A Teenage Girl With Altered Mental Status and Sinus Tachycardia

A previously healthy 13-year-old adolescent girl presented with loss of consciousness, slurred speech, abnormal upper extremity movements, and progressive difficulty walking. She developed headache the morning of presentation that was then followed by slurred speech, flexion of her upper extremities, and then loss of consciousness. Her examination was remarkable for sinus tachycardia, unresponsiveness, and repeated upper extremity movements. She was intubated for airway protection and extubated on hospital day 2 when her mental status improved. She reported blurry vision and urinary retention initially which improved throughout hospitalization. Her mental status returned to baseline by hospital day 5, and her heart rate normalized on hospital day 10. Comprehensive drug screen returned positive for cyclobenzaprine (Flexeril, Amrix). Cyclobenzaprine overdose is characterized by anticholinergic symptoms. Despite chemical similarity to tricyclic antidepressants, ventricular dysrhythmias are uncommon.