RATIONALE: Hemichorea-hemiballism, a rare manifestation of non-ketotic hyperglycemia, characterized by involuntary arrhythmic motions involving one side of the body, results from focal lesions in the contralateral caudate nucleus and putamen. Hyperkinetic disorders can be complications of uncontrolled diabetes mellitus and should not be ignored. PATIENT CONCERNS: We present the case of a 39-year-old woman who presented to the emergency department with a 3-day history of left-sided hemichorea-hemiballism. She had type 2 diabetes mellitus with poor control and maintenance of regular hemodialysis. DIAGNOSES: The patient was diagnosed as hyperglycemia, normal ketone body and hemichorea-hemiballism based on laboratory examination, computed tomography (CT) scan, and brain magnetic resonance image (MRI). INTERVENTIONS: Intensive glycemic control via insulin injection was prescribed for correction of hyperglycemia. OUTCOMES: The unilateral involuntary movements subsided progressively over four weeks. The patient's hemichorea had completely resolved at the three-month follow-up. LESSONS: This unusual clinical presentation is often accompanied by severe hyperglycemia. Appropriate blood glycemic control is important. If physicians recognize and provide early treatment for this disease, it is usually treatable and has a good prognosis.
