PSAT194 Prolonged Hypercalcemia after Calcium Sulfate Beads Use

Calcium sulfate beads (CSB) preparations are used for antibiotic release to prevent or treat periprosthetic infections. Transient hypercalcemia in the setting of CSB use have been reported, with most cases being mild. Here we present a case of prolonged hypercalcemia after the use of CSB A 92-year old man with history of CKD stage is admitted to the hospital after sustaining a fall. He underwent a right femur periprosthetic fracture repair. Intraoperatively, he received 30 cc of antibiotic impregnated calcium sulfate beads into the wound. Preoperative labs showed calcium of 9.8 mg/dl, albumin 3.6g/dL, with creatinine of 1.6 mg/dl. 48-hours post-operative, patient developed acute encephalopathy, with laboratory analysis showing a calcium corrected for albumin raising up to 13.2 mg/dL, and creatinine of 1.8 mg/dl in the following days. PTH levels, PTH-rp, 25-OH Vitamin D were normal. He had no history of calcium disorders, kidney stones or pathological fractures. He was started on gentle IV fluids with normal saline, and calcitonin weight based (4 iu/kg) every 12 hours for a total of 6 doses with no improvement of calcium levels. Since he continued with persistent hypercalcemia, we decided to give 1 dose of Zoledronic Acid IV. Patient mental status improved; and calcium levels normalized along with creatinine 11 days after Zoledronic acid. Hypercalcemia secondary to CSB is rare. The use of CSB implantation has increased by orthopedics in the last years. CSB releases 100% of its antibiotic load to improve antibiotic delivery for prevention and treatment of peri-prosthetic infections. There are only two studies evaluating the outcomes of CSB that reported hypercalcemia. In a prospective observational study involving 755 patients receiving CSB implantation, only 5.7% developed mild hypercalcemia, and 2 of them were symptomatic, requiring IV fluids and 1 dose of Bisphosphonates. Hypercalcemia can appear 1 day post-operatively and improve after 5 days. Infrequently, hypercalcemia can be moderate to severe causing symptoms as in our patient. It is important to keep in mind transient hypercalcemia with the use of CSB, especially in high-risk patients. Discussion should include alternate options to prevent peri-prosthetic infections and closer monitoring of calcium and creatinine within the first 24-48 hours of implantation. To our knowledge, this is the second case report of prolonged moderate to severe hypercalcemia. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.