The most common paraneoplastic syndrome, hypercalcemia occurs in about 10% of cancer pts, particularly those with lung, breast, head and neck, and kidney cancer and myeloma. Bone resorption mediated by parathyroid hormone-related protein is the most common mechanism; interleukin 1 (IL-1), IL-6, tumor necrosis factor, and transforming growth factor β may act locally in tumor-involved bone. Pts usually present with nonspecific symptoms: fatigue, anorexia, constipation, weakness. Hypoalbuminemia associated with malignancy may make symptoms worse for any given serum calcium level because more calcium will be free rather than protein bound.
Treatment: Hypercalcemia Saline hydration, antiresorptive agents (e.g., pamidronate, 60-90 mg IV over 4 h, or zoledronate, 4-8 mg IV), and glucocorticoids usually lower calcium levels significantly within 1-3 days. Treatment effects usually last several weeks. Treatment of the underlying malignancy is also important. |
Section 2. Medical Emergencies