The nurse is caring for a client in acute kidney injury (AKI). Which complication would most clearly warrant the administration of polystyrene sulfonate?

Choice A reason: Hypernatremia refers to elevated serum sodium levels. Sodium polystyrene sulfonate is a cation-exchange resin that actually exchanges sodium ions for potassium ions in the intestine. Administering this medication would potentially increase sodium levels further, which would be contraindicated in a patient already suffering from hypernatremia. Choice B reason: Hyperkalemia is a life-threatening complication of acute kidney injury due to the kidneys' inability to excrete excess potassium. Sodium polystyrene sulfonate works by binding potassium in the gastrointestinal tract in exchange for sodium, allowing the excess potassium to be excreted via the feces, thereby lowering serum potassium levels. Choice C reason: Hypercalcemia is an elevation in serum calcium. This medication is not indicated for calcium imbalances. In the context of renal failure, patients are more likely to experience hypocalcemia due to impaired vitamin D activation and hyperphosphatemia, rather than hypercalcemia, which usually involves different pharmacological interventions like bisphosphonates. Choice D reason: Hypomagnesemia is a low level of magnesium. Sodium polystyrene sulfonate is specifically designed to target potassium exchange. It does not provide a mechanism for increasing magnesium levels. Electrolyte replacement therapy, usually via magnesium sulfate, would be required to correct a magnesium deficiency in a clinical setting.