You are called to treat a 74-year-old with a severe bout of…

You are called to treat a 74-year-old with a severe bout of diarrhea and vomiting. It began this morning after the patient took their daily aspirin. The patient is now pale, cool, clammy, tachycardic, tachypnic, and responsive to verbal stimuli. Which of the following should you MOST likely suspect?