Case Presentation: A 62-year-old man with a past medical history of chronic obstructive pulmonary disease (COPD) and intravenous drug abuse presented to the emergency department (ED) with progressive worsening of jerky movements in his right arm and right leg which started about four months before presentation. Six months prior to his presentation, he started to have progressive weight loss and loss of appetite for which he was prescribed cyproheptadine. He denied having hemoptysis, fever, chills, night sweats, or recent travel. He doesn’t take any medication except for cyproheptadine.In the ED, he was afebrile and had a blood pressure of 140/80 mmHg, pulse rate of 70 beats-per-minute, and respiratory rate of 16 breaths-per-minute. On physical examination, he looked cachectic with normal chest, heart, and abdomen examination. Neurological exam was significant for choreiform movements of the right upper and lower extremities. Cranial nerves, strength, sensation, and coordination were all normal on examination. His gait was normal in between the hyperkinetic movement episodes.
Initial laboratory work-up including complete blood count and basic metabolic panel was normal. Chest radiograph revealed a right upper lobe cavity which was confirmed to be an abscess on computed tomography (CT) scan. Bronchoscopy with broncho-alveolar lavage (BAL) was then performed. BAL analysis and blood work-up were negative for tuberculosis, human immunodeficiency virus (HIV), fungal infections, vasculitis, and malignancy. He was started on antibiotics and follow-up imaging demonstrated improvement in the lesion.
During the patient’s hospitalization, and as a work-up for chorea, magnetic resonance imaging (MRI) of the brain and the spine was performed and it was normal. His electroencephalography (EEG) was negative for epileptic activity. Lumbar puncture was performed and cerebrospinal fluid analysis was normal.
Interestingly, his chorea started to improve till complete resolution on day four. Looking retrospectively, and after the extensive work-up which was unrevealing, the only intervention done was stopping his cyproheptadine on admission. Based on this, his chorea was presumed to be a side-effect of cyproheptadine which resolved after stopping the medication.
Discussion: Chorea is a hyperkinetic movement disorder that is characterized by jerky, dance-like involuntary movements flowing from one body part to another. Chorea is either primary (idiopathic, hereditary), or secondary due to vascular nervous system lesions, inflammatory disorders, metabolic derangements, endocrine disorders, infections, and some medications. Cyproheptadine is a histamine-1 (H1) antagonist that is off-label-used to treat decreased appetite. Though cyproheptadine has some side effects, only one case report described chorea as a potential side effect of it. We present another case of this extremely-rare side effect of cyproheptadine.
Conclusions: Cyproheptadine is an anti-histamine medication with anti-serotoninergic and anti-cholinergic properties. It is considered relatively a safe drug; however, clinicians should be aware of its side effect profile, including chorea.