Hypercalcaemia and primary hyperparathyroidism

Hypercalcaemia is common. Around 90% of cases are caused by one of two conditions: primary hyperparathyroidism (PHPT), the most common cause in outpatient settings and typically detected incidentally on blood tests; or malignancy, usually already overt and the most common cause in hospital inpatients. Clinical context and key investigations, particularly serum parathyroid hormone, lead to the cause. For hypercalcaemia of malignancy needing treatment, guidelines recommend intravenous bisphosphonate or denosumab initially, with calcitonin added if necessary. The latest management guidelines for PHPT are from the 5th International Workshop on the Evaluation and Management of Primary Hyperparathyroidism (2022) and the UK National Institute for Health and Care Excellence (2019). Long-term effects of monitored and untreated PHPT are increasingly recognized so parathyroid surgery is increasingly used outside its specific indications in individuals aged 50–70 years. There are updated guidelines on screening for genetic causes of PHPT before parathyroid surgery, as this can influence the type of surgery. Unsuccessful primary parathyroidectomy (5–10%) should be managed by a specialist multidisciplinary team.