MSFinals-4879

A 50-year-old woman arrives at the emergency department with symptoms of sweating, confusion, and agitation that have developed over the past hour. She has a history of schizophrenia, hay fever, and lower back pain and is currently taking sertraline, cetirizine, and olanzapine. The patient admits to occasional recreational use of cannabis and diazepam and also uses her partner’s tramadol. Upon examination, the patient has a temperature of 39.0ºC, a heart rate of 105 bpm, and a blood pressure of 143/75 mmHg. The doctor notes hyperreflexia, rigidity, bilateral mydriasis, and bilateral ankle clonus. What is the most likely cause of her presentation?