VOLUME FIRST:0.9% saline 200–300 mL/h targeting urine output 100–150 mL/h — restores GFR and calciuresis; furosemide ONLY after fully volume-repleted if overloaded
Calcitonin — the fast arm:4 IU/kg SC/IM q12h — onset 2–4 h, drops Ca²⁺ ~0.5 mmol/L; tachyphylaxis after 48 h (bridge only)
Bisphosphonate — the durable arm:zoledronic acid 4 mg IV over 15 min (onset 2–4 days, lasts weeks; renal dose-adjust); severe CKD → denosumab 120 mg SC instead
Special cases:calcitriol-driven (lymphoma/granuloma) → prednisolone 40–60 mg; refractory + CKD/HF → haemodialysis with low-calcium bath
Fix the cause:PTHrP/myeloma workup; disease control (chemo, SCT, radiotherapy) is the only lasting cure; avoid thiazides, lithium, Ca²⁺/vitamin D supplements
Calculators:
Order set
Corrected Ca²⁺, phosphate, Mg²⁺, PTH, creatinine
0.9% saline 200–300 mL/h
Calcitonin 4 IU/kg SC q12h
Zoledronic acid 4 mg IV (or denosumab 120 mg SC if CKD)
ECG — QT shortens
Strict fluid balance + urine output
Monitor
q12–24 hCorrected Ca²⁺ until <3.0 and falling
HourlyUrine output — target 100–150 mL/h
DailyCreatinine, phosphate, Mg²⁺; confusion score
Day 2–4Bisphosphonate effect lands — wean fluids as Ca²⁺ falls
Escalate / ICU
Corrected Ca²⁺ >3.5 or severe symptoms at any level
Correct for albumin or check ionised Ca²⁺ — hypoalbuminaemia hides true levels
PTH suppressed + high Ca²⁺ in malignancy = PTHrP or osteolytic (myeloma)
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
Confusion, coma
Corrected Ca²⁺ >3.5
Short QT on ECG
Oliguria
Differentials
Primary hyperparathyroidism (check PTH!)
Vitamin D toxicity, granulomatous disease
Thiazides, lithium, milk-alkali
Myeloma vs PTHrP solid tumour
Common mistakes
Treating a number without correcting for albumin
Fluids forgotten while waiting for zoledronate
Hypophosphataemia ignored during repletion
No malignancy treatment plan — Ca²⁺ will recur
Disposition & follow-up
Step down when Ca²⁺ <3.0 and stable on maintenance hydration; oncology for disease-modifying therapy; dental review before ongoing bisphosphonates (ONJ risk).
💊 Treatment detail — doses & preparation
0.9% Sodium chloridecrystalloid
DoseBolus 500 mL over 15–30 min, reassess; maintenance 1–1.5 mL/kg/h
Preparation500/1000 mL bags; add KCl only after urine output confirmed
MonitorHyperchloraemic acidosis with large volumes — prefer balanced (LR) for resuscitation
Calcitoninhypocalcaemic agent
Dose4 IU/kg SC/IM q12h (hypercalcaemia) — onset 2–4 h
Preparation100 IU/mL ampoule SC/IM
MonitorCa²⁺ q12 h; tachyphylaxis after 48 h — bridge to bisphosphonate
Zoledronic acidIV bisphosphonate
Dose4 mg IV over ≥15 min (hypercalcaemia, myeloma bone); renal dose-adjust (3–3.5 mg if CrCl 30–60)
Preparation4 mg/5 mL ready solution or vial dilute in 100 mL NS
ICU Decoded — original critical-care and internal-medicine pathways by
Dr Javed Akhtar, each cited to a current guideline. For education and quick
reference; verify every dose against local protocols before prescribing.