Final answer:
In a patient with myasthenia gravis and decreased serum magnesium levels, the most important nursing action is to monitor for increased muscle weakness and potential respiratory distress, as low magnesium can exacerbate the symptoms of MG.
Step-by-step explanation:
When managing a patient with myasthenia gravis (MG) who is undergoing immunosuppressive therapy, a decrease in serum magnesium levels can have significant implications for neuromuscular function. This is because magnesium plays a vital role in nerve transmission and muscle contraction. In patients with MG, low magnesium can exacerbate muscle weakness and compromise respiratory function. Therefore, the most important nursing action, in addition to contacting the healthcare provider, is to monitor the patient for signs of increased muscle weakness and potential respiratory distress. It is also critical to assess the patient's ability to swallow and their speech as MG can affect these functions.
Patients with myasthenia gravis are at risk for myasthenia crisis, a severe exacerbation of muscle weakness that can affect breathing. Hence, it is crucial for nurses to closely observe the patient's respiratory status and prepare for emergency intervention if necessary. Dietary adjustments or magnesium supplementation may be considered based on medical advice to address hypomagnesemia.