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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Hypercalcaemia: assessment and emergency treatment

Endocrinology and metabolism · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Severe hypercalcaemia causes renal, neurological and cardiac failure

Confusion, coma, profound dehydration, acute kidney injury, vomiting, severe weakness or arrhythmia with markedly raised calcium requires same-day hospital treatment. Society guidance regards adjusted calcium above 3.5 mmol/L as requiring urgent correction because of dysrhythmia and coma risk; symptoms and rate of rise also determine urgency below that level.

Action: Use ABCDE, ECG and monitored venous access, confirm calcium without delaying care, stop avoidable calcium-raising inputs and restore intravascular volume with intravenous 0.9% sodium chloride adapted to cardiac and renal status. Send PTH early, involve endocrinology and the likely definitive specialty, and select antiresorptive or cause-specific therapy after renal review.

Synopsis

Confirm and classify hypercalcaemia, recognise organ-threatening severity, restore volume safely and direct definitive care through the PTH response.

  • Verify an unexpected total calcium using albumin adjustment or ionised calcium when protein or acid-base disturbance makes total calcium unreliable.
  • The first mechanistic branch is PTH: hypercalcaemia should suppress it, so a high or inappropriately normal PTH indicates PTH-dependent disease.
  • Primary hyperparathyroidism and malignancy cause most clinically important hypercalcaemia, but medicines, granulomatous disease, thyrotoxicosis, immobility and vitamin excess matter.
  • PTH-independent hypercalcaemia with weight loss, bone pain, anaemia, kidney impairment or a known cancer requires an urgent malignancy-focused pathway.
  • Volume depletion both results from hypercalcaemia and reduces renal calcium excretion; careful isotonic saline is the foundation of acute treatment.
  • Loop diuretics do not routinely lower calcium and should be reserved for fluid overload after adequate volume replacement, not used to create forced diuresis.
  • Intravenous bisphosphonates act over days and require renal and cause review; calcitonin has a rapid but temporary role through specialist acute protocols.
  • Do not use bisphosphonates merely to chronically lower calcium in primary hyperparathyroidism; definitive parathyroid surgery and fracture treatment are separate decisions.

Investigation priorities

01
Repeat albumin-adjusted or ionised calciumFirst step

Confirm true hypercalcaemia and establish severity when albumin or critical illness affects total calcium.

Management branches

ResuscitateCorrect severe physiology

Marked calcium elevation accompanies symptoms, dehydration, renal injury or ECG concern.

  1. Assess ABCDE, ECG, fluid balance and cardiac-renal comorbidity, repeat calcium and obtain PTH and renal bloods without postponing treatment.
  2. Give monitored intravenous 0.9% sodium chloride to restore euvolaemia, adjusting rate to response and seeking renal or critical-care help when fluid tolerance is limited.
  3. If severe hypercalcaemia persists, choose an antiresorptive or rapid bridging treatment with specialist input, renal safeguards and planned serial calcium review.
LocaliseUse the PTH branch

Confirmed hypercalcaemia is stable enough for mechanistic investigation.

  1. Review medicines, supplements, previous calcium, kidney stones, fracture, cancer symptoms and family history and interpret simultaneous calcium and PTH.
  2. For non-suppressed PTH, assess vitamin D, renal function and urinary calcium before parathyroid referral; for suppressed PTH, pursue malignancy and vitamin D-mediated causes proportionately.
  3. Avoid localisation scans until biochemical primary hyperparathyroidism is established, because imaging plans surgery rather than making the diagnosis.

Key medicines

Intravenous 0.9% sodium chlorideUse the Society for Endocrinology and local resuscitation regimen, titrating the initial and ongoing rate to blood pressure, urine output, sodium, renal function and cardiac reserve rather than prescribing a fixed volume for every adult.Pulmonary oedema can occur in older adults or cardiac and renal failure. Reassess frequently; loop diuretic is not routine calcium therapy and is used only for fluid overload after rehydration.
Intravenous bisphosphonateAfter adequate rehydration, select the antiresorptive for the cause and renal function. For adult tumour-induced hypercalcaemia with albumin-corrected calcium at least 3.0 mmol/L, the current zoledronic acid SmPC recommends a single 4 mg intravenous infusion over no less than 15 minutes; use the specific BNF, SmPC or specialist protocol for other causes or products.Check renal function, calcium and vitamin D context; acute-phase reactions, kidney injury and delayed hypocalcaemia occur. Obtain dental and jaw-risk advice when repeated cancer or bone courses are anticipated.
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Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • Society for Endocrinology acute hypercalcaemia guidanceDirect UK emergency guidance for severity assessment, saline rehydration, antiresorptive treatment and cause-specific escalation.
  • NICE NG132 primary hyperparathyroidismCalcium confirmation, PTH interpretation, referral and surveillance.
  • NICE NG12 suspected cancer findingsCurrent referral actions for hypercalcaemia with features suggesting myeloma or another malignancy.
  • NICE BNF calcium imbalanceMedicine classes and UK prescribing context for urgent calcium reduction.
  • Zoledronic acid tumour hypercalcaemia SmPCLicensed adult tumour-induced hypercalcaemia threshold, single 4-mg dose, minimum 15-minute infusion, hydration and renal cautions.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draft
Clinical stateAwaiting review
JurisdictionUnited Kingdom