Metronidazole-Induced Encephalopathy in a Patient with End-Stage Liver Disease

Purpose. Metronidazole-induced encephalopathy (MIE) has been rarely reported. We report a case in a patient with end-stage liver disease (ESLD). Summary. A 63-year-old male with ESLD secondary to hepatitis C virus presented with progressively worsening fatigue, slurred speech, aphasia, vomiting, and left-sided facial droop after completing a 2-week course of metronidazole for recurrent Clostridium difficile-associated diarrhea. He completed a previous course of metronidazole 3 weeks prior to presentation. He is on the liver transplant waiting list and has known hepatic encephalopathy. MRI revealed hyperintense T2 signals involving the bilateral dentate nuclei, inferior colliculi and splenium of the corpus callosum, and increased diffusion restriction at the splenium of the corpus callosum. His neurological function improved over the next several days. He underwent liver transplantation 6 days after admission. A follow-up MRI 6 weeks after presentation revealed resolution of abnormalities; however, paresthesias persisted 6 months after MIE diagnosis. Conclusion. An ESLD patient with hepatic encephalopathy developed MIE after a relatively short course of metronidazole. Metronidazole has been shown to accumulate in patients with ESLD. Increased awareness for neurotoxicity when using metronidazole in ESLD patients is warranted, especially in those with potentially confounding hepatic encephalopathy. 1. Introduction Metronidazole-induced encephalopathy has been identified as an adverse effect of prolonged metronidazole use; however, there have only been limited cases reported to date [1–12]. Metronidazole is commonly prescribed for Clostridium difficile infections, but may also be used in the management of anaerobic bacterial infections, protozoal infections, Helicobacter pylori gastritis, noninfectious colitis, and hepatic encephalopathy. While generally well tolerated, the most common adverse drug reactions observed in patients undergoing treatment with metronidazole include nausea, dysgeusia, anorexia, and abdominal cramping [13]. Neurotoxicity has been rarely reported, with features ranging from headache, incoordination, and ataxia to convulsive seizures, optic neuropathy, peripheral neuropathy, and encephalopathy. While the exact incidence and mechanism of metronidazole-induced encephalopathy (MIE) is not known, most cases in the literature have occurred after long-term, high-cumulative dose treatment with metronidazole. We report a case of MIE that occurred in a patient with end-stage liver disease (ESLD) after a relatively short-treatment course for