MSFinals-2201

MSFinals-2201

A 28-year-old man presents to the emergency department with difficulty swallowing and blurred vision. He is worried about his slurred speech which started the day before. He has no past medical history or current medications.

Upon examination, the patient appears disheveled and has multiple track marks on both arms with surrounding redness. His vital signs are normal. Cranial nerve examination reveals bilateral ptosis, diplopia, impaired pupil accommodation, and impaired gag reflex. The patient’s speech is also slurred. Upper limb examination shows hypotonia and 4/5 power bilaterally, while sensation is intact. Lower limb examination is unremarkable.

What is the most likely causative organism for this patient’s presentation?