Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Edrophonium chloride (Tensilon) acts by which mechanism for diagnosing myasthenia gravis?

1. Inhibiting acetylcholine release

2. Blocking voltage-gated calcium channels

3. Inhibiting acetylcholinesterase

4. Stimulating sympathetic nervous system

The correct answer is: Inhibiting acetylcholinesterase

Edrophonium chloride, commonly known as Tensilon, is used in the diagnosis of myasthenia gravis due to its mechanism of action as an acetylcholinesterase inhibitor. By inhibiting acetylcholinesterase, edrophonium effectively increases the concentration of acetylcholine at the neuromuscular junction. This can temporarily enhance communication between nerve endings and muscle fibers, leading to improved muscle strength in patients with myasthenia gravis, who have a deficiency in acetylcholine receptors. The increase in acetylcholine allows for a better assessment of the patient's symptoms, as improvement in muscle strength following administration of edrophonium is a characteristic response in individuals with this condition. This test is particularly useful in confirming a diagnosis after clinical symptoms and other diagnostic tests suggest myasthenia gravis.