Hemichorea after hypoglycemic episodes with negative MRI findings in an elderly woman with poorly controlled type 2 diabetes mellitus: a case report

BACKGROUND: Diabetic chorea appears during the course of poorly-controlled diabetes. While chorea associated with diabetes mellitus usually occurs during hyperglycemic episodes, hypoglycemia can also cause diabetic chorea. Brain magnetic resonance imaging (MRI) is useful for evaluating the pathogenesis of diabetic chorea. However, several diabetic chorea cases have reportedly not shown abnormal high-intensity in the putamen and striatum on T1-weighted images. CASE PRESENTATION: We report a 74-year-old woman who was admitted to our hospital for treatment of poorly-controlled type 2 diabetes mellitus. Intensified insulin treatment gradually normalizeed blood glucose, but on the 19th hospital day, after a blood glucose measurement of 49 mg/dL, she showed hemichorea of the left face, shoulder, arm and leg. MRI revealed no abnormalities of either the putamen or the striatum on T1-weighted images. She was treated with dopamine receptor antagonists, which alleviated her hemichorea symptoms and allowed discharge from the hospital. 1 year after the first hospitalization, she had to be readmitted because her glycemic control had markedly deteriorated. Glycemic control improved rapidly, and, because hemichorea did not recur, the dopamine receptor antagonists were stopped. 1 month later, however, hemichorea recurred. She resumed taking the dopamine receptor antagonists, resulting in immediate disappearance of the hemichorea. CONCLUSIONS: We herein describe a rare case of diabetes-associated hemichorea occurring after hypoglycemic episodes without abnormal high-intensity findings in the basal ganglia on T1-weighted images. The hemichorea relapsed with cessation of dopamine receptor antagonists. This case also underscores the importance of longitudinal assessment and treatment for hemichorea after hypoglycemic episodes, even in the absence of MRI findings, in elderly diabetic patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12883-019-1334-2) contains supplementary material, which is available to authorized users.