Management of Hypocalcemia
The management of hypocalcemia should focus on prompt correction with calcium chloride for severe or symptomatic cases, while using an individualized approach based on the underlying cause and severity of the condition. 1, 2
Assessment and Classification
- Hypocalcemia is defined as serum calcium level <8 mg/dl (2.12 mmol/L), with ionized calcium below 1.1 mmol/L 3
- Severe hypocalcemia is characterized by ionized calcium levels below 0.8 mmol/L and is associated with cardiac dysrhythmias requiring prompt correction 1
- Measurement of ionized calcium is critical in determining true calcium status, especially in critically ill patients with hypoalbuminemia or acid-base disorders 4
Acute Management of Severe/Symptomatic Hypocalcemia
Intravenous Calcium Administration
- For severe hypocalcemia (ionized calcium <0.8 mmol/L) or symptomatic patients, administer intravenous calcium immediately 1, 5
- Calcium chloride is preferred over calcium gluconate in emergency situations and in patients with liver dysfunction 1
- 10 mL of 10% calcium chloride contains 270 mg of elemental calcium
- 10 mL of 10% calcium gluconate contains only 90 mg of elemental calcium
- In trauma patients with hypocalcemia, prompt correction is essential as low calcium levels are associated with platelet dysfunction, decreased clot strength, increased blood transfusion requirements, and higher mortality 6, 1
Special Considerations for Massive Transfusion
- During massive transfusion, continuous IV calcium is required due to citrate-mediated chelation of serum calcium 6, 1
- Each unit of packed red blood cells or fresh frozen plasma contains approximately 3g of citrate that chelates calcium 6
- Monitor ionized calcium levels frequently during massive transfusion 6
Management of Chronic Hypocalcemia
Hypoparathyroidism
- Oral calcium and vitamin D supplementation are the mainstays of treatment 3
- Recombinant human PTH(1-84) has been approved by FDA and EMA for treatment of chronic hypoparathyroidism when standard therapy is inadequate 3
Chronic Kidney Disease Considerations
- In CKD patients, an individualized approach is recommended 6
- Significant or symptomatic hypocalcemia should be corrected, but routine correction of mild asymptomatic hypocalcemia is not universally recommended 6, 1
- For patients on dialysis, maintain dialysate calcium concentration between 1.25 and 1.50 mmol/L (2.5 and 3.0 mEq/L) 6
Hypocalcemia in Cancer Patients
- For hypercalcemia of malignancy, bisphosphonates (IV pamidronate or zoledronic acid) are effective 6
- Parenteral hydration with normal saline not only corrects hypercalcemia-associated hypovolemia but also promotes calciuresis 6
- For refractory cases, denosumab may be considered (approved by FDA but not EMA for this indication) 6
Monitoring During Treatment
- ECG monitoring is particularly important during rapid calcium administration 1
- Monitor phosphate levels concurrently with calcium levels to avoid calcium phosphate precipitation 1
- Do not administer calcium and sodium bicarbonate through the same line due to precipitation risk 1
- For patients with renal impairment, initiate calcium at the lowest recommended dose and monitor serum calcium levels every 4 hours 7
Long-term Management
- Identify and treat the underlying cause of hypocalcemia for definitive management 8
- For chronic hypocalcemia, oral calcium and vitamin D supplementation should be titrated to maintain serum calcium in the low-normal range while minimizing hypercalciuria 9
- In hypoparathyroidism, careful titration of calcium and vitamin D is necessary to avoid symptoms while preventing renal dysfunction from hypercalciuria 9