Treatment of Hypocalcemia
For symptomatic hypocalcemia, calcium chloride is the preferred agent for immediate correction, administered intravenously at a dose of 10 mL of 10% solution (containing 270 mg elemental calcium) for adults. 1
Acute Treatment Based on Severity
Symptomatic Hypocalcemia
- For symptomatic patients, administer calcium intravenously 1:
- Calcium gluconate: 50-100 mg/kg IV administered slowly with ECG monitoring
- Calcium chloride is preferred over calcium gluconate due to higher elemental calcium content (10 mL of 10% calcium chloride contains 270 mg elemental calcium vs. 10 mL of 10% calcium gluconate containing only 90 mg) 1
- Administer slowly while monitoring ECG for cardiac arrhythmias 1
Moderate to Severe Hypocalcemia (ionized calcium < 0.9 mmol/L)
- Requires prompt correction, especially when ionized calcium levels are below 0.8 mmol/L due to risk of cardiac dysrhythmias 1
- For adults with ionized calcium < 1 mmol/L, infusion of 4g calcium gluconate at 1g/hour has shown 95% success rate in raising calcium levels above 1 mmol/L 2
- For trauma patients receiving massive transfusion, calcium chloride should be administered if ionized calcium levels are low or if ECG changes suggest hypocalcemia 1
Mild Hypocalcemia (ionized calcium 1-1.12 mmol/L)
- For mild cases, 1-2g of IV calcium gluconate is effective in normalizing ionized calcium in approximately 79% of patients 3
- Maintain ionized calcium levels above 0.9 mmol/L, especially in trauma patients requiring massive transfusion 1
Administration Guidelines
For bolus administration 4:
- Dilute calcium gluconate in 5% dextrose or normal saline to a concentration of 10-50 mg/mL
- Administer at a rate not exceeding 200 mg/minute in adults or 100 mg/minute in pediatric patients
- Monitor vital signs and ECG during administration
For continuous infusion 4:
- Dilute calcium in 5% dextrose or normal saline to a concentration of 5.8-10 mg/mL
- Monitor serum calcium every 4-6 hours during intermittent infusions and every 1-4 hours during continuous infusion
Special Considerations
Trauma and Massive Transfusion
- Monitor ionized calcium levels during massive transfusion 1
- Hypocalcemia in trauma patients is often due to citrate in blood products binding calcium 1
- Early hypocalcemia following traumatic injury correlates with the amount of colloids and blood products infused 1
- Citrate metabolism may be impaired by hypoperfusion, hypothermia, and hepatic insufficiency 1
Underlying Causes
- Address the underlying cause of hypocalcemia while providing acute treatment 5:
- Hypoparathyroidism (surgical or primary)
- Vitamin D deficiency
- Hypomagnesemia (correct if present) 1
Cautions
- Avoid calcium administration through the same line as sodium bicarbonate 1
- Use caution when phosphate levels are high due to risk of calcium phosphate precipitation in tissues 1
- For patients with renal impairment, start at the lowest dose and monitor serum calcium levels more frequently 4
- Avoid over-correction which can lead to iatrogenic hypercalcemia, renal calculi, and renal failure 1
Long-term Management
- Daily calcium and vitamin D supplementation for chronic hypocalcemia 1
- For severe hypocalcemia due to hypoparathyroidism, treatment with hormonally active metabolites of vitamin D may be required (consult endocrinologist) 1
- Regular monitoring of pH-corrected ionized calcium, magnesium, parathyroid hormone, and creatinine concentrations 1
- Targeted monitoring of calcium concentrations during vulnerable periods (peri-operative, perinatal, or during severe illness) 1
Specific Clinical Scenarios
Tumor Lysis Syndrome
- For asymptomatic patients, no intervention is recommended 1
- For symptomatic patients, administer calcium gluconate 50-100 mg/kg IV slowly with ECG monitoring 1
- Use caution with calcium replacement when phosphate levels are high 1