Metronidazole-Induced Cerebellar Toxicity

Abstract

Metronidazole is a very common antibacterial and antiprotozoal with wide usage across the globe, including the least developed countries. It is generally well-tolerated with a low incidence of serious side-effects. Neurological toxicity is fairly common with this drug, however majority of these are peripheral neuropathy with very few cases of central nervous toxicity reported. We report the imaging findings in two patients with cerebellar dysfunction after Metronidazole usage. Signal changes in the dentate and red nucleus were seen on magnetic resonance imaging in these patients. Most of the cases reported in literature reported similar findings, suggesting high predilection for the dentate nucleus in metronidazole induced encephalopathy.

Keywords: Metronidazole; dentate; magnetic resonance imaging; toxicity.

Figure 1.

Multiple axial magnetic resonance imaging of the brain in a 22-year old male on metronidazole presenting with cerebellar symptoms. Axial T2 images (a,b) reveal symmetric areas of increased signal in the dentate (black arrows), the facial (yellow arrows) and the red nuclei (red arrows), bilaterally. Axial fluid attenuated inversion recovery images (c) showing similar changes with restricted diffusion noted on the diffusion-weighted image (d).

Figure 2.

Axial fluid attenuated inversion recovery (a) and T2-weighted images (b) in an 80 year old lady on Metronidazole, presenting with ataxia and gait abnormalities. Symmetric areas of increased T2/fluid attenuated inversion recovery signal noted in the dentate nuclei, bilaterally (black arrows). Follow-up imaging was not performed as there was complete resolution of clinical signs and symptoms.