Medication overdoses and toxicities Quiz: Ace Your Exams

A 60-year old man is brought to the emergency department for evaluation of new onset confusion. His partner reports he has been suffering from “hay fever” throughout the week, but today she noticed he was not acting like himself. His partner states, “I went to check on him today, and he did not know where he was; he is usually totally with it.” The patient has no other medical conditions and does not take any other medications. He does not smoke tobacco or use illicit drugs. Temperature is 38.8C (104.84F), respirations are 18/minute, pulse is 120/minute, and blood pressure is 140/90 mmHg. On physical examination, the patient appears agitated and disoriented; he is oriented to person only. The patient’s skin is dry and flushed, the pupils are mydriatic and poorly reactive to light, and bowel sounds are decreased. Which of the following best describes the underlying mechanism responsible for this patient’s clinical condition?