Hypercalcaemia in malignancy
Hypercalcaemia is a common, potentially life‑threatening metabolic complication of cancer (occurs in ~20-30% of patients). Emergency management aims to stabilise the patient, identify the mechanism and underlying malignancy where possible, and begin measures to lower calcium while arranging definitive oncology/haematology care.
Triage summary (ED priorities)
- Severity bands (practical ED guidance; Society for Endocrinology / RCEM):
- Mild: < 3.0 mmol/L - often asymptomatic; investigate.
- Moderate: 3.0-3.5 mmol/L - frequently symptomatic; treatment usually required.
- Severe:
> 3.5 mmol/L - high risk of arrhythmia, coma; urgent correction and specialist input.
- Immediate actions:
- ABCs and airway protection if reduced consciousness.
- Cardiac monitoring if severe hypercalcaemia or ECG changes.
- Establish IV access.
- Stop exogenous calcium and vitamin D supplements and contributory drugs (thiazides, lithium, calcitriol).
- Commence isotonic saline unless contraindicated; tailor to cardiac/renal comorbidity.
Physiology and mechanisms - concise
- Serum calcium exists as protein‑bound (≈40-50%, mainly albumin) and ionised (free) fractions; ionised calcium mediates clinical effects.
- Major regulators: parathyroid hormone (PTH), calcitriol (1,25‑OH2 vitamin D) and calcitonin.