Iatrogenic Hypercalcaemia Secondary to Antibiotic-Eluting Absorbable Calcium Sulphate Beads in Orthopaedic Surgery

INTRODUCTION

Calcium-sulphate beads (CSB) are bio-absorbable antibiotic carriers which are used to manage surgical site infections as well as fill dead space.

Iatrogenic hypercalcaemia from using CSB is a rare but potentially serious adverse effect.

METHOD

In this case report, we describe a patient  who developed symptomatic hypercalcaemia secondary to using CSB during a Girdlestone excision arthroplasty.

RESULTS
An 86-year-old woman with a recent hip hemiarthroplasty for hip fracture developed a deep wound infection. Despite debridement and washout and prolonged intravenous antibiotics, her infection worsened.  The orthopaedic consensus was to remove the infected prosthesis with a Girdlestone excision arthroplasty.

Two days post the Girdlestone, she developed decreased consciousness and altered mental status. She was afebrile with normal cardiovascular respiratory and abdominal examinations but a P on the AVPU scale (response only to painful stimuli). Blood tests showed severe hypercalcaemia (corrected calcium-3.34mmol/L).

She had no past medical history of parathyroid or calcium disorders. Her previous calcium results before Girdlestone were within normal limits. She was taking Alendronic acid and calcium/vitamin D supplements for treatment of osteoporosis following her initial hip fracture.

During her operation, “Stimulan” (calcium sulphate beads) impregnated with antibiotics had been inserted (see post-operative X-ray below). Following discussions between orthogeriatric medicine and orthopaedic teams, she was treated with intravenous fluids and intravenous zoledronic acid 4mg infusion. Her clinical status improved, and hypercalcaemia resolved over the following week.

A literature review discovered the incidence of hypercalcaemia due to CSB is about 4.2%, with about 3.91% of cases being transient in nature, and 0.28% requiring treatment.(1)

CONCLUSION

This case illustrates the importance of including iatrogenic hypercalcaemia as a differential diagnosis for post-operative patients presenting with altered mental status after the use of CSB(2).

REFERENCE:

1. Tarar, Muhammad Yasir et al. “The Risk of Iatrogenic Hypercalcemia in Patients Undergoing Calcium Sulphate Beads Implantation in Prosthetic Joint Surgery: A Systematic Review.” Cureusvol. 13,10 e18777. 14 Oct. 2021, doi:10.7759/cureus.18777
2. Walker MD, Shane E. Hypercalcemia: A Review. JAMA. 2022;328(16):1624–1636. doi:10.1001/jama.2022.18331