Hypercalcaemia in CKD
In established CKD, hypercalcaemia is usually caused by the prescription of vitamin D derivatives (e.g. alfacalcidol) and calcium-containing phosphate binders. Less frequently, it results from the development of tertiary hyperparathyroidism. In most cases, reducing / discontinuing implicated medications is sufficient, but be cautious if the patient is on a significant dose of vitamin D or has had a parathyroidectomy – calcium levels may plummet precipitously.
Hypercalcaemia in AKI
In AKI, calcium is usually low-normal. A high-normal or high calcium should lead to suspicion that the renal problem is caused by hypercalcaemia itself, or by the same disease as is responsible for hypercalcaemia, e.g., myeloma or sarcoidosis.
Treatment of Hypercalcaemia
- Fluid repletion: Hypercalcaemia drives an osmotic diuresis and can result in renal impairment due to dehydration. Fluid repletion, typically with 0.9% NaCl, will improve the renal impairment caused by hypercalcaemia, and has a small effect on reducing calcium level.
- Diuretics: Whilst loop diuretics do cause calciuria and may therefore lower serum calcium levels, they should be avoided unless adequate volume expansion has been achieved. Thereafter, they can be trialled with caution.
- Corticosteroids: These are effective in treatment of hypercalcaemia caused by sarcoidosis, some haematological malignancies, and – allegedly – also in vitamin D poisoning.
- Bisphosphonates: These drugs are effective in the management of severe hypercalcaemia. Calcium level will begin to fall over days, reaching a nadir at 3-5 days, and usually remaining suppressed for several weeks, when the infusion can be repeated. Bisphosphonates should be used with caution in renal impairment. High doses of pamidronate may be nephrotoxic – associated with proteinuria and FSGS.
- For dialysis patients, adjusting calcium content of dialysate may be helpful but choices of dialysate are limited.
Acknowledgements: Neil Turner was the main author for this page. It was updated by Ashley Simpson in November 2020. The last modified date is shown in the footer.