Severe Hypercalcemia Following the Implantation of Antibiotic Impregnated Calcium Sulfate Beads for Prosthetic Joint infection

Prosthetic joint infections are a significant cause of morbidity and mortality, which affect only a small number of joint replacements annually. Antibiotic impregnated beads are increasingly used to combat these infections. This delivery system is believed to be safe, however, we present a case of a patient who developed severe hypercalcemia several days after implantation of calcium sulfate beads during a revision of an infected total knee athroplasty. A 70-year-old male was admitted to our institution due to infected prosthetic total knee arthroplasty. All of the patient’s pre-operative labs were within normal limits. He was taken for irrigation, debridement and poly exchange of the infected knee by orthopedics. During the procedure, 10 mL of 10 ml of calcium sulfate beads impregnated with Vancomycin and 10 mL of calcium sulfate beads impregnated with Tobramycin was implanted in the knee. Approximately 48-72 hours post-operatively, the patient became more lethargic, confused and had a poor appetite. He was found to be severely hypercalcemic at 14.0 mg/dL An extensive workup for hypercalcemia was unremarkable and the only logical explanation was tbe implanted beads. He was started on aggressive intravenous hydration with IVF and Lasix for volume control with resolution of his symptoms and hypercalcemia. He had no further occurrence of hypercalcemia during follow up period. Hypercalemia is a medical emergency seldomly encountered by internists, but requires acute interventions. This case demonstrates a possible new cause of hypercalcemia in surgical patients, antimicrobial impregnated calcium sulfate beads. Nonetheless, clinicians should be aware of this etiology of hypercalcemia, given the increased utilization of these types of treatments.