Persistent chorea triggered by hyperglycemic crisis in diabetics.
Five female patients developed chorea concurrent with, or shortly after a hyperglycemic episode (admission glucose values 500-1,000 mg/dL). In four of these five patients, there was no prior history of diabetes mellitus. The chorea continued despite correction of blood glucose and persisted to the time of last follow-up, 6 months to 5 years later. The chorea developed subacutely over 2 days to 1 month and was generalized in one, unilateral in three, and involved right > left lower extremity in the other; the severity initially reached ballistic proportions in two. Associated clinical features were nil in four of these patients, but cognitive impairment and personality change occurred in one. The histories and laboratory studies identified no predisposing factors other than the hyperglycemia. The chorea was sufficiently troublesome to require administration of neuroleptic medication in all five cases. Four of the five cases had high signal intensity within basal ganglia on T1-weighted magnetic resonance (MR) imaging, as has previously been described; however, this was not seen in one case (who had the most severe clinical condition). Most previously described cases have involved a reversible clinical syndrome, in contrast to our patients. The pathogenic mechanisms remain uncertain.