Case Presentation: A 74-year-old Caucasian male presented to our emergency department with unintentional movements of right arm and right leg for 1 day. He was diagnosed with type 2 diabetes mellitus 20 years ago and is not compliant with his insulin regimen. His medical history is also significant for diabetic neuropathy, hypertension and depression. Physical examination revealed a well-built male with normal higher mental functions and neurological examination. Continuous, large-amplitude jerking and flinging movements involving the right upper and lower extremity was noticed. The movements were present both in proximal and distal joints, and reduced significantly during sleep. On evaluation, initial blood glucose level was 450 mg/dl, with a hemoglobin A1C of 13.6% and serum osmolality of 328 mOsmol/liter. Arterial blood gas did not show acidosis and urine was negative for ketone bodies. Complete blood count, liver function tests, renal function tests, thyroid function tests, infectious and autoimmune panel was negative. Computerized Tomography(CT) brain without contrast was negative for any acute intracranial pathology. Magnetic Resonance Imaging(MRI) brain showed high signal intensity of left lentiform nucleus on T1- weighted images, low signal intensity on T2-weighted images and fluid-attenuated inversion recovery images. He was started on insulin and a low dose of clonazepam and glycemic control was achieved by day 2. The movements completely resolved by forth day and he was discharged home. Two weeks later, we obtained a follow up MRI which showed resolution of the T1 hyperintensity in the left lentiform nucleus.
Discussion: Nonketotic hyperglycemia is a rare cause of hemichorea-hemiballismus. The pathogenesis of this disorder is thought to be related to hyperglycemia-induced perfusion changes in the striatum and ischemic excitotoxicity of GABAergic neurons. MRI brain is the diagnostic modality of choice and typically demonstrates signal changes particularly in the putamen and caudate. The hyperintensity on T1WI sequence is the most consistent finding of the disease; and restricted diffusion in DWI and hypointensity in T2 FLAIR also supports the diagnosis. Symptoms and imaging findings usually resolve upon normalization of glucose levels. In refractory cases, drugs that block postsynaptic dopamine receptors, such as haloperidol or risperidone, can be used.
Conclusions: Nonketotic hyperglycemic hemichorea is a rare disorder characterized by the triad of involuntary movements, striatal abnormalities on neuroimaging, and hyperglycemia in patients with known or previously unrecognized diabetes mellitus. It is important to distinguish this cause from other intracranial pathologies as prompt glycemic control leads to complete resolution of the symptoms and signs.