Rare case of chorea-hyperglycaemia-basal ganglia (C-H-BG) syndrome.

An 83-year-old woman presented with acute-onset haemichorea and haemiballism particularly affecting the left side of the body. She was known to have type 2 diabetes, which was poorly controlled with sitagliptin. She was hyperglycaemic but not ketotic or acidotic. After she was started on insulin and good glycaemic control was achieved, her abnormal movements dramatically improved. MRI of the brain showed a T1-weighted hyperintense lesion on the right basal ganglia, which is typical of chorea-hyperglycaemia-basal ganglia syndrome. Other causes of chorea, for example, Huntington's disease, Sydenham chorea, Wilson's disease, malignancy, systemic lupus erythematosus, haemorrhage/infarction, thyroid dysfunction, drug-induced chorea and antiphospholipid syndrome, were excluded or deemed less likely given her rapid response to achieving near euglycaemia.