Hyperglycemia-Induced Involuntary Movements: 2 Case Reports and a Review of the Literature

ABSTRACT Objective: Autonomic and peripheral neurologic manifestations of hyperglycemia are commonly seen in clinical practice; acute hyperglycemia-induced involuntary movements (HIIM) are rarer and less well known. In this article we describe 2 patients with HIIM and review the scientific literature to better characterize the clinical and pathophysiologic features of these disorders. Methods: A literature search was performed using the PubMed database. Whenever possible, the most recent publication on a topic was utilized, with a 20-year cutoff time since publication. Articles were selected based on the quality of presented data or citations utilized. Results: HIIM can present in a variety of ways including seizures, hemichorea-hemiballismus (HCHB) and, very rarely, tremor. While HIIM are more commonly seen in patients with long-standing, uncontrolled diabetes, they can also be the initial presentation of diabetes. The precise pathophysiology of HIIM remains unknown; however, at least for HCHB, it is hypothesized that hyperglycemia increases the metabolism of the inhibitory neurotransmitter gamma aminobutyric acid (GABA), thereby lowering the seizure threshold. It may also cause regional cerebral vascular insufficiency. Treatment of HIIM differs from that for seizures and other movement disorders in that it relies primarily on glucose control. Conclusion: It is important to recognize hyperglycemia as a cause of involuntary movements so as to provide timely treatment for potentially life-threatening conditions such as hyperosmolar nonketotic hyperglycemia and diabetic ketoacidosis. The proper diagnosis of HIIM can avoid unnecessary and often ineffective initiation of antiepileptics or other medications. Abbreviations: HCHB hemichorea-hemiballismus HIIM hyperglycemia-induced involuntary movements GABA gamma aminobutyric acid EPC epilepsia partialis continua MRI magnetic resonance imaging NKH nonketotic hyperglycemia