A sixty-three year old female with a 13-year history of type 2 diabetes treated with oral agents alone presented with sudden onset of left-sided hemiballismus. She had omitted her treatment for a number of months prior to presentation and HbA1C was 14.9%. A magnetic resonance imaging (MRI) scan of her brain showed a high signal on diffusion-weighted and hyperintensity on T1 weighted images in the right medial lentiform nucleus and head of caudate. Blood tests indicated severe hyperglycemia (serum glucose 26.2 mmol/L). She was diagnosed with hyperglycemia induced chorea-ballismus (HICB). After prompt treatment of her hyperglycemia with insulin, her hemiballismus resolved completely within 10 days.
HICB is a rare complication of hyperosmolar hyperglycemic state (HHS). It is characterized by a sudden onset of uni- or bilateral choreatic or ballistic movements in the context of severe hyperglycemia. There is a predilection for elderly women and occurs more frequently in Asians, suggesting a genetic susceptibility. Radiologically, HICB is associated with high signal intensity in the basal ganglia on T1 weighted sequences with the putamen being most frequently affected. Several mechanisms have been suggested including hyperglycemia-induced depletion of cerebral gamma-aminobutyric acid, activation of inflammatory cascades and regional hypoperfusion as a result of increased cerebrovascular resistance and hyperviscosity. However, the pathophysiology remains elusive. Treatment of the hyperglycemia results in quick resolution of symptoms in most cases.
In patients presenting with unexplained hemiballismus, hyperglycemia should be considered as it is an easily treatable cause leading to quick recovery if treated promptly.