Hypercalcaemia is found in about 1% of all hospitalised patients and is caused by malignancy in 46% of all cases and by pHPT in 35%. In the remaining 19%, other conditions are responsible. These include sarcoidosis, immobilisation and medications such as thiazides or active metabolites of vitamin D. Patients with mild hypercalcaemia have no symptoms. The term “hypercalcaemic syndrome” refers to a constellation of symptoms independent of the aetiology, including renal, gastrointestinal and neuropsychiatric changes.