From the Research
The British guidelines for treating hypocalcaemia in patients with hyperthyroidism recommend prompt calcium replacement therapy, particularly in symptomatic patients, with the most recent and highest quality study suggesting that treatment should be tailored to the individual patient's needs, taking into account the underlying cause of hypocalcaemia and the presence of any underlying vitamin D deficiency 1.
Key Recommendations
- Initial management includes intravenous calcium gluconate 10% (10-20 ml over 10 minutes) for severe symptoms, followed by a continuous infusion of calcium gluconate in normal saline at 1-2 mg/kg/hour elemental calcium.
- For oral maintenance therapy, calcium carbonate 2-3g daily in divided doses is recommended, along with active vitamin D (calcitriol 0.25-1 mcg daily or alfacalcidol 0.5-2 mcg daily).
- In hyperthyroid patients, hypocalcaemia often occurs during treatment of thyrotoxicosis, particularly in those with underlying vitamin D deficiency, so vitamin D supplementation (cholecalciferol 800-4000 IU daily) should be added.
- Magnesium levels should be checked and corrected if low, as hypomagnesaemia can impair parathyroid hormone action.
Rationale
The treatment of hypocalcaemia in patients with hyperthyroidism is crucial to prevent complications such as tetany, seizures, and cardiac arrhythmias. The British guidelines recommend a tailored approach to treatment, taking into account the underlying cause of hypocalcaemia and the presence of any underlying vitamin D deficiency. The use of intravenous calcium gluconate and oral calcium carbonate, along with active vitamin D, is recommended to rapidly correct serum calcium levels and prevent long-term complications.
Evidence Base
The evidence base for the treatment of hypocalcaemia in patients with hyperthyroidism is largely based on expert opinion and clinical experience, with limited high-quality studies available 2. However, the most recent and highest quality study suggests that treatment should be tailored to the individual patient's needs, taking into account the underlying cause of hypocalcaemia and the presence of any underlying vitamin D deficiency 1.
Considerations
- The treatment of hypocalcaemia in patients with hyperthyroidism should be individualized, taking into account the underlying cause of hypocalcaemia and the presence of any underlying vitamin D deficiency.
- Regular monitoring of serum calcium, phosphate, magnesium, and renal function is essential to prevent complications and adjust treatment as needed.
- The use of recombinant parathyroid hormone may be considered in patients with severe hypocalcaemia or those who are refractory to conventional treatment 1.