Endocrine Abstracts

Denosumab is a monoclonal antibody used in the treatment of osteoporosis to prevent bony injuries by increasing bone density. It does so by binding to RANK-L, which is then unable to activate RANK, thereby preventing osteoclast maturation and viability. Although rare, the effect of denosumab can interfere with the body’s calcium homeostasis and lead to a hypocalcemic state. We present a case where a post-menopausal female developed severe, symptomatic hypocalcemia from a multifactorial etiology of a side effect from denosumab and concomitant Vitamin D Deficiency. The patient originally presented to the ED with a chief complaint of intermittent and worsening whole body numbness and confusion per her family members. Her serum calcium level on presentation was 4.3 mg/dl and attempts at improvement were refractory to multiple administrations of intravenous calcium; however, her symptoms and calcium levels improved after receiving continuous intravenous calcium and Vitamin D later during her hospital stay. Importantly, this condition could have been prevented as she was not a candidate for denosumab therapy given the results of her most recent bone scan. This case allows for insight on use of denosumab and which patients are optimal candidates for the drug and who are not, as well as the necessary testing and diagnoses to establish before initiating treatment with the drug.