Calcium Supplementation After Total Thyroidectomy
Routine postoperative oral calcium supplementation (1000-1500 mg three times daily) along with vitamin D (calcitriol 0.25-0.5 μg twice daily) is recommended for all patients after total thyroidectomy to prevent hypocalcemia.
Understanding Post-Thyroidectomy Hypocalcemia
Hypocalcemia is the most common complication following total thyroidectomy, occurring due to:
- Temporary or permanent hypoparathyroidism
- Surgical trauma to parathyroid glands
- Inadvertent removal of parathyroid glands
The incidence of transient hypocalcemia after total thyroidectomy ranges from 7-36% without supplementation 1, 2.
Recommended Supplementation Protocol
Immediate Postoperative Period (First 1-2 Weeks)
- Calcium supplementation: 1000-1500 mg elemental calcium three times daily 3, 2
- Vitamin D supplementation: Calcitriol 0.25-0.5 μg twice daily 3, 2
Monitoring Protocol
Check serum calcium levels at:
- 6 hours post-surgery
- 12 hours post-surgery
- 24 hours post-surgery
- 48 hours post-surgery
- 72 hours post-surgery
- 1 week post-surgery
- 1 month post-surgery
Monitor for symptoms of hypocalcemia:
- Perioral numbness
- Paresthesias in extremities
- Muscle cramps
- Tetany
- Positive Chvostek's or Trousseau's signs
Duration of Supplementation
- Continue supplementation for at least 1-2 weeks postoperatively
- Taper based on serum calcium levels at follow-up visits
- For patients with persistent hypocalcemia beyond 6 months, consider permanent hypoparathyroidism
Evidence Supporting This Approach
Multiple randomized controlled trials demonstrate that routine postoperative calcium and vitamin D supplementation significantly reduces the incidence of symptomatic hypocalcemia:
- Oral calcium supplementation alone reduced symptomatic hypocalcemia from 18.8% to 10.1% 1
- Combined calcium and vitamin D supplementation reduced symptomatic hypocalcemia from 25.9% to 6.8% 1
- In one study, routine calcium and vitamin D supplementation reduced symptomatic hypocalcemia from 24% to 7% 2
Preoperative Supplementation
The evidence regarding preoperative calcium and vitamin D supplementation is mixed:
- One retrospective study showed reduced symptomatic hypocalcemia (6% vs 16%) with preoperative supplementation 3
- However, a more recent randomized clinical trial found no significant difference in hypocalcemia rates between preoperative plus postoperative supplementation (13.2%) versus postoperative supplementation alone (15.9%) 4
Based on the most recent high-quality evidence, preoperative supplementation is not routinely recommended 4.
Special Considerations
For High-Risk Patients
Consider more aggressive supplementation for patients at higher risk of hypocalcemia:
- Total thyroidectomy with central neck dissection
- Graves' disease
- Reoperation
- Identified parathyroid injury during surgery
Management of Severe Hypocalcemia
For severe symptomatic hypocalcemia (ionized calcium <0.9 mmol/L):
- Administer IV calcium gluconate: 1-2 mg elemental calcium per kg body weight per hour 5, 6
- Monitor calcium levels every 1-4 hours during continuous infusion 5
- Transition to oral supplementation when stabilized
Practical Implementation Tips
- Start supplementation immediately after surgery before symptoms develop
- Administer calcium supplements between meals to maximize absorption
- Take calcium and iron supplements at least 2 hours apart as they may inhibit each other's absorption 7
- Consider calcium citrate for patients with achlorhydria or those taking proton pump inhibitors
- Monitor for signs of hypercalcemia if supplementation is prolonged
By following this protocol, the risk of symptomatic hypocalcemia can be significantly reduced, improving patient outcomes and potentially shortening hospital stays after total thyroidectomy.