Phys · endocrine
Calcium and Bone Disorders
Also known as hypercalcaemia · primary hyperparathyroidism · secondary hyperparathyroidism · tertiary hyperparathyroidism · hypercalcaemia of malignancy · PTHrP-mediated hypercalcaemia · humoral hypercalcaemia of malignancy · hypocalcaemia · hypoparathyroidism · post-surgical hypoparathyroidism · autoimmune hypoparathyroidism · pseudohypoparathyroidism · DiGeorge syndrome · 22q11.2 deletion syndrome · osteoporosis · DEXA scan · T-score · FRAX · bisphosphonate · alendronate · zoledronic acid · denosumab · teriparatide · raloxifene · drug holiday · osteomalacia · Looser zones · rickets · cinacalcet · calcitonin
Consultant-physician-depth guide to calcium homeostasis and bone disorders — hypercalcaemia (primary hyperparathyroidism, malignancy-associated, granulomatous, drug-induced), hypocalcaemia (post-surgical hypoparathyroidism, autoimmune, vitamin D deficiency, CKD, hypomagnesaemia), osteoporosis (DEXA, FRAX, bisphosphonates, denosumab, teriparatide, anabolic therapy, drug holidays), and osteomalacia (vitamin D deficiency, Looser zones) — structured for FRACP DWE and DCE preparation.
Checked against its sources on 3 Sept 2026
On this page
Study tools
Your progress
Saved on this device.
Practise this topic
Target exams
Red flags
- Severe hypercalcaemia (corrected calcium above 3.5 mmol/L) with altered mental state or AKI — medical emergency requiring IV saline and bisphosphonate
- Symptomatic hypocalcaemia — perioral tingling, carpopedal spasm, Trousseau or Chvostek sign, prolonged QT on ECG — give IV calcium gluconate
- Post-thyroidectomy or post-parathyroidectomy hypocalcaemia — the commonest acute cause of hypocalcaemia; check calcium within 6 to 12 hours
- Hypocalcaemia with hypomagnesaemia — functional hypoparathyroidism; PTH will not correct until magnesium is repleted
- Osteoporotic fragility fracture (hip, vertebra, distal forearm) — high mortality and re-fracture risk; must initiate bone protection within weeks
- Atypical femoral fracture on bisphosphonate — prodromal thigh pain, transverse fracture pattern; stop the bisphosphonate and refer urgently
- Osteonecrosis of the jaw on bisphosphonate or denosumab — exposed necrotic mandibular or maxillary bone; refer to maxillofacial
Calcium and Bone Disorders
The answer first
Calcium disorders are high-yield because they are common, treatable, and test your ability to interpret an integrated hormone axis. The single most important initial step in any hypercalcaemic patient is to measure intact PTH simultaneously with the corrected calcium — this one test splits all hypercalcaemia into PTH-dependent (primary hyperparathyroidism) and PTH-independent (malignancy, granulomatous, vitamin D intoxication) causes.[1]
The framework is the calcium-PTH-vitamin D axis. PTH raises calcium by mobilising bone, increasing renal calcium reabsorption, and stimulating renal 1-alpha-hydroxylase to activate vitamin D. Severe symptomatic hypercalcaemia demands IV saline first, then an antiresorptive. Osteoporosis is defined by DEXA T-score below negative 2.5 and treated with an antiresorptive first.[1][6]
References8ShowHide
- [1]Bilezikian JP, Khan AA, Silverberg SJ, et al. Evaluation and Management of Primary Hyperparathyroidism: Summary Statement and Guidelines from the Fifth International Workshop J Bone Miner Res, 2022.PMID 36245251
- [2]Bilezikian JP, Brandi ML, Eastell R, et al. Guidelines for the management of asymptomatic primary hyperparathyroidism: summary statement from the Fourth International Workshop J Clin Endocrinol Metab, 2014.PMID 25162665
- [3]El-Hajj Fuleihan G, Clines GA, Hu MI, et al. Treatment of Hypercalcemia of Malignancy in Adults: An Endocrine Society Clinical Practice Guideline J Clin Endocrinol Metab, 2023.PMID 36545746
- [4]Walsh J, Gittoes N, Selby P SOCIETY FOR ENDOCRINOLOGY ENDOCRINE EMERGENCY GUIDANCE: Emergency management of acute hypercalcaemia in adult patients Endocr Connect, 2016.PMID 27935816
- [5]Brandi ML, Bilezikian JP, Shoback D, et al. Management of Hypoparathyroidism: Summary Statement and Guidelines J Clin Endocrinol Metab, 2016.PMID 26943719
- [6]Camacho PM, Petak SM, Binkley N, et al. AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS/AMERICAN COLLEGE OF ENDOCRINOLOGY CLINICAL PRACTICE GUIDELINES FOR THE DIAGNOSIS AND TREATMENT OF POSTMENOPAUSAL OSTEOPOROSIS-2020 UPDATE Endocr Pract, 2020.PMID 32427503
- [7]Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline J Clin Endocrinol Metab, 2011.PMID 21646368
- [8]Stewart AF Clinical practice. Hypercalcemia associated with cancer N Engl J Med, 2005.PMID 15673803