A nurse is caring for a client who has a suspected diagnosis of myasthenia gravis. The provider prescribes a Tensilon test. Which of the following findings indicates a positive test?

Rationale: A. Electrical charge in a muscle increases in intensity is incorrect because the Tensilon test does not directly affect the electrical activity of muscles. Electromyography (EMG) measures electrical activity, but the Tensilon test works chemically at the neuromuscular junction. B. Muscle strength shows no change is incorrect because a lack of improvement indicates a negative test result, suggesting that the client may not have myasthenia gravis or that the test was inconclusive. C. Muscle contractions become progressively stronger is correct because Tensilon (edrophonium chloride) is a short-acting acetylcholinesterase inhibitor. In myasthenia gravis, antibodies attack acetylcholine receptors at the neuromuscular junction, causing weakness. By temporarily inhibiting the breakdown of acetylcholine, Tensilon increases the amount of acetylcholine available, which enhances communication between nerves and muscles. A rapid improvement in muscle strength—often observed in facial, eyelid, or limb muscles—confirms a positive test, supporting the diagnosis of myasthenia gravis. The effect is usually seen within 30–60 seconds and lasts 4–5 minutes. D. A pill-rolling tremor appears is incorrect because this type of tremor is associated with Parkinson’s disease, not myasthenia gravis, and is unrelated to the Tensilon test.