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Key Clinical Questions
What is the initial management of tumor-related emergencies?
What is the initial management of cancer treatment related emergencies?
Which oncologic emergencies require an intensive care setting and which can be managed on a hospitalist service? What are the indications for emergent consultation with other specialists?
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Patients with cancer are at risk for potentially life-threatening medical complications. The possibility of rapid decompensation in cancer patients requires preventive strategies, prompt recognition, and treatment when complications occur. Emergent conditions encountered in the inpatient setting may be due to the presence of cancer itself or may be the result of anticancer therapy. They may be structural or metabolic in etiology.
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TUMOR-RELATED EMERGENCIES
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Elevation of the total serum calcium may be associated with drugs, malignancy, hyperparathyroidism, and other diseases (such as sarcoidosis, tuberculosis, and endocrine disorders). Total calcium reflects the free or ionized calcium (the biologically active form of calcium), calcium bound to organic and inorganic anions, and that bound to albumin. When protein concentrations, especially albumin, are abnormal, total calcium levels change in the same direction whereas ionized calcium remains relatively constant due to hormonal control. The biologically active calcium level can be estimated by calculating the corrected calcium for the serum albumin level or by measuring serum ionized calcium concentration (see Chapter 240 [Disorders of Calcium and Phosphorous]).
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PRACTICE POINT
Volume replacement with isotonic saline is the first line of therapy for symptomatic hypercalcemia.
A single elevated serum calcium concentration should be repeated to confirm the diagnosis.
Corrected calcium = Serum calcium (mg/dL) + 0.8*(normal albumin level – patient’s albumin level).
The ionized calcium level may provide a more accurate diagnosis of hypercalcemia, as the corrected total calcium level can be inaccurate in the setting of reduced GFR[CE12], in the presence of a paraprotein, or in the setting of acidosis.
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Up to 30% of patients with cancer develop hypercalcemia. The most common associated malignancies are breast cancer, lung cancer, and myeloma. The mechanisms by which cancer causes hypercalcemia include osteolytic metastases and increased bone resorption, tumor secretion of parathyroid hormone-related protein (PTHrP), and increased production of 1,25-dihydroxyvitamin D.
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Clinical presentation
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The severity of symptoms from hypercalcemia typically correlates with the degree of calcium level elevation and the acuity of rise. Patients with moderate hypercalcemia (corrected calcium ≥12 mg/dL) develop constipation, fatigue, and depressed mood. Progressive symptoms of polyuria, polydipsia, anorexia, nausea, weakness, lethargy, confusion, and coma may occur as the calcium level rises (corrected calcium ≥14 mg/dL). Acute hypercalcemia can cause QT shortening that can result in cardiac arrhythmias. Profound muscle weakness may also be a sign of acute, severe hypercalcemia. In general, hypercalcemia associated with malignancy portends a poor prognosis, as it is often attributable to large tumor burden or metastatic skeletal disease.
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