Final answer:
The nurse should watch for the complication of a cholinergic crisis during Tensilon testing for a patient with myasthenia gravis, as it can exacerbate symptoms and require emergency intervention.
Step-by-step explanation:
The patient with myasthenia gravis is undergoing Tensilon testing, which introduces edrophonium into the body, a drug that temporarily increases the amount of acetylcholine at the neuromuscular junction. This increased acetylcholine can be used to differentiate between myasthenia gravis and a cholinergic crisis. The nurse should be particularly alert for the complication of a cholinergic crisis, which can occur with an exacerbation of the symptoms of myasthenia gravis, such as muscle weakness, due to an overdose of anticholinesterase medication. A cholinergic crisis presents with signs of excessive muscarinic stimulation, such as nausea, vomiting, diarrhea, sweating, bradycardia, and possibly crisis. Therefore, the correct complication to watch for during Tensilon testing in a myasthenia gravis patient is (C) Cholinergic crisis.