Prolonged Hypercalcemia from Antibiotic-Eluting Calcium Sulfate Beads

Objective: Calcium sulfate beads (CSBs) are biocompatible hydrophilic crystals that are used to deliver local antibiotics in periprosthetic joint infections. Hypercalcemia after placement of CSBs is uncommon and poorly understood. Methods: We present the case of a woman who presented with symptomatic hypercalcemia after placement of antibiotic-eluting CSBs. Results: A 58-year-old, Caucasian woman presented with altered mental status, respiratory failure, and septic shock 2 days after placement of antibiotic-eluting CSBs for a left prosthetic hip infection. Laboratory analysis revealed severe hypercalcemia at presentation. She had no known history of fractures, kidney stones, parathyroid, or calcium disorders. She was not on any medications that could induce hypercalcemia. She was treated with aggressive intravenous hydration and 8 doses of calcitonin. Due to impaired renal function, bisphosphonate was contraindicated. She subsequently became anuric with worsening renal failure and volume overload and the decision was made to initiate dialysis. She received 8 days of continuous renal replacement therapy followed by 2 sessions of hemodialysis which improved her serum calcium levels, mental status, and renal failure with no long-term complications. Conclusion: Hypercalcemia secondary to the placement of antibiotic-eluting CSBs is rare. Larger volumes of CSBs may contribute to hypercalcemia. In some cases, hypercalcemia can be severe and symptomatic as in the case of our patient. Serum calcium levels should be monitored frequently after placement of CSBs and managed as appropriate.