Hypercalcaemia (or Hypercalcemia) is an elevated calcium level in the blood. (Normal range: 9-10.5 mg/dL or 2.2-2.6 mmol/L). It can be an asymptomatic laboratory finding, but because an elevated calcium level is often indicative of other diseases, a diagnosis should be undertaken if it persists. It can be due to excessive skeletal calcium release, increased intestinal calcium absorption, or decreased renal calcium excretion.
hydration is needed because many patients are dehydrated due to vomiting or renal defects in concentrating urine.
increased salt intake also can increase body fluid volume as well as increasing urine sodium excretion, which further increases urinary calcium excretion (In other words, calcium and sodium (salt) are handled in a similar way by the kidney. Anything that causes increased sodium (salt) excretion by the kidney will, en passant, cause increased calcium excretion by the kidney)
after rehydration, a loop diuretic such as furosemide can be given to permit continued large volume intravenous salt and water replacement while minimizing the risk of blood volume overload and thence pulmonary edema. In addition, loop diuretics tend to depress renal calcium reabsorption thereby helping to lower blood calcium levels
can usually decrease serum calcium by 1-3 mg/dL within 24 h
caution must be taken to prevent potassium or magnesium depletion
Additional therapy: bisphosphonates and calcitonin
bisphosphonates are pyrophosphate analogues with high affinity for bone, especially areas of high bone-turnover.
they are taken up by osteoclasts and inhibit osteoclastic bone resorption
current available drugs include (in order of potency): (1st gen) etidronate, (2nd gen) tiludronate, IV pamidronate, alendronate, risedronate, and (3rd gen) zolendronate
all patients with cancer-associated hypercalcemia should receive treatment with bisphosphonates since the 'first line' therapy (above) cannot be continued indefinitely nor is it without risk. Further, even if the 'first line' therapy has been effective, it is a virtual certainty that the hypercalcemia will recur in the patient with hypercalcemia of malignancy. Use of bisphoponates in such circumstances, then, becomes both therapeutic and preventative