Evolution of treatment strategies for calciphylaxis

Abstract

Treatment strategies for calciphylaxis are limited by inadequate understanding of its pathophysiology. Mortality reaches 80%, due to progressive skin ischemia, necrosis and infections. In addition to calcium and parathyroid disorders, hypercoagulability can have a role: primary thrombotic disorders as well as secondary, such as proposed warfarin procoagulant effects. Traditional care addresses the calcium-phosphate-PTH axis: minimizing calcium intake, calcimimetics, cautious vitamin D analogs, strict phosphate control, and surgical parathyroidectomy if necessary. Newer approaches focus on extraosseous mineralization: dissolution of calcium deposits, altering osteoprotegerin and NF-κB pathways, and treating macrophage or cytokine-mediated inflammation. Sodium thiosulfate has reported success, and is thought to be due to enhanced calcium solubility and dialysis clearance. Bisphosphonates may have efficacy by lowering bone turnover or a variety of vascular tissue mechanisms. The literature for both agents is very limited, and optimal dosing regimens remain unclear. Patients responsive to a medication will have decreasing pain in days and lesions beginning to heal within approximately 2 weeks. Due to high mortality, early use of combination therapy is advocated, although specific protocols have not been well established. The often dramatic improvements in case-based literature are very encouraging and will hopefully lead to more rigorous studies.