PROLONGED HYPERCALCEMIA FROM ANTIBIOTIC-ELUTING CALCIUM SULFATE BEADS

Limitations and modifications in the clinical application of calcium sulfate

Calcium sulfate and calcium sulfate-based biomaterials have been widely used in non-load-bearing bone defects for hundreds of years due to their superior biocompatibility, biodegradability, and non-toxicity. However, lower compressive strength and rapid degradation rate are the main limitations in clinical applications. Excessive absorption causes a sharp increase in sulfate ion and calcium ion concentrations around the bone defect site, resulting in delayed wound healing and hypercalcemia. In addition, the space between calcium sulfate and the host bone, resulting from excessively rapid absorption, has adverse effects on bone healing or fusion techniques. This issue has been recognized and addressed. The lack of sufficient mechanical strength makes it challenging to use calcium sulfate and calcium sulfate-based biomaterials in load-bearing areas. To overcome these defects, the introduction of various inorganic additives, such as calcium carbonate, calcium phosphate, and calcium silicate, into calcium sulfate is an effective measure. Inorganic materials with different physical and chemical properties can greatly improve the properties of calcium sulfate composites. For example, the hydrolysis products of calcium carbonate are alkaline substances that can buffer the acidic environment caused by the degradation of calcium sulfate; calcium phosphate has poor degradation, which can effectively avoid the excessive absorption of calcium sulfate; and calcium silicate can promote the compressive strength and stimulate new bone formation. The purpose of this review is to review the poor properties of calcium sulfate and its complications in clinical application and to explore the effect of various inorganic additives on the physicochemical properties and biological properties of calcium sulfate.

Hypercalcemia Secondary to Antibiotic-Eluting Calcium Sulfate Beads

The use of calcium sulfate beads (CSBs) as a carrier for local delivery of antibiotics is increasingly reported for the treatment of localized infections. They are used most commonly in bone and joint infections, post-trauma infections, diabetes-related foot wounds, and vascular grafts. Hypercalcemia is rarely reported with CSB use but is an important safety concern, and patients at higher risk should be identified prospectively and followed carefully postoperatively. This case report details an 85-year-old male who developed severe, symptomatic postoperative hypercalcemia after antibiotic bead placement in the right knee. He presented with confusion, weakness, and lethargy, and was subsequently treated with fluids, calcitonin, and alendronate. The patient quickly returned to normal mental status, and calcium levels normalized, leading to discharge. The case report and review of the literature describe an incident of severe hypercalcemia attributed to the use of antibiotic-eluting CSBs and describe the risk factors and time course that may be expected.

Hypercalcaemia caused by calcium sulfate beads

Hypercalcaemia is a relatively common metabolic disturbance seen in hospitalised patients; however, given the complicated systems of calcium regulation, it can take a significant amount of time and testing to pinpoint the aetiology. This case discusses a patient who developed acute hypercalcaemia from calcium sulfate-containing antibiotic beads placed during an orthopaedic procedure. These beads are used in surgical procedures to fill gaps/voids in bony structures and for local delivery of antibiotics. The case highlights the importance of careful review of a patient's hospital course, including the administration of medical products that may not be clearly documented on a patient's medicine administration record when working up an unexplained finding.

Hypercalcemia in a 67-Year-Old Female Following the Use of Calcium Sulfate Beads: A Case Report and Review of Literature

While the milk-alkali syndrome is traditionally viewed as the sole cause of exogenous hypercalcemia, the wide use of calcium sulfate (CS) in orthopedic procedures introduced another important item to be considered in the differential diagnosis. Calcium sulfate beads are increasingly used as void fillers and prophylactic measures to prevent postoperative hardware infections. However, hypercalcemia secondary to rapid calcium absorption from calcium sulfate beads is generally an underrecognized adverse effect and likely underreported. Furthermore, with calcium sulfate beads, hypercalcemia can dramatically present with alteration in mental status. In this report, we present a case of a 67-year-old female who underwent two orthopedic procedures, where calcium sulfate beads were used in both. The patient, on both occasions, developed significant hypercalcemia, manifested as agitation and suicidal thoughts, with each episode resolving after proper hydration and lowering of serum calcium. Also, in this report, we examined the literature and highlighted the female predominance in the reported cases, often manifesting in postoperative day (POD) 4. Given the acuity and severity of hypercalcemia, it is paramount to anticipate hypercalcemia, monitor serum calcium postoperatively to allow timely interventions, and avoid potentially serious complications.

