A 64 year old man with multiple myeloma having a serum calcium of 3.2 mmol/l should receive which treatment as the next step?

In the context of a 64-year-old man with multiple myeloma and a serum calcium level of 3.2 mmol/L, the most appropriate treatment is intravenous fluids. This patient's hypercalcemia is likely related to the malignancy, and the initial management typically involves hydration and saline infusion. Administering IV fluids helps to increase the renal perfusion and promote calcium excretion, effectively helping to lower serum calcium levels.

By providing hydration, it can mitigate potential complications associated with hypercalcemia, such as acute kidney injury and the associated risks from too high serum calcium. In multiple myeloma, hypercalcemia is a common complication, and maintaining hydration is crucial.

While IV bisphosphonates are a common treatment for hypercalcemia associated with malignancies, they are typically considered after immediate rehydration has been established. IV calcium gluconate is used primarily to treat hypocalcemia or cardiac issues related to hyperkalemia and is not indicated in the treatment of hypercalcemia. IV insulin is not used in this context, as it is primarily reserved for the treatment of hyperglycemia in diabetic patients.

Thus, initiating treatment with IV fluids is the most logical next step in the management of hypercalcemia in this