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Endocrinology & Metabolic

Hypercalcaemia

Hypercalcaemia is a raised albumin-adjusted serum calcium, most often caused by primary hyperparathyroidism or malignancy; PTH is the pivotal fork, while severe or rapidly symptomatic hypercalcaemia is an emergency requiring careful rehydration and specialist treatment.

In a nutshell

Hypercalcaemia is most often primary hyperparathyroidism or malignancy. Repeat albumin-adjusted calcium and measure PTH: high/inappropriately normal PTH indicates PTH-dependent disease; suppressed PTH points to malignancy or another cause. Severe symptomatic disease needs saline rehydration, then specialist antiresorptive treatment and cause-directed management.

Classic presentation

An incidental mild calcium elevation with a non-suppressed PTH suggests primary hyperparathyroidism; a patient with cancer, dehydration, confusion and a rapid higher calcium rise suggests malignant hypercalcaemia.

Key points

  • PTH is the pivotal test and must be interpreted with the concurrent calcium.
  • Exclude FHH before sending a patient with primary hyperparathyroidism for surgery.
  • Adjusted calcium above 3.5 mmol/L or severe symptoms is an emergency; rehydrate carefully with saline.
  • NICE recommends parathyroid surgery for symptomatic/end-organ disease or adjusted calcium at least 2.85 mmol/L, and consideration even without those features.
  • Cinacalcet treats severe symptomatic hypercalcaemia when surgery is unsuitable; bisphosphonates are for fracture risk, not chronic primary-HPT hypercalcaemia.

First-line investigation

Repeat albumin-adjusted calcium with concurrent PTH, renal function and medication/supplement review.

Management

Recognise the emergency

  • Escalate severe/rapid hypercalcaemia, confusion, reduced consciousness, acute kidney injury, dehydration or arrhythmia for urgent hospital treatment.2

Rehydrate and investigate

  • Obtain ECG, adjusted calcium, PTH, renal function, phosphate and relevant cause-directed tests while restoring volume with carefully monitored saline.2,1

Control calcium

  • After rehydration, use specialist intravenous antiresorptive treatment when indicated, with BNF and renal-function checks.2,3

Assess end-organ disease

  • For primary hyperparathyroidism, assess renal function/stones, bone density, vitamin D and symptoms; investigate malignancy or other PTH-independent causes when PTH is suppressed.1,2

Treat the source

  • Refer for parathyroid surgery when indicated, or coordinate cancer, granulomatous, vitamin-D and specialist rescue treatment according to cause.1,2

Monitor recurrence and complications

  • Continue calcium, renal, bone and symptom monitoring, with post-parathyroidectomy review and specialist follow-up for persistent or recurrent disease.1,3

Exam traps

  • Do not use ionised calcium routinely for the NICE primary-HPT diagnostic pathway.
  • A normal-range PTH is inappropriate when calcium is high and can still indicate PTH-dependent disease.
  • FHH is a key mimic and generally does not benefit from parathyroidectomy.
  • Bisphosphonates lower calcium acutely but are not chronic treatment for primary-HPT hypercalcaemia.
  • Loop diuretics are not routine calcium-lowering therapy and can worsen volume depletion.

Illustrations

Brown tumour of hyperparathyroidism on histologyH&E section of a brown tumour showing haemorrhage, fibroblastic stroma and multinucleated giant cells, a skeletal consequence of prolonged PTH-driven bone resorption that may accompany hypercalcaemia.Nephron, Wikimedia Commons · CC-BY-SA-3.0

Key sources

  1. NICE NG132: Hyperparathyroidism (primary): diagnosis, assessment and initial management (Current NICE recommendations on repeat albumin-adjusted calcium, concurrent PTH, vitamin D, FHH exclusion, organ assessment, surgical referral, cinacalcet, bisphosphonates and monitoring; published 23 May 2019 and accessed 4 August 2026.)Updated 23 May 2019
  2. Society for Endocrinology: emergency management of acute hypercalcaemia in adults (UK endocrine emergency guidance covering severity, ECG, PTH-based assessment, saline rehydration, bisphosphonates, glucocorticoids, specialist rescue measures and dialysis; published 2016 and accessed 4 August 2026.)Updated 5 Oct 2016
  3. British National Formulary (BNF) (Current UK prescribing information for bisphosphonates, cinacalcet, calcitonin, denosumab, glucocorticoids and fluids; product-specific renal, dose and monitoring details must be checked at the point of care; accessed 4 August 2026.)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.