A patient presents with excessive thirst, confusion, and muscle weakness. Upon assessment, their serum sodium level is found to be elevated. Which nursing intervention should be prioritized to address this patient's condition?

Hypernatremia is serum sodium >145 mmol/L causing cellular dehydration, increased plasma osmolality, neuronal shrinkage, and neurological dysfunction. Clinical manifestations include thirst, confusion, muscle weakness, and risk of seizures or coma due to intracellular fluid loss. Rationale: A. Administering a diuretic may increase water loss and worsen hypernatremia unless specifically indicated. It does not address the primary deficit of free water. This intervention can exacerbate fluid imbalance and further elevate sodium concentration. B. Seizure precautions may be necessary in severe cases, but they are not the first priority. The underlying issue is dehydration and hyperosmolarity. Management must focus on correcting water deficit rather than only preventing complications. C. Providing oral fluid intake directly addresses free water deficit and helps dilute elevated serum sodium levels. Gradual rehydration restores cellular balance and reduces neurological symptoms. This is the priority intervention for correcting hypernatremia safely. D. Isotonic saline contains sodium and may worsen hypernatremia if used inappropriately. It is indicated in hypovolemia but not for correcting elevated sodium levels alone. This does not effectively reduce serum sodium concentration.