Uncontrolled hyperglycaemia: a reversible cause of hemichorea-hemiballismus.

Hyperosmolar hyperglycaemic state (HHS) an acute complication of diabetes mellitus, can be associated with neurological involvement ranging from seizures, involuntary movements to reversible focal neurological deficits without any structural lesions. We report a 71-year-old woman, a known case of type 2 diabetes mellitus who presented with the sudden onset of hemichorea-hemiballismus. On investigations she had hyperglycaemia and urinary tract infection. Achievement of euglycemia with insulin therapy resolved the involuntary movements completely. This highlights the fact that HHS is an uncommon but easily treatable cause of recent onset unilateral hemichorea-hemiballismus.