LAUSR

Dear Editor: Chorea originates from dysfunctional neuronal networks interconnecting the basal ganglia and frontal cortical motor areas. Hemichorea-hemiballismus (HCHB) is a rare movement disorder that has been traditionally believed to involve the corresponding contralateral basal ganglia and related circuits [1]. Organic brain lesions (e.g., cerebrovascular events, demyelinating disease, and vasculitis) and metabolic disorders (e.g., hyperglycemia, infection, and medications) can cause HCHB [1]. Of all the etiologies, drug-induced chorea represents one of the most common types of chorea in adults [2]. We describe a patient with an acute episode of right HCHB possibly caused by long-term overdose of cold syrup (Anticold Relief Pain Extra Solution, Chinese brand name is 克風邪). A 79-year-old Taiwanese woman with a history of hypertension visited the emergency department with an acute event of right-sided involuntary movements for 2 days. These involuntary movements continued throughout the day but ceased during sleep. They could be partially controlled by her will but could not be relieved by touch or a specific posture. She had no fever, limb numbness or weakness, altered consciousness, or urinary or fecal incontinence. Additionally, she did not experience a preceding trauma and did not have a similar episode before. None of her family members had hereditary neurological diseases. While the patient was further interviewed about her drug history, she reported that she chronically overdosed (30 ml per day) on over-the-counter cold syrup (克風邪) because of longterm dizziness and had been taking an even higher dose of cold syrup than before for the last week. The recommended dose of the cold syrup is 12 ml per day. On neurological examination, we observed rapid, random, non-patterned, high-amplitude, violent, flinging, and flailing involuntary movements of her right limbs, suggesting rightsided HCHB. Results of the rest of the neurological and physical examinations were unremarkable. Results of laboratory studies, including the complete blood count, serum electrolyte level, urinalysis, creatinine level, liver function test, bilirubin level, blood glucose level, thyroid function, serum tests for autoimmune disease, heavy metal level, serum tumor marker levels, and cerebrospinal fluid examination, were all within normal limits. Findings of imaging studies, including brain computed tomography (CT) and magnetic resonance imaging (MRI), were within normal limits. However, electroencephalography revealed diffuse cortical dysfunction. The Tc-99methyl cysteinate dimer brain perfusion study (single-photon emission computed tomography [SPECT]) was performed 11 days after symptom onset when the involuntary movements were still present, and it showed relative hyperperfusion over the left basal ganglia. On the basis of the strong temporal relationship and exclusion of other causes of involuntary movement, a diagnosis of cold syrup–induced HCHB was made. We stopped the use of cold syrup and then started oral quetiapine (12.5 mg daily) to treat HCHB at 5 days after symptom onset. HCHB lasted about 2 weeks and resolved at 8 days after the initiation of quetiapine therapy.We suspended quetiapine therapy 1month later, and HCHB did not recur during the 1-year follow-up. Chorea or hemichorea can be caused by medications that affect the central nervous system [2]. Several medications, including L-dopa, dopamine agonists, anticonvulsants, benzodiazepines, and antipsychotics, have been reported to cause choreiform movements [2]. Zolpidem, a popular nonbenzodiazepine sedative, was recently reported to induce HCHB [3]. 克風邪 is also a popular over-the-counter cold syrup in Taiwan for treating pain, fever, and nasal congestion. * Li-Min Liou [email protected]