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Hypercalcemia

Rebecca Choudhry and Trevor Stevens

Background

  • Total serum Calcium >10.5

  • Most (99%) Ca+2 is anhydrous and stored in bone. The remaining 1% is 60% bound (mostly to albumin), and 40% ionized and able to exert a physiologic effect

  • Remember, there is an inverse relationship between pH and Ca2+. As pH declines, serum Ca increases due to H+ binding to albumin and releasing Ca2+

  • Don’t forget to correct calcium level if hypoalbuminemia (or check ionized calcium level),

    • Corrected Ca2+ = ((Normal albumin – Patient’s albumin) x 0.8)) + Patient’s Ca2+

      • This equation Is less reliable at very low albumin

Presentation

  • Ca+2 > 12 can cause shortened QT interval, 2nd and 3rd degree heart block, ventricular arrhythmias, and ST elevations mimicking MI

  • Severe manifestations uncommon at Ca+2 \<14

  • “Stones, bones, thrones, belly groans, and psychiatric overtones”

    • Bone pain

    • Polydipsia/polyuria- due to nephrogenic DI

    • Nausea/constipation

    • Depressed mood/cognitive impairment

    • Decreased level of consciousness

Evaluation

  • Measure PTH

    • Normal or ↑ PTH

      • Primary hyperparathyroidism: ↑ Ca+2 and ↓ PO4-3

      • Tertiary hyperparathyroidism (autologous secretion of PTH in CKD/ESRD)

      • Familial hypercalciuric hypercalcemia (often asymptomatic, no treatment required).

      • Li toxicity

    • ↓ PTH

      • Humoral hypercalcemia of malignancy (PTHrP)

      • Malignancy (boney metastases)

      • Excess vitamin D intake

      • Granulomatous disease: 1,25 dihydroxy vitamin D, 25 hydroxyvitamin D, or ACE level

      • Milk-alkali syndrome

      • Medications (classically HCTZ)

      • Thyrotoxicosis

      • Adrenal insufficiency

Management

  • If Ca+2 \< 12 and asymptomatic

    • Encourage PO hydration

    • Normal saline if hypovolemic

    • Evaluate for underlying cause

  • If Ca+2 > 12 with symptoms or Ca > 14

    • Trend Ca q8 hrs, EKG, monitor on telemetry; strict I/Os ± foley catheter

    • Volume expansion w/ NS bolus followed by continuous infusion at ~ 200cc/hr

      • Goal UOP 100-150cc/hr

    • Add loop diuretic (Lasix) once patient is volume expanded

    • Bisphosphonates

      • Zoledronic acid 4mg IV (EGFR >60), Pamidronate 90mg IV (EGFR 15-60)

  • If Ca+2 >14 or neurologic symptoms, consider subq (not intranasal) calcitonin

    • VUMC: requires approval from an oncology or endocrine attending

    • Tachyphylaxis after ~48H

  • Additional Information

    • In CHF pt, consider early addition of a loop diuretic, especially if volume overloaded

    • In ESRD pt with hypercalcemia (rare), patient with oliguric AKI not responsive to IVF, or pt with severely elevated Ca 16-18, consult endocrine and nephrology early

    • In pts with sarcoidosis or lymphoma, consider glucocorticoids