Hypercalcemia Crisis Medical Slides

Present the time-based sequence: IMMEDIATE (hours 0-4) — aggressive IV NS 200-500 mL/hr (patients are profoundly volume-depleted from hypercalcemia-induced nephrogenic DI; may need 4-6 L in first 24 hours). Calcitonin 4 IU/kg IM/SC every 12 hours (onset 4-6 hours, reduces calcium 1-2 mg/dL, but tachyphylaxis by 48 hours). INTERMEDIATE (hours 0-24) — zoledronic acid 4 mg IV over 15 min (onset 2-4 days, peak effect 4-7 days, duration 2-4 weeks) OR pamidronate 60-90 mg IV over 2-4 hours. Do NOT use loop diuretics routinely — only after volume repletion and only if volume overload develops. Monitor calcium, electrolytes, and renal function every 6-12 hours.

Present the PTH-based algorithm: Check intact PTH (first branch point). PTH elevated/inappropriately normal → primary hyperparathyroidism (most common outpatient cause), familial hypocalciuric hypercalcemia (check calcium-creatinine clearance ratio <0.01), lithium-induced, tertiary hyperparathyroidism. PTH suppressed (<20 pg/mL) → check PTHrP, 1,25-dihydroxy vitamin D, 25-hydroxy vitamin D, SPEP/UPEP. PTHrP elevated → humoral hypercalcemia of malignancy (lung, renal, breast common). 1,25(OH)2D elevated → granulomatous disease (sarcoidosis) or lymphoma. 25(OH)D elevated → vitamin D intoxication. Normal PTHrP and vitamin D with malignancy → osteolytic metastases (breast, myeloma, lung).

Present options for bisphosphonate-refractory hypercalcemia: Denosumab 120 mg SC — RANKL inhibitor, effective when bisphosphonates fail (especially in renal impairment where bisphosphonates are contraindicated or less effective). Onset 2-4 days. Risk of severe rebound hypercalcemia when discontinued. Hemodialysis — use low-calcium or calcium-free dialysate for immediately life-threatening hypercalcemia (calcium >18 mg/dL, arrhythmias, severe AKI). Reduces calcium rapidly but transiently. Cinacalcet 30-90 mg PO BID — calcimimetic, useful for parathyroid carcinoma-related hypercalcemia. Gallium nitrate and plicamycin are historical agents largely replaced by newer therapies.