SUMMARYHyperosmolar 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. BACKGROUND

A 47-year-old Asian Indian woman presented with uncontrolled hyperglycaemia and osmotic symptoms despite multiple oral antidiabetic medications and insulin. She had a history of recurrent oral ulcers, profound weight loss, and intermittent fever for one and a half years before the presentation. She had severe acanthosis nigricans, although her body mass index (BMI) was 14.6 kg/m 2. Her blood glucose remained uncontrolled despite very large dosages of intravenous insulin (more than 12,000 units daily). Evaluation for possible underlying collagen vascular diseases and malignancies were negative. Her serum insulin levels were high. She tested negative for anti-insulin antibodies but positive for anti-insulin-receptor antibodies. She improved with a pulse dose of intravenous methylprednisolone but relapsed within one month. A second pulse dose was given following which a complete remission of diabetes and regression of acanthosis was observed. Type B insulin resistance, a rare cause of severe insulin resistance, may respond favourably to immunosuppressive therapy with high-dose methylprednisolone.