March 2, 2018
A 51-year-old female with alcoholic cirrhosis was treated with oral metronidazole (500mg three times daily) and ceftriaxone (1g daily) for a frontal brain abscess. On day 27 of treatment she presented with slurred speech and difficulty maintaining her balance while walking. She was afebrile and with normal mentation. Physical examination revealed ataxia, dysarthria and horizontal nystagmus. She had no focal weakness or sensory loss. Her laboratory values were in keeping with compensated cirrhosis and there was no leukocytosis.
An urgent brain MRI showed resolution of the frontal abscess. There was no evidence of recent infarction or abscesses elsewhere but there was increased signal intensity in the dentate nuclei bilaterally on T2-weighted and fluid attenuated inversion recovery (FLAIR) images (Image 1 and 2).
Her serum metronidazole level was 110 mcg/ml; drawn 24 hours after her last dose (usual peak concentration: 12 mcg /ml at 2 hours after 500mg oral dose). A diagnosis of metronidazole induced encephalopathy (MIE) was made and the drug was withheld. Her neurological symptoms improved dramatically over a 2-week period.
Which of the following can cause the symmetric increased signal intensity in the dentate nuclei bilaterally on T2-weighted and fluid attenuated inversion recovery (FLAIR) images, as seen in our patient?
A. Wernicke’s encephalopathy
B. Metronidazole Induced Encephalopathy (MIE)
C. Cerebellar abscesses
D. Hepatic Encephalopathy
E. A, B only
F. A, B, C, D
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References:
1. Kim E, Na DG, Kim EY, et al. MR imaging of metronidazole-induced encephalopathy: lesion distribution and diffusion-weighted imaging findings. AJNR Am J Neuroradio. 2007;28:1652–8.
2. Knorr JP, Javed I, Sahni N, Cankurtaran CZ, Ortiz JA. Metronidazole-Induced Encephalopathy in a Patient with End-Stage Liver Disease. Case Reports in Hepatology. 2012;2012:209258.
3. Cheong HC, Jeong TG, Cho YB, et al. Metronidazole-induced encephalopathy in a patient with liver cirrhosis. The Korean Journal of Hepatology. 2011;17(2):157-160.
Author Information:
Ryan Kunjal, MD, is a Resident, Internal Medicine Department, University of Florida Health Jacksonville College of Medicine.
Amie Leon, DO, is a Resident, Internal Medicine Department, University of Florida Health Jacksonville College of Medicine.
Candice Baldeo, MD, is a Resident, Internal Medicine Department, University of Florida Health Jacksonville College of Medicine.
Ria Ramadoo, MD, is a Graduate, University of the West Indies Faculty of Medical Sciences, St Augustine, Trinidad and Tobago.