.3949/ccjm.88a.21007

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
Metronidazole-induced encephalopathy: Symmetrical hyperintensity on imaging
Hiroki Matsuura, Takashi Katayama, Kentaro Deguchi
Cleveland Clinic Journal of Medicine Dec 2021, 88 (12) 651-652; DOI: 10.3949/ccjm.88a.21007
Twitter logo Facebook logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Linkedin Share Button

Jump to section

  • Article
    • METRONIDAZOLE AND NEUROTOXICITY
    • DISCLOSURES
    • REFERENCES
  • Figures & Data
  • Info & Metrics
  • PDF

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • No citing articles found.
  • Google Scholar

More in this TOC Section

  • Tinea incognito
  • Prolonged venous filling time and dependent rubor in a patient with peripheral artery disease
  • Sarcoidosis with diffuse purplish erythematous plaques on the hands
Show more The Clinical Picture

Similar Articles

Subjects

  • Gastroenterology
  • Geriatrics
  • Hepatology
  • Imaging
  • Neurology

Navigate

  • Current Issue
  • Past Issues
  • Supplements
  • Article Type
  • Specialty
  • CME/MOC Articles
  • CME/MOC Calendar
  • Media Kit

Authors & Reviewers

  • Manuscript Submission
  • Authors & Reviewers
  • Subscriptions
  • About CCJM
  • Contact Us
  • Cleveland Clinic Center for Continuing Education
  • Consult QD

Share your suggestions!

Copyright © 2025 The Cleveland Clinic Foundation. All rights reserved. The information provided is for educational purposes only. Use of this website is subject to the website terms of use and privacy policy. 

Powered by HighWire