What is the treatment for hypocalcemia?

Treatment of Hypocalcemia

For acute symptomatic hypocalcemia, administer intravenous calcium gluconate immediately, while chronic hypocalcemia requires oral calcium and vitamin D supplementation with careful monitoring to avoid overcorrection.

Acute Symptomatic Hypocalcemia

Severity Classification

• Severe hypocalcemia is defined as total corrected calcium ≤7.5 mg/dL or ionized calcium <0.9 mmol/L 1
• Normal ionized calcium ranges from 1.1 to 1.3 mmol/L, with total corrected calcium below 8.4 mg/dL (2.10 mmol/L) indicating hypocalcemia 1

Immediate IV Treatment

• Administer calcium gluconate intravenously for symptomatic patients, which is FDA-approved for acute symptomatic hypocalcemia 2
• Dilute calcium gluconate to a concentration of 10-50 mg/mL in 5% dextrose or normal saline prior to bolus administration 2
• Infusion rate must NOT exceed 200 mg/minute in adults or 100 mg/minute in pediatric patients to prevent cardiac complications 2
• Monitor ECG continuously during administration for cardiac arrhythmias 3, 2
• Each 10 mL of 10% calcium gluconate contains 100 mg calcium gluconate, which provides 9.3 mg (0.465 mEq) of elemental calcium 2

Calcium Chloride Considerations

• Calcium chloride may be preferred over calcium gluconate in patients with liver dysfunction due to faster release of ionized calcium 1
• 10 mL of 10% calcium chloride contains 270 mg of elemental calcium versus only 90 mg in 10 mL of 10% calcium gluconate, making it three times more potent 1, 3
• This is particularly relevant in critical care settings where rapid correction is needed 3

Monitoring During Acute Treatment

• Measure serum calcium every 4 to 6 hours during intermittent infusions 2
• Measure serum calcium every 1 to 4 hours during continuous infusion 2
• Use a secure intravenous line to avoid calcinosis cutis and tissue necrosis from extravasation 2

Critical Cautions

• Never mix calcium gluconate with ceftriaxone, as this can lead to fatal ceftriaxone-calcium precipitates 2
• Avoid calcium administration through the same line as sodium bicarbonate 3
• Use extreme caution when phosphate levels are elevated due to risk of calcium phosphate precipitation in tissues 3

Chronic Hypocalcemia Management

Standard Oral Therapy

• Daily calcium and vitamin D supplementation are the cornerstone of chronic hypocalcemia treatment 1, 3, 4
• Calcium carbonate is commonly used and contains the highest percentage of elemental calcium 1
• For vitamin D deficiency (25-hydroxyvitamin D <30 ng/mL), supplement with ergocalciferol (vitamin D2) 1
• For more severe hypocalcemia, hormonally active metabolites of vitamin D (calcitriol) may be required 1

Special Consideration for Achlorhydria

• In patients refractory to massive doses of calcium carbonate and vitamin D, consider achlorhydria as the underlying cause 5
• Oral calcium chloride solution can promptly correct hypocalcemia in patients with achlorhydria who are unresponsive to calcium carbonate 5
• Monitor serum chloride and CO2 to avoid hyperchloremic acidosis when using calcium chloride 5

Dosing Limits in CKD Patients

• In CKD patients, total elemental calcium intake (including dietary calcium and calcium-based phosphate binders) should not exceed 2,000 mg/day 1
• Use an individualized approach to correct hypocalcemia in CKD patients rather than universal correction, particularly in those on calcimimetics 6
• Patients with significant or symptomatic hypocalcemia should still receive correction to prevent adverse consequences 6

Monitoring Parameters

• Regular monitoring of pH-corrected ionized calcium, magnesium, parathyroid hormone, and creatinine is essential 1, 3
• Targeted monitoring during vulnerable periods: perioperatively, perinatally, and during severe illness 1, 3
• Correct hypomagnesemia when present, as it contributes to hypocalcemia and impairs PTH secretion 3, 4

Renal Impairment Dosing

• For patients with renal impairment, initiate calcium gluconate at the lowest recommended dose and monitor serum calcium every 4 hours 2

Critical Pitfalls to Avoid

• Avoid overcorrection, which can result in iatrogenic hypercalcemia, renal calculi, and renal failure 1, 3
• In hypoparathyroidism, keep serum calcium in the low-normal range to minimize hypercalciuria and prevent renal dysfunction 4
• Hypocalcemia in critically ill patients correlates with severity of illness and mortality, occurring in up to 88% of ICU patients 7
• In trauma patients, hypocalcemia is often due to citrate in blood products binding calcium, with citrate metabolism impaired by hypoperfusion, hypothermia, and hepatic insufficiency 3

Underlying Cause Management

• Address the underlying etiology while providing symptomatic treatment: hypoparathyroidism (most common cause post-surgically), vitamin D deficiency, hypomagnesemia, or CKD-mineral bone disorder 3, 4, 8
• For patients with 22q11.2 deletion syndrome (DiGeorge syndrome), hypocalcemia typically requires lifelong calcium and vitamin D supplementation 1