[Reversible changes on MR images in a patient with metronidazole-induced encephalopathy]

Area of Science:

• Neurology
• Radiology
• Infectious Diseases

Background:

• Brain abscesses require effective antimicrobial treatment, with metronidazole being a common choice.
• Metronidazole, while effective, carries a risk of neurological side effects, including toxicity.
• Understanding the neuroimaging manifestations of metronidazole toxicity is crucial for accurate diagnosis.

Observation:

• A 66-year-old woman treated for a brain abscess developed progressive neurological symptoms, including altered consciousness and cerebellar dysfunction.
• Brain MRI revealed bilateral symmetrical lesions in the splenium of the corpus callosum (SCC), cerebellar dentate nucleus, and inferior colliculus.
• Reduced ADC values and increased lactate in the SCC suggested cytotoxic edema, while other lesions were consistent with vasogenic edema.

Findings:

• Clinical presentation and characteristic MRI findings strongly indicated metronidazole-induced neurotoxicity.
• Discontinuation of metronidazole resulted in rapid clinical improvement and resolution of suspected vasogenic edema.
• The SCC lesion, indicative of cytotoxic edema, showed slower resolution, persisting for up to 40 days.

Implications:

• This case highlights the importance of considering metronidazole toxicity in patients presenting with neurological deficits during treatment.
• Distinct neuroimaging patterns (cytotoxic vs. vasogenic edema) can help differentiate metronidazole toxicity from other neurological conditions.
• Early recognition and management of metronidazole neurotoxicity are essential for favorable patient outcomes.