The syndrome of dyskinesia associated with hyperglycemia and basal ganglia hyperintensity on T1 – weighted MR images is rare and most often affects elderly patients with type 2 diabetes. We report a case of a 79 year-old female patient who presented to the ED with a 12 h history of a left sided hemichoreoathetosis. Laboratory results revealed pronounced nonketotic hyperglycemia [27 mmol/L (486 mg/dL); HbA1c 140 mmol/mol (15 %)] and brain MRI showed bilateral T1 hyperintensity in the basal ganglia, more noticeable on the right side. One week before she had been admitted with a diagnosis of transient ischemic attack consisting in left hemiparesthesia, also with nonketotic hyperglycemia [38.9 mmol/L (700 mg/dL)] and was discharged home with partial correction of her metabolic disturbance. The movement disorder did not improve with adequate glycemic control so haloperidol was started. Six weeks later she was seen on an outpatient basis. She still had minimal residual involuntary movements of the left arm and leg. Laboratory exams revealed a well controlled diabetes mellitus [glycemia 6.0 mmol/L (109 mg/dL), HbA1c 57 mmol/mol (7.4 %)]. In conclusion, the syndrome of dyskinesia associated to hyperglycemia and hyperintensity in the basal ganglia on T1 – weighted MR images is a rare, intriguing and yet incompletely understood complication of diabetes mellitus. The increasing number of reported cases may help to better understand its peculiarities such as the existence of a clear clinical radiological dissociation and to unveil pathophysiological aspects. We suggest the possibility that the metabolic disturbances unmask a previous established asymptomatic striatum vasculopathy.