What is the treatment for hypocalcemia?

Treatment of Hypocalcemia

For acute symptomatic hypocalcemia, administer calcium chloride 10 mL of 10% solution (270 mg elemental calcium) intravenously with continuous ECG monitoring, as calcium chloride delivers three times more elemental calcium than calcium gluconate and is the preferred agent for immediate correction. 1

Acute Symptomatic Hypocalcemia

Immediate IV Calcium Administration

• Calcium chloride is superior to calcium gluconate because 10 mL of 10% calcium chloride contains 270 mg elemental calcium versus only 90 mg in the same volume of calcium gluconate 1, 2
• Calcium chloride is particularly preferred in patients with liver dysfunction due to faster release of ionized calcium 2
• Administer slowly while continuously monitoring ECG for cardiac arrhythmias, particularly QT prolongation and bradycardia 1
• Do NOT exceed infusion rates of 200 mg/minute in adults or 100 mg/minute in pediatric patients to prevent cardiac complications 3

Alternative IV Calcium Options

• If calcium chloride is unavailable, use calcium gluconate 10% solution 15-30 mL IV over 2-5 minutes 3
• For continuous infusion, dilute calcium gluconate to 5.8-10 mg/mL concentration in 5% dextrose or normal saline 1
• Administer through a secure IV line to prevent calcinosis cutis and tissue necrosis from extravasation 3

Critical Safety Precautions

• Never administer calcium through the same line as sodium bicarbonate due to precipitation risk 1
• Do not mix calcium with ceftriaxone as this creates dangerous calcium-ceftriaxone precipitates; concomitant use is absolutely contraindicated in neonates ≤28 days old 3
• Use extreme caution when phosphate levels are elevated (risk of calcium-phosphate precipitation in tissues) 1

Addressing Underlying Causes Simultaneously

Hypomagnesemia Correction (Essential First Step)

• Administer magnesium sulfate 1-2 g IV bolus immediately before calcium replacement if hypomagnesemia is present or suspected 1
• Hypomagnesemia causes hypocalcemia through two mechanisms: impaired PTH secretion and end-organ PTH resistance, explaining why calcium alone fails 1
• Continue magnesium supplementation (oral magnesium oxide 12-24 mmol daily) for chronic management 1

Vitamin D Deficiency

• Supplement with ergocalciferol (vitamin D2) when 25-hydroxyvitamin D is <30 ng/mL 2
• For severe or refractory cases with elevated PTH, use hormonally active vitamin D metabolites (calcitriol) requiring endocrinologist consultation 1, 2

Special Clinical Scenarios

• Trauma/massive transfusion patients: Hypocalcemia results from citrate in blood products binding calcium; citrate metabolism is impaired by hypoperfusion, hypothermia, and hepatic insufficiency 1
• Tumor lysis syndrome: Administer calcium gluconate 50-100 mg/kg IV slowly with ECG monitoring, but exercise extreme caution when phosphate is elevated 1
• Post-parathyroidectomy: Measure ionized calcium every 4-6 hours for first 48-72 hours, then twice daily until stable; initiate calcium gluconate infusion at 1-2 mg elemental calcium/kg/hour if ionized calcium falls below 0.9 mmol/L 1

Chronic Hypocalcemia Management

Daily Supplementation Regimen

• Provide daily calcium carbonate 1-2 g three times daily plus vitamin D supplementation for all patients with chronic hypocalcemia 1, 2
• Calcium carbonate contains the highest percentage of elemental calcium among oral formulations 2
• Total elemental calcium intake (dietary plus supplements) must not exceed 2,000 mg/day to prevent vascular calcification and renal complications 1, 2
• For patients requiring calcium-based phosphate binders, limit elemental calcium from binders to ≤1,500 mg/day 1

Target Calcium Levels

• Maintain serum calcium in the low-normal range (8.4-9.5 mg/dL) to minimize hypercalciuria and prevent renal dysfunction 1, 2
• In CKD stage 5 patients, target corrected total serum calcium toward the lower end of normal range 1
• Keep calcium-phosphorus product <55 mg²/dL² to prevent vascular calcification 1

Monitoring Requirements

• Measure pH-corrected ionized calcium, magnesium, PTH, and creatinine regularly 1, 2
• During acute IV treatment, measure serum calcium every 4-6 hours for intermittent infusions and every 1-4 hours for continuous infusions 3
• Intensify monitoring during vulnerable periods: perioperatively, perinatally, during pregnancy, acute illness, surgery, childbirth, and infection 1, 2

Critical Pitfalls to Avoid

• Avoid overcorrection, which causes iatrogenic hypercalcemia, renal calculi, and renal failure 1, 2
• Do not use calcium-based phosphate binders when corrected serum calcium >10.2 mg/dL or plasma PTH <150 pg/mL on two consecutive measurements 1
• Recognize that dehydration can inadvertently cause overcorrection, and changes in calcitriol compliance can lead to unexpected hypercalcemia 1

Special Population: 22q11.2 Deletion Syndrome (DiGeorge)

• 80% have lifetime history of hypocalcemia due to hypoparathyroidism, which may arise or recur at any age despite apparent childhood resolution 1, 2
• Provide daily calcium and vitamin D supplementation universally for all adults with this syndrome 1, 2
• Advise patients to avoid alcohol and carbonated beverages (especially colas) as they worsen hypocalcemia 1
• Biological stressors (surgery, fracture, injury, childbirth, infection) can precipitate acute hypocalcemia requiring heightened surveillance 1

Renal Impairment Considerations

• Initiate calcium gluconate at the lowest recommended dose and monitor serum calcium every 4 hours 3
• Use individualized approach rather than routine correction in all CKD patients 1
• Adjust dialysate calcium concentration (standard 2.5 mEq/L; up to 3.5 mEq/L when calcium supply needed) based on patient requirements 1