From Treatment to Toxicity: Metronidazole-Induced Encephalopathy in a 79-Year-Old Woman.

Metronidazole is a commonly used antibiotic effective against anaerobic bacterial and protozoal infections. While generally well tolerated, it is associated with potential neurotoxic effects, including metronidazole-induced encephalopathy (MIE), especially in elderly patients or those with hepatic impairment. We report the case of a 79-year-old woman with a significant medical history who developed neurological symptoms following metronidazole treatment. Initially treated with broad-spectrum antibiotics, she showed limited response, prompting the addition of metronidazole to address suspected amebic infections alongside ongoing therapy with meropenem. Although effective in reducing the abscess size from 12 to 5 cm, the patient subsequently experienced altered mental status and cognitive decline. MRI findings were consistent with MIE. Upon discontinuation of metronidazole, the patient demonstrated notable recovery in cognitive function, confirming the diagnosis and emphasizing the importance of recognizing MIE in at-risk populations. This case underscores the need for careful monitoring and early recognition of neurological complications associated with metronidazole therapy, particularly in older patients or those with comorbidities. Increased awareness among healthcare providers is essential to optimize patient outcomes and prevent unnecessary suffering.