In hypercalcemia of malignancy, what is the typical pathophysiology and initial management steps?

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Multiple Choice

In hypercalcemia of malignancy, what is the typical pathophysiology and initial management steps?

Hypercalcemia of malignancy typically results from tumor-driven bone resorption, most often due to PTH-related peptide (PTHrP) production by the cancer, which acts like PTH to increase calcium reabsorption in the kidneys and stimulate osteoclast-mediated bone breakdown. Local osteolytic metastases can also release calcium. PTH is usually suppressed in this setting, and vitamin D–mediated effects are less common except in certain lymphomas. Initial management aims to correct volume depletion and promote calcium excretion, then rapidly reduce bone resorption. Start with aggressive IV isotonic saline to restore intravascular volume and enhance calciuresis. After rehydration, give an antiresorptive agent to blunt ongoing bone resorption—bisphosphonates (such as zoledronic acid or pamidronate) are first-line, with denosumab as an alternative, especially if there is renal impairment or bisphosphonate failure. Calcitonin can be used for rapid, short-term lowering while waiting for the slower-onset bisphosphonates. Glucocorticoids may help in cases of vitamin D–mediated hypercalcemia or certain malignancies. Importantly, treat the underlying malignancy to prevent recurrence. The other options point to different causes of hypercalcemia or the opposite condition: primary hyperparathyroidism involves excess PTH, vitamin D intoxication raises calcium through excess vitamin D, and hypocalcemia with tetany is not hypercalcemia at all.

Hypercalcemia of malignancy typically results from tumor-driven bone resorption, most often due to PTH-related peptide (PTHrP) production by the cancer, which acts like PTH to increase calcium reabsorption in the kidneys and stimulate osteoclast-mediated bone breakdown. Local osteolytic metastases can also release calcium. PTH is usually suppressed in this setting, and vitamin D–mediated effects are less common except in certain lymphomas.

Initial management aims to correct volume depletion and promote calcium excretion, then rapidly reduce bone resorption. Start with aggressive IV isotonic saline to restore intravascular volume and enhance calciuresis. After rehydration, give an antiresorptive agent to blunt ongoing bone resorption—bisphosphonates (such as zoledronic acid or pamidronate) are first-line, with denosumab as an alternative, especially if there is renal impairment or bisphosphonate failure. Calcitonin can be used for rapid, short-term lowering while waiting for the slower-onset bisphosphonates. Glucocorticoids may help in cases of vitamin D–mediated hypercalcemia or certain malignancies. Importantly, treat the underlying malignancy to prevent recurrence.

The other options point to different causes of hypercalcemia or the opposite condition: primary hyperparathyroidism involves excess PTH, vitamin D intoxication raises calcium through excess vitamin D, and hypocalcemia with tetany is not hypercalcemia at all.

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