Toxic Metronidazole-Induced MRI Changes

Abstract

OBJECTIVE: To report a case of changes documented by magnetic resonance imaging (MRI) of the head probably due to accumulation of metronidazole in a patient with liver dysfunction. CASE SUMMARY: A 34-year-old Hispanic man with cirrhosis and hepatitis C being treated with metronidazole for Bacteroides fragilis meningitis and bacteremia developed ataxia, disorientation, and peripheral neuropathy. An MRI at the time meningitis was diagnosed was negative. After the patient received >60 g of metronidazole, an MRI revealed increased signal intensity below, behind, and lateral to the fourth ventricle. Concomitant metronidazole serum concentration was toxic at 35.1 μg/mL. DISCUSSION: This is the second reported case of metronidazole-induced MRI changes. Metronidazole is known to accumulate in patients with liver dysfunction and can cause peripheral neuropathy and central nervous system (CNS) dysfunction; these effects may take up to two years to completely resolve. CONCLUSIONS: Metronidazole dosages should be reduced in patients with liver dysfunction to prevent the accumulation of metronidazole, which can lead to CNS dysfunction and peripheral neuropathy.