Hypercalcaemia of MalignancyUrgent

Known myeloma, now confused and constipated — corrected Ca²⁺ 3.6. Volume first, calcitonin for speed, zoledronate for durability.

• Confusion, coma
• Corrected Ca²⁺ >3.5
• Short QT on ECG
• Oliguria

• Primary hyperparathyroidism (check PTH!)
• Vitamin D toxicity, granulomatous disease
• Thiazides, lithium, milk-alkali
• Myeloma vs PTHrP solid tumour

• Admit: Corrected Ca²⁺ ≥3.0 with symptoms, or ≥3.5 regardless
• Calcitonin: Immediately if severe/symptomatic
• Zoledronate: 4 mg IV — onset 2–4 d, duration weeks

• Calcitonin = hours, zoledronate = days, denosumab = renal-safe — layer them
• Correct for albumin or check ionised Ca²⁺ — hypoalbuminaemia hides true levels
• PTH suppressed + high Ca²⁺ in malignancy = PTHrP or osteolytic (myeloma)

• Give furosemide before volume repletion — worsens hypercalcaemia and prerenal AKI
• Give full-dose zoledronate blindly in severe CKD — denosumab 120 mg SC is safer
• Wait days for bisphosphonate in a symptomatic patient — calcitonin covers the gap

• Treating a number without correcting for albumin
• Fluids forgotten while waiting for zoledronate
• Hypophosphataemia ignored during repletion
• No malignancy treatment plan — Ca²⁺ will recur

Step down when Ca²⁺ <3.0 and stable on maintenance hydration; oncology for disease-modifying therapy; dental review before ongoing bisphosphonates (ONJ risk).