Acute chorea in the diabetic nonketotic hyperosmolar state

Chorea–ballismus in diabetic patients with uncontrolled hyperglycaemia is often associated with a hyperintense signal on T1-weighted MRI in the basal ganglia. We report two patients: a 62-year-old woman with type II diabetes mellitus and the nonketotic hyperosmolar state who presented with acute generalised chorea, and a 72-year-old man with right hemichorea beginning one week after correction of severe hyperglycaemia and hyperosmolality as the presenting manifestation of type II diabetes. In both patients, chorea did not improve after correction of dehydration and hyperglycaemia, but responded within one week to treatment with low-dose haloperidol and tetrabenazine. Chorea in this setting is thought to be due to the effect of hyperglycaemia, hyperosmolarity and reduced perfusion on striatal metabolism, possibly in association with underlying focal cerebrovascular disease which leads to striatal dysfunction, astrocytosis, and hyperkinesia. We review 21 patients with this syndrome published from 2001 onwards, and provide a detailed discussion of pathogenesis, clinical features, imaging and prognosis. As demonstrated by our patients, the disorder can be the presenting symptom of DM; it may be unilateral or bilateral; and MRI findings correlate well with the clinical pattern. HCHB improves with correction of the metabolic abnormality in many patients, but some may need neuroleptic therapy, and a few have a poor response. The generally favourable outcome underlines the need for correct diagnosis and adequate management of the metabolic problem underlying the often dramatic onset of chorea.