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Source: Pai AB. Disorders of calcium and phosphorus homeostasis. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861§ionid=146061894. Accessed August 10, 2017.
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Incidence of primary hyperparathyroidism in United States ranges 10–30 cases per 100,000 people; primarily occurs in outpatients.
Hypercalcemia of cancer occurs in ~20–40% of patients at some time in course of disease and predominantly seen in inpatients.
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Cancer.
Immobilization.
Medications.
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CLINICAL PRESENTATION
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Mild to moderate hypercalcemia (serum calcium <13 mg/dL [3.25 mmol/L]): often asymptomatic.
Severe hypercalcemia (serum calcium >13 mg/dL [3.25 mmol/L]):
Rapid onset (eg, hypercalcemia of malignancy)
Anorexia.
Nausea and vomiting.
Constipation.
Polyuria.
Polydipsia.
Nocturia.
Hypercalcemic crisis.
Acute increase in serum calcium to >15 mg/dL [>3.75 mmol/L])
Acute renal insufficiency.
Obtundation.
If untreated, progresses to oliguric renal failure, coma, and life-threatening ventricular arrhythmias.
Chronic hypercalcemia (eg, hyperparathyroidism)
Electrocardiogram (ECG) changes include shortening of QT interval and coving of ST-T wave.
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MEANS OF CONFIRMATION AND DIAGNOSIS
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Metabolic panel.
Serum calcium.
Corrected total serum calcium calculated as follows:
Corrected Sca (mg/dL) = measured Sca (mg/dL) + [0.8 × (40 g/dL – measured albumin (g/dL))] or Corrected Sca (mmol/dL) = measured Sca (mmol/dL) + [0.02 × (40 g/L – measured albumin (g/L))]
Serum albumin.
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DIAGNOSTIC PROCEDURES
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DIFFERENTIAL DIAGNOSIS
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Hyperparathyroidism.
Sarcoidosis.
Renal tubular acidosis.
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