Hypercalcaemia of malignancy

At a glance

• Hypercalcaemia complicates up to a fifth of cancers at some stage, though newer anticancer and bone-targeted treatments have made it less common. It is the commonest cause of hypercalcaemia in inpatients.
• PTH is suppressed. A normal or high PTH means a second diagnosis, usually primary hyperparathyroidism.
• Treat with IV saline, then zoledronic acid 4 mg; add calcitonin if severe, and steroids for calcitriol-driven causes.