[Metronidazole-induced encephalopathy: description of a case with radiological and anatomopathological findings]

Metronidazole is a widely known and used antibiotic. In exceptional cases, an encephalopathy with characteristic lesions on magnetic resonance imaging (MRI), usually located in the cerebellum and splenium of the corpus callosum, may be an adverse effect. The incidence and pathogenesis are unknown. The suspension of the treatment usually resolves the symptoms and normalizes the MRI in a few weeks. Due to the usual good prognosis, the anatomopathological findings are exceptional. We present a clinical case with the radiological findings suggestive of metronidazole-induced encephalopathy and, exceptionally, we provide the anatomopathological findings.

A 72 years-old woman with severe Crohn's disease who, months after starting treatment with metronidazole, presented a slowly progressing bradypsychia and difficulty walking until she came to coma. In MRI it showed hyperintense images in T2 in the corpus callosum, red and dentate nuclei. He improved by stopping metronidazole but later developed sepsis and died. At autopsy, softening of the red nucleus was observed and, microscopically, cell necrosis and demyelination.

With the publication of the clinical, radiological and anatomopathological information of our case we intend to promote the knowledge of this infrequent treatable cause of subacute encephalopathy and provide data that help to clarify its pathogenesis.