Pamidronate therapy for hypercalcemia of childhood malignancy

Background Hypercalcemia is a common complication of adult malignancies, but uncommon in childhood cancers. The mechanism leading to hypercalcemia varies with the primary tumour and can include the following: 1) Increased osteoclastic activity at the site of the tumour in the bone marrow 2) A paraneoplastic phenomenon secondary to PTH-related peptide (PTHrP) secretion or 1,25–dihydroxyvitamin D by the tumour. Patients with serum calcium above 3.5 mmol/L tend to be symptomatic and require prompt treatment. The symptoms are generally non-specific and include lethargy, nausea, vomiting, constipation and abdominal pain. Left untreated, hypercalcemia can progress to stupor and coma.