HemeOnc

Hypercalcemia of Malignancy

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Hypercalcemia of Malignancy, Malignant Hypercalcemia, Humoral Hypercalcemia of Malignancy

  • Epidemiology
  1. Incidence: 10-30% of cancer patients
  • Mechanisms
  1. Paraneoplastic syndromes (nearly all cases)
    1. Tumor secretes Parathyroid Hormone related peptide or PTHrP (80% of all cases)
      1. Present in Squamous Cell Carcinoma and Lymphoma
      2. Results in increased calcium reabsorption in Kidney
    2. Osteoclast-Activating factor production (20% of all cases)
      1. Present in Multiple Myeloma and metastases
      2. Results in osteolysis
    3. Endogenous Calcitriol (Vitamin D, 1,25-dihydroxyvitamin D, <1% of all cases)
      1. Present in Lymphomas
      2. Calcitriol acts as a bone-resorbing Cytokine
  2. Other rare mechanisms
    1. Immobilization
    2. Medications
    3. Parathyroid carcinoma
  • Symptoms
  1. See Hypercalcemia
  2. Altered Level of Consciousness, confusion to coma
  3. Gastrointestinal Symptoms
    1. Nausea or Vomiting
    2. Constipation
    3. Anorexia
  4. Dehydration
    1. Acute Kidney Injury
    2. Generalized weakness
    3. Excessive Thirst and polydipsia
    4. Decreased Urine Output
  • Labs
  1. Serum Electrolytes
  2. Serum Calcium
    1. Adjust for albumin, as Malnutrition is common (obtain Ionized Calcium if available)
    2. Mild Hypercalcemia: 10.5 to 11.9 mg/dl
    3. Moderate Hypercalcemia: 12.0 to 13.9 mg/dl
    4. Severe Hypercalcemia: >14 mg/dl
  • Management
  1. See Hypercalcemia for other management
  2. Consult Oncology, Endocrinology, Nephrology
  3. Acute Management
    1. Intravenous Fluids as Initial Management ( emergency department)
      1. Aggressive rehydration alone normalizes Serum Calcium in 30% of cases even within 12 hours
      2. Start 200 to 500 ml/hour with goal Urine Output 100-150 ml/hour
      3. Requires up to 4 liters Lactated Ringers or Normal Saline per 24 hours
  4. Monitor serum electrolytes
    1. Serum Calcium (may start as high as 14 mg/dl)
  5. Hypophosphatemia specific management
    1. Indication for Phosphorus Replacement: Serum Phosphate <3 mg/dl
    2. Neutro-Phos 250 mg Phosphorous PO or NG daily
  6. Hypercalcemia specific management
    1. Indications
      1. Serum Calcium >14 mg/dl if asymptomatic
      2. Serum Calcium >12 mg/dl if symptomatic
    2. Methods
      1. Glucocorticoids
        1. Indicated calcitriol overproduction as mechanism for Hypercalcemia
        2. Decrease intestinal calcium absorption
      2. Calcitonin
        1. Calcitonin 4 IU/kg IM or SQ
        2. Inhibits Osteoclasts (but diminishing returns after first dose due to tachyphylaxis)
      3. Bisphosphonates
        1. Inhibit Osteoclast mediated bone resorption (delayed effect over 1-3 days)
        2. Zoledronic acid: 4 mg IV over 15 min (preferred over Pamidronate)
        3. Pamidronate (Aredia) 60-90 mg IV given over 2 hours q4 hours
        4. Major (2001) J Clin Oncol 19:558-67 [PubMed]
      4. Monoclonal antibodies
        1. Denosumab (inhibits Osteoclasts)
  7. Other measures
    1. Hemodialysis Indications
      1. Refractory Acute Kidney Injury (GFR <20)
      2. Total Serum Calcium >18 mg/dl
      3. Congestive Heart Failure
      4. Neurologic Deficits
    2. Loop Diuretics (e.g. Furosemide)
      1. Indicated in Renal Failure or Congestive Heart Failure
      2. Furosemide 10-20 mg IV q6-12 hours after initial rehydration
  • Prognosis
  1. Hypercalcemia of Malignancy is a poor cancer prognostic sign
  2. Associated with >50% mortality in 30 days
  • References