Review Question - QID 212833

A 27-year-old man presents to the emergency department with nausea and vomiting. The patient started experiencing these symptoms shortly after arriving home from going out to eat at a seafood restaurant. His symptoms progressed and now he reports having an odd metallic taste in his mouth, diffuse pruritus, and blurry vision. His temperature is 99.0°F (37.2°C), blood pressure is 120/72 mmHg, pulse is 50/min, respirations are 17/min, and oxygen saturation is 99% on room air. Physical exam reveals bradycardia and an inability of the patient to differentiate hot versus cold; no rash can be appreciated on exam. Which of the following is the most likely etiology of this patient’s symptoms?