Management of severe hypercalcaemia secondary to primary hyperparathyroidism: The efficacy of saline hydration, furosemide, and zoledronic acid

Introduction: Severe hypercalcaemia is a life-threatening condition that should be managed urgently. The aim of this study was to assess the efficacy of saline hydration, furosemide, and zoledronic acid in the management of severe hypercalcaemia secondary to primary hyperparathyroidism (PHPT).

Methods: We conducted a retrospective analysis of the management of 65 patients with severe hypercalcaemia (≥3 mmol/L) secondary to PHPT. The efficacy of each therapeutic agent was evaluated according to the variation in serum calcium level calculated as Δ calcium = initial calcium level - minimal calcium level reached after the administration of each agent.

Results: The mean age of patients was 56.4 ± 13.8 years. At baseline, the mean total serum calcium level was 3.42 ± 0.40 mmol/L. After normal saline hydration, calcium level decreased from 3.25 ± 0.21 to 2.98 ± 0.2 mmol/L (p < 10^-3 ) in 3.1 ± 1.7 days. Normalization of calcium level did not occur in any patient. Furosemide was prescribed in 35 patients. It resulted in a serum calcium increase of 0.09 ± 0.21 mmol/L. Calcium levels did not reach the normal range in any patient. Forty-five patients received intravenous zoledronic acid. The mean maximal reduction in serum calcium level was 0.57 ± 0.27 mmol/L (from 3.25 ± 0.26 mmol/L to 2.68 ± 0.22 mmol/L, p-value <10^-3 ). Normalization of calcium levels occurred in 27 patients (60%).

Conclusions: Our results show the absence of a significant additional effect of furosemide on calcium levels in patients with severe hypercalcaemia secondary to PHPT when compared with the effect of saline hydration alone. However, zoledronic acid was more potent. Thus, appropriate normal saline hydration with immediate intravenous bisphosphonates infusion should be considered in the management of severe hypercalcaemia in patients with PHPT.