What is the management of hypocalcemia?

Management of Hypocalcemia

The management of hypocalcemia requires prompt administration of calcium chloride to correct low ionized calcium levels, especially during massive transfusion and in critically ill trauma patients. 1, 2

Diagnosis and Assessment

• Monitor ionized calcium levels in patients at risk for hypocalcemia:

  • Trauma patients, especially those receiving massive transfusion
  • Patients with hypoparathyroidism
  • Patients with vitamin D deficiency

• Calculate corrected calcium if using total calcium measurement:

  • Corrected calcium (mg/dL) = Total calcium (mg/dL) + 0.8 × [4 - Serum albumin (g/dL)] 3

• Assess for symptoms of hypocalcemia:

  • Neuromuscular irritability
  • Paresthesia
  • Tetany
  • Seizures
  • Cardiac dysrhythmias (when ionized Ca²⁺ < 0.8 mmol/L) 1

Acute Management

Severe Symptomatic Hypocalcemia

• Intravenous calcium chloride is the preferred treatment for acute hypocalcemia requiring prompt increase in plasma calcium levels 1, 2

  • Initial dose: 10% calcium chloride solution (1 g contains 272 mg elemental calcium)
  • Administer at a rate of 1 g/hour 4
  • For moderate to severe hypocalcemia (ionized calcium < 1 mmol/L), a 4 g calcium gluconate infusion is effective in 95% of cases 4

• Administration precautions:

  • Infuse into large veins or via central line
  • Dilute in appropriate volume of solution
  • Stop infusion if patient complains of tenderness at injection site
  • Monitor for extravasation which can cause skin necrosis 5

Mild to Moderate Hypocalcemia

• For mild hypocalcemia (ionized calcium 1.0-1.12 mmol/L):
  • 1-2 g IV calcium gluconate is effective in 79% of patients 6
  • Monitor ionized calcium levels the following day

Chronic Management

• Oral calcium supplementation:

  • Calcium citrate (preferred due to better absorption) or calcium carbonate
  • Dosage: 1000-2000 mg elemental calcium daily in divided doses 3

• Vitamin D supplementation:

  • Cholecalciferol (Vitamin D3): 800-1000 IU daily for maintenance
  • For vitamin D deficiency (<20 ng/mL), higher doses may be needed 3
  • For severe deficiency, consider ergocalciferol 50,000 IU weekly for 12 weeks 3

• For hypoparathyroidism:

  • Consider calcitriol (active vitamin D) for management of hypocalcemia 7
  • Carefully titrate calcium and vitamin D to maintain serum calcium in low-normal range 8

Monitoring

• During acute treatment:

  • Monitor ionized calcium levels frequently
  • Monitor ECG for signs of hypocalcemia or hypercalcemia
  • Watch for signs of calcium extravasation

• Long-term monitoring:

  • Check calcium levels every 3-6 months until stable, then annually 3
  • Monitor 25-hydroxyvitamin D levels with target >30 ng/mL 3
  • For patients with chronic kidney disease:
    • Stages 3-4: Monitor calcium monthly for first 3 months, then every 3 months 3
    • Stage 5 (dialysis): Monitor calcium every 2 weeks for 1 month, then monthly 3

Special Considerations

• Massive transfusion: Citrate in blood products chelates calcium, causing hypocalcemia

  • Maintain ionized calcium above 0.9 mmol/L 1
  • Citrate metabolism may be impaired by hypoperfusion, hypothermia, or hepatic insufficiency 1

• Medication interactions:

  • Separate calcium supplements from levothyroxine by at least 4 hours 3
  • Avoid concurrent use with ceftriaxone due to risk of precipitates 3
  • Use caution with cardiac glycosides due to increased risk of arrhythmias 3

Complications of Treatment

• Overcorrection leading to hypercalcemia
• Renal calculi formation
• Renal dysfunction
• Calcinosis cutis and tissue necrosis with extravasation of IV calcium 5

Remember that ionized calcium is pH-dependent, with a 0.1 unit increase in pH decreasing ionized calcium concentration by approximately 0.05 mmol/L 1. This is particularly important in critically ill patients who may have acid-base disturbances.