A 36-year-old man with diffuse large B-cell lymphoma presented with polyneuropathy, and the diagnostic work-up revealed the presence of IgM antibodies against gangliosides with disialosyl residues (GD1b, GD3). He was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone and received high-dose intravenous immunoglobulin for the treatment of neuropathy. After initiating the treatments, the patient's neurological impairment improved dramatically. He currently remains in complete remission without a flare-up of the polyneuropathy. Based upon our experience and other case reports of lymphoma with immune-mediated neuropathy caused by anti-disialosyl ganglioside IgM antibodies, we conclude that determining the anti-ganglioside antibody profile and beginning early treatment should be considered promptly for patients with malignant lymphoma who develop polyneuropathy.

We describe a 36‐year‐old man with metronidazole‐induced encephalopathy in the course of alcoholic liver cirrhosis who developed periodic myoclonus on the head and fixed eye position with ocular myoclonus in the vertical direction. Involuntary movements are rare in patients with metronidazole‐induced encephalopathy, because neurological manifestations of metronidazole‐induced encephalopathy usually include ataxic gait, dysarthria and confusion. Involuntary movements including myoclonus should be considered as the clinical manifestation of metronidazole‐induced encephalopathy. In addition, we review the literature of metronidazole‐induced encephalopathy patients who developed myoclonus with regard to the clinical characteristics.