Acquired hemichorea secondary to hyponatremia: a case report

Abstract

Introduction: Chorea is a movement disorder characterized by involuntary, random and irregular movements. In the emergency department, the most common causes of chorea are cerebrovascular disorders, but other conditions may also play an important role. The aim is to present a rare case of acquired hemichorea secondary to hyponatremia by reviewing the patient’s records. Case report: A 73-year-old female patient with a history of arterial hypertension, dyslipidemia, active smoking, and heart failure, taking enalapril, hydrochlorothiazide, furosemide and simvastatin, was admitted to the emergency department after falling from standing height and hitting her head, also presenting choreic movements in the right side of her body. The patient started amitriptyline for chronic low back pain in the last month and had been experiencing apathy and weight loss since; the choreic movements had started a week before admission and had progressively worsened. On admission, the patient presented with fluctuating level of consciousness and hemichorea. Complementary evaluation showed leukocytosis and hyponatremia (117 mg/ dL); magnetic resonance imaging of the brain showed diffuse brain atrophy without any other findings compatible with hemichorea and the lumbar puncture did not reveal any additional findings; a pulmonary infection was detected by the chest computed tomography. The patient was treated for pulmonary infection and hyponatremia. Haloperidol was started, but the chorea was fully solved after hyponatremia correction over the next few days and did not return after haloperidol weaning. Discussion: We presented the case of a 73-year-old woman with acquired hemichorea secondary to hyponatremia, which resolved completely after the metabolic disorder was corrected. Although this condition has been described, its incidence remains unclear, as few cases have been reported.