Hypocalcemia Correction
For hypocalcemia correction, calcium chloride is the preferred agent for emergency treatment due to its higher elemental calcium content compared to calcium gluconate. 1, 2
Diagnosis and Definition
- Hypocalcemia is defined as ionized calcium <0.9 mmol/L or serum total corrected calcium <7.5 mg/dL 2
- Clinical manifestations include:
- Neuromuscular symptoms: tetany, paresthesias, muscle cramps
- Cardiac symptoms: QT prolongation, arrhythmias
- Neuropsychiatric symptoms: fatigue, irritability, confusion
- Severe cases: seizures, abnormal involuntary movements 2
Acute Treatment Options
Intravenous Calcium Administration
Calcium Chloride (Preferred for Emergency Situations)
- 10 mL of 10% calcium chloride contains 270 mg of elemental calcium 1, 2
- Indicated for treatment of hypocalcemia requiring prompt increase in plasma calcium levels 3
- Preferred in emergency situations and in patients with liver dysfunction (where citrate metabolism is impaired) 1
Calcium Gluconate (Alternative)
- 10 mL of 10% calcium gluconate contains only 90 mg of elemental calcium 1, 2
- Contains 100 mg of calcium gluconate per mL (9.3 mg of elemental calcium per mL) 4
- Less preferred in emergency situations due to lower elemental calcium content
Administration Guidelines
- Administer calcium chloride slowly with ECG monitoring 2
- Do not exceed 200 mg/minute in adults 2
- For calcium gluconate, do not exceed 200 mg/minute in adults or 100 mg/minute in pediatric patients 2
- Avoid mixing calcium with phosphate or bicarbonate-containing fluids due to precipitation risk 2, 4
Monitoring During Treatment
- For IV calcium administration:
- Monitor ionized calcium during intermittent infusions every 4-6 hours
- During continuous infusion, monitor every 1-4 hours 2
- During massive transfusion, monitor ionized calcium levels closely as citrate in blood products can chelate calcium 1, 2
- Maintain ionized calcium within normal range (1.1-1.3 mmol/L) 1
Chronic Management
- Elemental calcium 1-2 g/day divided into multiple doses 2
- Common oral formulations:
- Calcium carbonate (40% elemental calcium)
- Calcium citrate (21% elemental calcium) 2
- Monitor serum calcium every 2-4 weeks initially, then every 3-6 months once stable 2
- Maintain calcium-phosphorus product <55 mg²/dL 2
Special Considerations
- Trauma patients: Hypocalcemia is common and associated with increased mortality and need for massive transfusion 1, 2
- Massive transfusion: Citrate in blood products chelates calcium, requiring close monitoring and replacement 1, 2
- Post-parathyroidectomy: May require aggressive calcium replacement due to hungry bone syndrome 2
- Chronic kidney disease: Requires individualized approach 2
Common Pitfalls and Caveats
- Avoid administering calcium if phosphate levels are elevated due to risk of calcium phosphate precipitation in tissues 2
- Use caution when administering calcium with cardiac glycosides due to risk of arrhythmias 2
- Avoid overcorrection of hypocalcemia, which can lead to hypercalcemia, kidney stones, and renal failure 2
- Verify true hypocalcemia, as hypoalbuminemia can artificially lower total calcium levels without affecting ionized calcium 5
- Treatment response can be highly variable between patients, particularly in those with moderate to severe hypocalcemia 6