Hypercalcemia of malignancy

Mechanisms

• PTHrP secretion (humoral hypercalcemia)
  • Squamous cell carcinoma, renal carcinoma, bladder carcinoma, breast carcinoma, ovarian carcinoma, prostate carcinoma, colorectal carcinoma, Non-Hidgkin lymphoma, CML, leukemia, lymphoma
• Osteolytic metastases
  • Breat carcinoma, multiple myeloma, lymphoma, leukemia
• 1,25-dihydroxyvitamin D production
  • Lymphoma (most common), ovarian dysgerminoma
• Ectopic PTH secretion
  • Ovarian carcinoma, lung carcinoma, neuroextodermal, thyroid papillary carcinoma, rhabdomyosarcoma, pancreatic carcinoma

Clinical Presentation

• Signs and symptoms of hypercalcemia (bones, moans, groans, overtones)
• Volume depleted
• Altered mental status
• Constipation

Management

• Indications for treatment:
  • Calcium >3.5 is dangerous!
  • Symptoms of hypercalcemia, especially if in the 3 to 3.5 range
• IV fluids 200 to 300 mL/h initially
• Salmon calcitonin 4 u/kg
  • Continue every 6 to 12 hours if calcium responds
• Zoledronic acid 4mg IV over 15 minutes or pamidronate 60 to 90 mg IV over 2 hours