II. Epidemiology
- Incidence: 10-30% of cancer patients
III. Mechanisms
- Paraneoplastic syndromes (nearly all cases)
- Tumor secretes Parathyroid Hormone related peptide or PTHrP (80% of all cases)
- Present in Squamous Cell Carcinoma and Lymphoma
- Results in increased Calcium reabsorption in Kidney
- Osteoclast-Activating factor production (20% of all cases)
- Present in Multiple Myeloma and metastases
- Results in osteolysis
- Endogenous Calcitriol (Vitamin D, 1,25-dihydroxyvitamin D, <1% of all cases)
- Tumor secretes Parathyroid Hormone related peptide or PTHrP (80% of all cases)
- Other rare mechanisms
- Immobilization
- Medications
- Parathyroid carcinoma
IV. Causes: Primarily Breast, lung and Bone Cancers
- Most common causes
- Other causes
- Squamous Cell Carcinoma of head and neck
- Kidney Cancer
- Cervical Cancer
V. Symptoms
- See Hypercalcemia
- Altered Level of Consciousness, confusion to coma
- Gastrointestinal Symptoms
-
Dehydration
- Acute Kidney Injury
- Generalized weakness
- Excessive Thirst and polydipsia
- Decreased Urine Output
VI. Labs
- Serum Electrolytes
-
Serum Calcium
- Adjust for albumin, as Malnutrition is common (obtain Ionized Calcium if available)
- Mild Hypercalcemia: 10.5 to 11.9 mg/dl
- Moderate Hypercalcemia: 12.0 to 13.9 mg/dl
- Severe Hypercalcemia: >14 mg/dl
VII. Diagnostics
VIII. Management
- See Hypercalcemia for other management
- Consult Oncology, Endocrinology, Nephrology
- Acute Management
- Intravenous Fluids as Initial Management ( emergency department)
- Aggressive rehydration alone normalizes Serum Calcium in 30% of cases even within 12 hours
- Start 200 to 500 ml/hour with goal Urine Output 100-150 ml/hour
- Requires up to 4 liters Lactated Ringers or Normal Saline per 24 hours
- Intravenous Fluids as Initial Management ( emergency department)
- Monitor serum Electrolytes
- Serum Calcium (may start as high as 14 mg/dl)
-
Hypophosphatemia specific management
- Indication for Phosphorus Replacement: Serum Phosphate <3 mg/dl
- Neutro-Phos 250 mg Phosphorous PO or NG daily
-
Hypercalcemia specific management
- Indications
- Serum Calcium >14 mg/dl if asymptomatic
- Serum Calcium >12 mg/dl if symptomatic
- Methods
- Glucocorticoids
- Indicated calcitriol overproduction as mechanism for Hypercalcemia
- Decrease intestinal Calcium absorption
- Calcitonin
- Calcitonin 4 IU/kg IM or SQ
- Inhibits Osteoclasts (but diminishing returns after first dose due to tachyphylaxis)
- Bisphosphonates
- Inhibit Osteoclast mediated bone resorption (delayed effect over 1-3 days)
- Zoledronic acid: 4 mg IV over 15 min (preferred over Pamidronate)
- Pamidronate (Aredia) 60-90 mg IV given over 2 hours q4 hours
- Major (2001) J Clin Oncol 19:558-67 [PubMed]
- Monoclonal antibodies
- Denosumab (inhibits Osteoclasts)
- Glucocorticoids
- Indications
- Other measures
- Hemodialysis Indications
- Refractory Acute Kidney Injury (GFR <20)
- Total Serum Calcium >18 mg/dl
- Congestive Heart Failure
- Neurologic Deficits
- Loop Diuretics (e.g. Furosemide)
- Indicated in Renal Failure or Congestive Heart Failure
- Furosemide 10-20 mg IV q6-12 hours after initial rehydration
- Hemodialysis Indications
IX. Prognosis
- Hypercalcemia of Malignancy is a poor cancer prognostic sign
- Associated with >50% mortality in 30 days
X. References
- Aurora and Herbert in Majoewsky (2013) EM:Rap 13(10): 1-4
- Long, Long and Koyfman (2020) Crit Dec Emerg Med 34(11): 17-24
- Higdon (2006) Am Fam Physician 74:1873-80 [PubMed]
- Higdon (2018) Am Fam Physician 97(11):741-8 [PubMed]
- Stewart (2005) N Engl J Med 352:373-9 [PubMed]
- Zuckerman (2012) Blood 120(10): 1993-2002 [PubMed]