Nokea
A 43-year-old woman with diagnosed myasthenia gravis presents with profound skeletal muscle weakness. We are unsure whether she is experiencing a cholinergic crisis or a myasthenic crisis, so we administer a usually appropriate dose of parenteral edrophonium. Assume the patient was actually experiencing a cholinergic crisis. Which of the following is the most likely response to the drug?
Correct Answer: D
Rationale: The correct answer is D: Ventilatory distress or failure. Edrophonium is a short-acting acetylcholinesterase inhibitor used to differentiate between myasthenic and cholinergic crises. In a cholinergic crisis, which is an excess of acetylcholine, administering edrophonium can worsen symptoms due to further acetylcholine accumulation. This can lead to excessive stimulation of the respiratory muscles, resulting in ventilatory distress or failure.
Choice A is incorrect because cholinergic crisis typically causes hypotension, not hypertension. Choice B is incorrect because edrophonium-induced tachycardia can worsen myocardial ischemia, not angina. Choice C is incorrect because increased ventricular automaticity would not be a common response to edrophonium in a cholinergic crisis.