Hemichorea-hemiballismus (HC-HB) is a unilateral, involuntary, random movement disorder that can involve both proximal and distal groups of muscles. It is caused by lesions in the contralateral corpus striatum. The most common aetiology is an acute cerebrovascular event, but infections, drugs, tumours and neurodegenerative disorders can all be implicated. Non-ketotic hyperglycaemia has been identified as a metabolic cause of HC-HB, particularly in elderly female patients with newly diagnosed or poorly controlled diabetes. These patients tend to have a characteristic hyperintense signal in the putamen on T1-weighted MR imaging. Often the movement disorder resolves within days to weeks after correction of the hyperglycaemia, but complete resolution of the radiological signs commonly takes months. An 86-year-old woman with newly diagnosed type-2 diabetes presented with hyperglycaemia-induced right-sided HC-HB and typical contralateral high signal change in the putamen on T1-weighted MR scanning. Her symptoms completely resolved within five days of achieving euglycaemia.
