From the EM Model:
1.0 Signs, Symptoms, and Presentations.
1.1 General

As the population ages and an increasing number of patients undergo aggressive chemotherapy, radiation therapy, and bone marrow transplantation, an increasing number of emergency department visits will be for patients with cancer-related problems. Some complications represent an immediate threat to the patient’s life or functional capacity. Some are treatable in ways that are lifesaving or may improve quality of life in a significant way.

Case Presentation

A 57-year-old man with a history of squamous cell carcinoma of the lung is brought in by his wife and eldest daughter because he has become unresponsive. He has been increasingly fatigued over the past 2 weeks but is now stuporous. Apart from some abdominal pain last week, he seems to have been pain-free. His wife reports that he has been chronically constipated and has been essentially bed-confined for several days. On examination he does not answer questions and seems oriented to name only.

Hypercalcemia

Hypercalcemia occurs frequently in patients with advanced malignancy; it has been reported in 10% to 30% of patients with cancer at some time during their disease.^1,2 The rate of rise of serum calcium concentration and the degree of hypercalcemia often determine symptoms and urgency of therapy.3 Patients with chronic hypercalcemia could be minimally symptomatic with levels of 15 mg/dL, while patients with acute hypercalcemia might present with coma with levels as low as 12 mg/dL. Acute hypercalcemia presents with central nervous system (CNS) effects ranging from mental status changes such as lethargy, paranoia, confusion, depression, and somnolence, to coma. Chronic hypercalcemia can present with constipation, polyuria, polydipsia, anorexia, nausea, memory loss, or a shortened QT interval on ECG.

Multiple factors may cause hypercalcemia of malignancy: elaboration of a parathyroid-hormone-related protein; local bone destruction; and tumor producing vitamin D-like substances.²

The most common malignancies associated with hypercalcemia are multiple myeloma, lung cancer, and breast cancer.^1,4 These patients may have other electrolyte abnormalities caused by hypokalemia or dehydration. Serum phosphorus, albumin, and alkaline phosphatase should be measured as well. In patients with hypoalbuminemia, total serum calcium concentration can be normal while serum ionized calcium is elevated. The measured total serum calcium should be added to 0.8x(4.0-[albumin]) to correct for hypoalbuminemia.⁴ A serum calcium level above 14 mg/dL generally constitutes a medical emergency requiring treatment even if the patient appears minimally symptomatic.

CRITICAL DECISION

What therapies are available in the emergency setting to treat hypercalcemia?