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Hypercalcemia of malignancy — ABIM Board MCQ

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ModerateEndocrinology/MetabolismHypercalcemia of malignancyABIM Board

A 68-year-old man with squamous cell lung cancer is evaluated for confusion and constipation. His serum calcium concentration is 14.2 mg/dL, creatinine is 1.1 mg/dL, and ECG shows a shortened QT interval. Examination demonstrates dry mucous membranes and orthostatic hypotension. Which of the following is the most appropriate initial treatment regimen?

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Correct answer: B — Intravenous 0.9% saline, subcutaneous calcitonin, and intravenous zoledronic acid

This patient has severe, symptomatic hypercalcemia of malignancy, indicated by calcium of 14.2 mg/dL, neuropsychiatric and gastrointestinal symptoms, shortened QT interval, and volume depletion. Initial treatment includes intravenous isotonic saline to restore renal perfusion and calcium excretion, calcitonin for a rapid but short-lived reduction in calcium, and an antiresorptive agent such as intravenous zoledronic acid for sustained control. Thiazides decrease urinary calcium excretion and can worsen hypercalcemia. Calcium, cholecalciferol, and calcitriol would also aggravate it. Glucocorticoids are principally useful for calcitriol-mediated hypercalcemia, such as in lymphoma. Fluid restriction worsens hypovolemia, and loop diuretics are not routinely used unless volume overload develops after adequate rehydration.

Reference: El-Hajj Fuleihan G, et al. Treatment of Hypercalcemia of Malignancy in Adults: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism. 2023;108:507-528. https://pubmed.ncbi.nlm.nih.gov/36545746/