What is the treatment for hypocalcemia (low calcium levels)?

Treatment of Hypocalcemia

The treatment of hypocalcemia requires prompt administration of calcium supplementation, with intravenous calcium chloride being the preferred treatment for acute symptomatic hypocalcemia requiring a rapid increase in plasma calcium levels. 1, 2

Assessment and Diagnosis

• Calculate corrected calcium if using total serum calcium measurement:

  • Corrected calcium (mg/dL) = Total calcium (mg/dL) + 0.8 × [4 - Serum albumin (g/dL)] 1

• Assess for symptoms of hypocalcemia:

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

Treatment Algorithm

1. Acute Symptomatic Hypocalcemia

• First-line treatment: Intravenous calcium administration 1, 3, 2

  • Calcium chloride: Preferred for emergent situations requiring prompt increase in plasma calcium 2

    • More rapid and reliable increase in ionized calcium
    • Contains 3 times more elemental calcium than calcium gluconate

  • Calcium gluconate: Alternative IV option 3

    • For acute symptomatic hypocalcemia in both pediatric and adult patients
    • Dosing: 4g calcium gluconate infused at 1g/hour has been shown to effectively increase ionized calcium from 0.90 to 1.16 mmol/L in critically ill trauma patients 4

• Target: Maintain ionized calcium above 0.9 mmol/L 1

• Monitoring: Check ionized calcium levels frequently during acute treatment 1

2. Chronic Hypocalcemia Management

• Oral calcium supplementation:

  • Calcium carbonate: 1000-2000 mg elemental calcium daily in divided doses 1
  • Calcium citrate: Preferred over calcium carbonate due to better absorption, especially when taken between meals 1

• Vitamin D supplementation:

  • Cholecalciferol (Vitamin D3): 800-1000 IU daily 1
  • For severe cases or hypoparathyroidism: Active vitamin D (calcitriol) may be required 5

• For hypoparathyroidism:

  • Consider recombinant human PTH(1-84) for patients with difficult-to-control hypocalcemia 5
  • This therapy reduces daily requirements of calcium and active vitamin D supplements

• Monitoring:

  • Check calcium levels every 3-6 months until stable, then annually
  • Monitor 25-hydroxyvitamin D levels with target >30 ng/mL 1
  • For chronic kidney disease patients: More frequent monitoring (monthly for first 3 months, then every 3 months for stages 3-4) 1

Special Considerations

• Critically ill patients:

  • Remember that ionized calcium is pH-dependent (0.1 unit increase in pH decreases ionized calcium by ~0.05 mmol/L) 1
  • During massive transfusion: Maintain ionized calcium above 0.9 mmol/L 1

• Chronic kidney disease:

  • Patients with GFR below 60 mL/min/1.73 m² often show decreased blood levels of total and free calcium 6
  • Chronic hypocalcemia in dialysis patients is associated with increased mortality, cardiac ischemic disease, and heart failure 6

• Potential complications:

  • Overcorrection leading to hypercalcemia
  • Renal calculi formation
  • Calcinosis cutis and tissue necrosis with extravasation of IV calcium 1
  • Avoid concurrent use of calcium with ceftriaxone due to risk of precipitates 1

Underlying Cause Management

• Hypoparathyroidism (most common cause is post-surgical):

  • Calcium and vitamin D supplementation must be carefully titrated
  • Keep serum calcium in low-normal range to minimize hypercalciuria 7

• Vitamin D deficiency:

  • Higher doses of vitamin D supplementation may be required initially
  • Address underlying causes of vitamin D deficiency

• Other causes:

  • Magnesium deficiency: Supplement magnesium as needed
  • Chronic kidney disease: Manage according to CKD-specific guidelines
  • Medication-induced: Consider medication adjustments if possible

By following this treatment algorithm and addressing the underlying cause of hypocalcemia, clinicians can effectively manage both acute and chronic hypocalcemia while minimizing complications and improving patient outcomes.