Initial rehydration

Acute severe hypercalcaemia (serum total calcium concentration corrected for albumin above 3.0 mmol/L) often causes dehydration and electrolyte depletion, leading to a deterioration in kidney function that increases the serum calcium concentration further. Rehydration with a sodium chloride infusion is essential; it can be expected to reduce the serum calcium concentration, but not necessarily to normalise it. A reasonable infusion rate for an adult is:

Rehydration in a child is determined by weight and degree of dehydration.

Monitor cardiac function until serum calcium is reduced to a safe concentration (ie within or slightly above the normal range). Hypercalcaemia increases the risk of cardiac complications, particularly in older people and patients with a history of cardiac disease.

Intravenous furosemide (frusemide) can be used under specialist supervision to treat fluid overload following rehydration. Do not use furosemide for primary treatment of hypercalcaemia because it can deplete intravascular volume further.