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Updated: Oct 2, 2025
Nerve Excitability Assessment in Chemotherapy-induced Neurotoxicity
Published on: April 26, 2012
Metronidazole-Induced Toxic Neuropathy With the "Boomerang" Sign: A Case Report
Ritwik Ghosh1, Subhankar Chatterjee2, Mahua Jana Dubey3
1Department of General Medicine, Burdwan Medical College and Hospital, Burdwan, West Bengal.
Background:
Metronidazole has been used to treat a broad range of infections over the decades, and its safety profile has been presumably well studied. However, neurological severe adverse events after prescription and nonprescription use of metronidazole is well recognized but underdiagnosed.
Case Presentation:
We report the case of a 48-year-old Indian man who presented with unremitting symptoms of peripheral neuropathy along with a silent callosal lesion in the splenium ("boomerang" sign). Because he had visited 3 neurologists previously, there were many targeted and nontargeted investigations, which failed to reach an etiological diagnosis and hence to provide relief. The patient was questioned about a potential neurotoxin exposure, and at that point, he said that he had been taking metronidazole for a long time, without any supervision, as an over-the-counter remedy for self-diagnosed "chronic amebiasis." On stopping metronidazole, he recovered gradually. In the sixth month of follow-up, brain magnetic resonance imaging showed disappearance of the callosal lesion and significant improvement in the nerve conduction studies.
Conclusions:
Clinicians should keep metronidazole toxicity in mind while dealing with a case of cytotoxic lesion of the corpus callosum with splenium involvement and peripheral neuropathy.
Insights
Metronidazole can cause severe neurological damage, including peripheral neuropathy and corpus callosum lesions, especially with long-term, unsupervised use. Promptly stopping this medication can lead to significant recovery.
Area of Science:
- Neurology
- Toxicology
Background:
- Metronidazole is widely used for infections, with an assumed safety profile.
- Neurological adverse events from metronidazole are recognized but often underdiagnosed.
Observation:
- A 48-year-old man developed peripheral neuropathy and a splenium corpus callosum lesion ('boomerang' sign).
- Previous investigations by multiple neurologists were inconclusive.
- The patient reported long-term, unsupervised use of metronidazole for self-diagnosed chronic amebiasis.
Findings:
- Discontinuation of metronidazole led to gradual recovery of symptoms.
- Follow-up MRI showed resolution of the callosal lesion.
- Nerve conduction studies demonstrated significant improvement.
Implications:
- Metronidazole toxicity should be considered in cases of peripheral neuropathy with splenium corpus callosum lesions.
- Awareness of this neurotoxicity is crucial for clinicians managing patients with unexplained neurological symptoms.
- Highlights the risks of unsupervised, long-term use of commonly prescribed medications.
