In this week’s Case Record of the Massachusetts General Hospital is a 4-year-old boy was admitted because of a 1-week history of back pain, with sleepiness, constipation, and refusal to walk. The serum calcium level was elevated. Initial radiographs and MRI studies were interpreted as normal. Diagnostic tests were performed.
In contrast to adults with malignant tumors, approximately 20 to 30% of whom have hypercalcemia, only 0.4 to 0.7% of pediatric cancer patients present with hypercalcemia.
• What are the symptoms of hypercalcemia?
Symptoms of hypercalcemia are dependent on both the serum level of calcium and the rate of rise. With mild hypercalcemia (<12 mg per deciliter [3 mmol per liter]), patients are usually asymptomatic. With moderately elevated calcium levels (12.0 to 13.5 mg per deciliter [3.0 to 3.4 mmol per liter]), weakness, anorexia, constipation, polyuria and polydipsia due to intravascular volume contraction usually develop. Severe hypercalcemia (>13.5 mg per deciliter) can manifest as a life-threatening metabolic emergency with cardiac and central nervous system effects including encephalopathy, seizure, and coma.
• What biochemical evaluation is recommended for children with hypercalcemia?
The underlying process can often be identified with the use of a focused biochemical evaluation that includes studies of urinary calcium excretion and serum levels of intact parathyroid hormone (PTH), phosphate, vitamin D, and PTH-related protein (PTHrP).
Figure 1. Calcium Homeostasis and Selected Causes of Hypercalcemia in Pediatric Patients.
Morning Report Questions
Q: How should hypercalcemia be managed in children?
A: Vigorous hydration with normal saline is indicated to manage hypercalcemia as it replenishes intravascular volume, dilutes the serum calcium, and enhances renal calcium excretion. If calcium levels remain elevated after volume repletion, administering furosemide to enhance calciuresis is recommended. Although calcitonin and a bisphosphonate have been used in recalcitrant cases, experience with the use of bisphosphonates such as pamidronate or zolendronate in children is limited and raises concern about side effects, so these are not generally recommended.
Q: What types of malignancies are associated with hypercalcemia in children?
A: Hypercalcemia occurs in association with rhabdomyosarcoma, hepatoblastoma, some brain tumors, neuroblastoma, and hematologic cancers, including lymphoma and acute leukemia.