What initial management step is appropriate for a patient with muscle weakness and hyperkalemia?

In the context of muscle weakness and hyperkalemia, administering IV calcium gluconate is the appropriate initial management step. Hyperkalemia poses a significant risk of cardiac complications, and calcium gluconate acts quickly to stabilize the cardiac membrane and protect the heart from the potentially harmful effects of elevated potassium levels. Calcium helps to counteract the increased myocardial excitability and reduces the likelihood of arrhythmias caused by hyperkalemia.

The other options, while they may be part of a broader management strategy for hyperkalemia, do not address the immediate need to protect the heart. Administering insulin and glucose can help drive potassium back into cells and lower serum potassium levels, but it does not offer immediate cardiac protection. Sodium polystyrene sulfate is generally used for chronic management of hyperkalemia by promoting potassium excretion, but it takes time to act and is not suitable for acute stabilization. Administering IV sodium is not a standard treatment for hyperkalemia and can lead to further complications. Therefore, the prompt administration of IV calcium gluconate is the best approach to protect the heart in the face of hyperkalemia and muscle weakness.