Diabetic hemiballismus in the context of euglycaemia

An 84‐year‐old white British woman with a background history of type 2 diabetes, Alzheimer's dementia, gout and hypothyroidism presented with a four‐day history of sudden, involuntary left arm and left leg movements. She had venous blood glucose of 4.4mmol/L with normal pH on admission. She had normal inflammatory markers with no signs of acute infection. Initial computed tomography brain imaging showed a known stable meningioma with no acute haemorrhage or infarct. Of note she had an admission, six weeks prior, with falls and raised capillary blood glucose readings. On that admission, her HbA1c was noted to have increased to 146mmol/mol having been 57mmol/mol six months earlier. Her oral hypoglycaemic agents were up‐titrated. There was no documented episode of hyperosmolar hyperglycaemic state. Brain magnetic resonance imaging (MRI with contrast) showed right striatal T1 high signal typical of diabetes‐related hemiballismus. She was treated with tetrabenazine for two weeks which was stopped before discharge as there was complete resolution of involuntary arm and leg movements. Hemiballismus is a rare but well‐known complication of diabetes. It is typically seen in the setting of hyperglycaemia. Our patient presented with hemiballismus while euglycaemic in the setting of recent hyperglycaemia. Copyright © 2021 John Wiley & Sons.