Rare Causes of Hypercalcemia

This article discusses rare causes of hypercalcemia. Hypercalcemia can rarely be associated with immobilization, genetic diseases in children such as Williams-Beuren syndrome, Hypophosphatasia, Jansen Metaphyseal Chondrodysplasia (JMC), cosmetic injection, milk-alkali syndrome (MAS), calcium sulfate beads administration, manganese intoxication, postacute kidney failure recovery, and Paget's disease.

The Risk of Iatrogenic Hypercalcemia in Patients Undergoing Calcium Sulphate Beads Implantation in Prosthetic Joint Surgery: A Systematic Review

Calcium sulphate beads are increasingly being used in the management of prosthetic joint infections (PJI). Traditionally their use was limited to a void or dead space-filling combined with other additives such as Hydroxyapatite. Over the last decade, they have been developed to act more frequently as an antibiotics delivery system. Stimulan, a bio-absorbable form of Calcium sulfate, theoretically has an increased risk of hypercalcemia. Over the last few years, there have been published case reports which report it as an isolated cause of iatrogenic hypercalcemia. The sparsity of literature on this topic makes it difficult for surgeons to decide on the use of Calcium sulphate beads in patients with hypercalcemia predisposition in conditions like autoimmune disorders, sarcoidosis, malignancy, granulomatous diseases, heterotopic ossification, and hyperparathyroidism. The study was performed to assess the risk of hypercalcemia in patients after Calcium sulphate beads implantation in PJI. Two reviewers searched relevant literature in 3 online databases using cochrane methodology for systematic reviews. Studies reporting complications with the use of calcium sulphate beads in prosthetic joints were included. Studies reporting on less than five patients and studies reporting use in any other surgeries were excluded. The search of databases resulted in a total of 96 articles. After screening, a total of four articles were deemed suitable to be included in the analysis. A total of 1049 patients underwent calcium sulfate beads implantation, out of which 44 (4.2%) reported hypercalcemia with 41 (3.91%) transient in nature and 3 (0.28%) required management, including one with ICU admission. The result of this systematic review shows that calcium sulphate beads are safe and effective against PJI. There is a significant risk of transient hypercalcemia in susceptible patients and a low risk of symptomatic hypercalcemia.

Analyzing scaling behavior of calcium sulfate in membrane distillation via optical coherence tomography

Deepening the understanding of scaling processes would facilitate the improvement of membrane distillation (MD) as a promising technique for sustainable development. This study investigated the scaling of calcium sulfate in MD via an approach based on optical coherence tomography (OCT). The OCT-based characterization enabled an analysis that correlated the flux decline with the morphological evolution of the scaling layer. It was revealed by this analysis that the reduction in the evaporation rate could be dominated by different mechanisms as the crystalline particles grew and deposited on the membrane surface; the striping phenomenon visualized by mapping the local growth rates provided evidence for the hydrodynamic instability induced by the coupled mass and heat transfer in MD. Moreover, the OCT-based characterization was exploited to unravel the interplay between the crystallization and the porous structure by quantifying the membrane deformation as a function of time; the varied precipitation kinetics in the boundary layer was confirmed by comparing the temporal variations in the OCT signals at different depths. All these results shed light on mechanisms underlying complex scaling processes, which are the basis for optimizing the design of MD.

Unique case of profound iatrogenic hypercalcemia in a patient with recent orthopedic prosthetic infection

Hypercalcemia is a common electrolyte disorder and is typically caused by parathyroid-dependent and parathyroid-independent causes. The most common parathyroid-independent causes include malignancy, granulomatous diseases, over-supplementation with calcium, and hypervitaminosis D. We present an unusual case of a woman who had Stimulan implanted after an artificial knee joint infection. When a washout was done, the patient’s serum calcium started rising, peaking at an astounding 21.2 mg/dL (normal range 8.4 – 10.2 mg/dL) with acute kidney injury. After aggressive hydration and treatment with furosemide, bisphosphonates, and calcitonin, the serum calcium dropped to 10.1 mg/dL. A full hypercalcemia workup did not reveal an alternate cause. On further investigation, it was found that Stimulan is calcium based, and the agitation of these beads during washout was hypothesized to result in the observed profound hypercalcemia.