Hypocalcemia After the Administration of Denosumab in a Patient With Osteoporotic Fracture and Vitamin D Deficiency

Abstract

Denosumab is a potent antiresorptive agent used for the treatment of osteoporosis and the prevention of skeletal-related events in patients with multiple myeloma or bone metastasis from solid tumors. Although denosumab generally seems to be safe and well tolerated, denosumab-associated hypocalcemia may occur, and the majority of cases are asymptomatic or mild. Underlying malignancy, renal failure, calcium or vitamin D deficiency, and high bone turnover have been reported as risk factors for hypocalcemia. Here, the author reports a case of hypocalcemia and hypophosphatemia following the administration of denosumab for the treatment of osteoporotic fracture in a patient with underlying but unrecognized severe vitamin D deficiency. Following the supplementation of calcium, vitamin D, and phosphorus, serum calcium and phosphorus levels returned to normal levels after about 2 weeks. To avoid denosumab-associated hypocalcemia, calcium and vitamin D status, as well as renal function should be assessed and corrected if appropriate.

Refractory Shock Secondary to Denosumab-induced Severe Hypocalcaemia

“…Denosumab is a fully human monoclonal antibody against RANKL which prevents it from binding to RANK receptors on the osteoclast surface, decreasing bone resorption and increasing bone mass [ 1 ] . Hypocalcaemia is a common side-effect of denosumab, reported in around 2% of patients in clinical trials but up to 40% in the literature post-marketing [ 2 , 3 ] . It usually develops 7–14 days following administration.…”

Diagnostic and Therapeutic Approach to Hypercalcemia: A Mini-Review and Discussion of Cases

“…Vitamin D levels should be checked, and severe deficiencies should be treated prior to commencement of denosumab. Patients with low baseline vitamin D can become hypocalcemic following administration of denosumab [19].…”