Severe hypocalcemia after treatment with zoledronic acid : a case report

Abstract

Intravenous bisphosphonates are widely used to treat bone metastasis and myeloma patients. Although symptomatic hypocalcaemia is a potential risk of these treatments, thought to be uncommon. We report a patient with multiple myeloma who developed symptomatic hypocalcaemia after treatment with zoledronic acid. We report a case of a 58-year-old female with a history of inflammatory back pain since two years. Skeletal x-ray examination revealed diffuse and important lytic lesions. Investigations revealed a functional renal failure with hypercalcemia and hypoglobulinemia. Diagnosis of chain multiple myeloma was made. The calcium seric level and kidney function were normalized by an intensive hydration and furosemide injection. The patient started chemotherapy, intravenous bisphosphonate and proposed for marrow transplantation. However, 6 days after the first infusion of Zoledronic acid the patient developed symptomatic and severe hypocalcemia (1, 32 mmol / l). The hypocalcaemia was refractory to intravenous calcium supplementation and needed 15 days before to be stabilized. The risk of hypocalcaemia is a rare but underestimated side effect of zoledronic acid infusion. The authors will try to explain the causes of severe hypocalcemia at present observation while recalling the different mechanisms reported.