What is the treatment for hypocalcemia?

Treatment of Hypocalcemia

For symptomatic hypocalcemia, immediate treatment with intravenous calcium is recommended, with calcium chloride being the preferred agent due to its higher elemental calcium content compared to calcium gluconate. 1

Assessment and Diagnosis

• Monitor ionized calcium levels in high-risk patients (massive transfusion, trauma, hypoparathyroidism, 22q11.2 deletion syndrome)
• Normal ionized calcium range: 1.1-1.3 mmol/L
• Hypocalcemia defined as:
  • Mild: ionized calcium 1.0-1.12 mmol/L
  • Moderate to severe: ionized calcium <1.0 mmol/L

Treatment Algorithm

Asymptomatic Hypocalcemia

• For mild asymptomatic hypocalcemia: Monitor closely without immediate intervention 1
• For patients at risk of recurrent hypocalcemia (e.g., 22q11.2 deletion syndrome):
  • Daily calcium and vitamin D supplementation 1
  • Regular monitoring of calcium, magnesium, parathyroid hormone, and creatinine levels

Symptomatic Hypocalcemia

Immediate Treatment

1. Intravenous calcium administration:

   • Calcium chloride is preferred (10 mL of 10% solution contains 270 mg elemental calcium) 1, 2
   • Alternative: Calcium gluconate (10 mL of 10% solution contains only 90 mg elemental calcium) 3
   • Dosing:
     • For mild hypocalcemia (1.0-1.12 mmol/L): 1-2 g IV calcium gluconate 4
     • For moderate to severe hypocalcemia (<1.0 mmol/L): 4 g IV calcium gluconate infused at 1 g/hour 5

2. Administration considerations:

   • Administer calcium chloride via slow IV infusion with ECG monitoring 1
   • Do not administer calcium and sodium bicarbonate through the same line 1

Specific Clinical Scenarios

1. Massive Transfusion/Trauma:

   • Monitor ionized calcium levels throughout transfusion 1
   • Administer calcium chloride if ionized calcium levels are low or ECG changes suggest hypocalcemia 1
   • Target ionized calcium >0.9 mmol/L 1

2. Tumor Lysis Syndrome:

   • For symptomatic patients: calcium gluconate 50-100 mg/kg IV administered slowly with ECG monitoring 1
   • Use caution if phosphate levels are high due to risk of calcium phosphate precipitation 1

3. 22q11.2 Deletion Syndrome:

   • Daily calcium and vitamin D supplementation for all adults 1
   • Magnesium supplementation for those with hypomagnesemia 1
   • For severe hypocalcemia: treatment with hormonally active metabolites of vitamin D (consult endocrinologist) 1

Important Considerations

• Calcium chloride advantages over calcium gluconate:

  • Higher elemental calcium content (270 mg vs 90 mg per 10 mL of 10% solution) 1
  • More effective in patients with liver dysfunction (where citrate metabolism is impaired) 1

• Monitoring:

  • Repeat ionized calcium measurement within 24 hours after treatment 4, 5
  • Monitor ECG for cardiac effects of hypocalcemia (prolonged QT interval) 1

• Cautions:

  • Avoid over-correction which can lead to hypercalcemia, renal calculi, and renal failure 1
  • Use caution when administering calcium in patients with high phosphate levels 1
  • Address underlying causes (hypoparathyroidism, vitamin D deficiency, etc.) 6

• Factors affecting calcium levels:

  • pH changes (0.1 unit increase in pH decreases ionized calcium by 0.05 mmol/L) 1
  • Citrate in blood products can chelate calcium 1
  • Biological stress (surgery, childbirth, infection) can worsen hypocalcemia 1

By following this algorithm, clinicians can effectively manage hypocalcemia while minimizing complications and addressing the underlying causes of this potentially life-threatening condition.