Hyperglycemic Chorea

Case Presentation

A 72-year-old woman with previously well-controlled type 2 diabetes presented to the hospital with altered mental status and new-onset involuntary bilateral arm movements. Physical examination revealed choreiform movements of the left upper extremities without any loss of sensation or focal neurologic deficits (Video 1). Laboratory workup revealed a glucose level of 1113 mg/dL (reference range [RR], 70-140 mg/dL), sodium level of 136 mEq/L (RR, 135-145 mEq/L), calculated serum osmolarity level of 357 mOsm/kg (RR, 275-295 mOsm/kg), bicarbonate level of 8 mEq/L (RR, 20-30 mEq/L), anion gap level of 35 mEq/L (RR, 7-16 mEq/L), hemoglobin A1C level of >14% (RR, <5.7%), and thyroid-stimulating hormone level of 1.03 μU/mL (RR, 0.30-4.20 μU/mL). Brain magnetic resonance imaging showed periventricular and subcortical white matter fluid attenuated inversion recovery signal abnormalities suggestive of moderate chronic white matter microvascular ischemic changes. There was no acute infarct, intracranial hemorrhage, or intracranial mass lesion or focal mass effect. She was discharged on a basal bolus insulin regimen. Three months after the encounter, her hemoglobin A1C level improved to 5.8%, and her chorea resolved (Video 2).

What is the diagnosis?

Answer

This clinical presentation is characteristic for hyperglycemic chorea secondary to poorly controlled type 2 diabetes mellitus, also referred to as diabetic striatopathy.¹ It is characterized by hyperglycemia with unilateral or bilateral chorea, which frequently involves the arms and legs, and occurs during an episode of nonketotic hyperglycemia.² Although the exact pathogenesis of this presentation is unknown, a suggested explanation is neurotransmitter imbalance between dopamine and gamma-aminobutyric acid. The prevalence is estimated to be approximately 1 in 100 000; however, this may represent an underestimation due to the lack of epidemiologic data.¹ The disorder is more prevalent in women in the sixth or seventh decade of life.³ Characteristic imaging findings are a hyperintensity signal of the basal ganglia with sparing of the internal capsule on T1-weighted magnetic resonance imaging; however, neuroimaging may not always show these lesions.¹ Our initial differential diagnoses included a basal ganglia ischemic/hemorrhagic stroke, an underlying central nervous system neoplasm, and thyrotoxicosis-associated hyperkinetic movements. It is also important to consider hereditary neurodegenerative diseases, drug toxicities, and vitamin deficiencies.⁴ A detailed review of the patient’s history revealed a similar presentation of hyperglycemia and abnormal arm movement 2 years prior. Recurrence of choreiform movements during episodes of hyperglycemia and resolution with improved glycemic control confirmed the diagnosis of diabetic striatopathy. Treatment includes optimization of blood glucose control, and the chorea resolves with improvement in glycemic control. However, recurrence is observed in 18.2% of patients, as noted in our patient.² Three months after discharge on a basal bolus insulin regimen, her hemoglobin A1C level improved to 5.8%, and her chorea resolved. Hyperglycemic chorea is a rare neurologic manifestation and should be considered in patients with poorly controlled type 2 diabetes mellitus presenting with new-onset choreiform movements and increased serum glucose levels, with or without the typical neuroimaging findings. The hallmark of treatment includes prompt diagnosis and optimal glycemic management for reversal of symptoms.

Disclosure

The authors have no conflicts of interest to disclose.