Is sodium thiosulfate a therapeutic option for nonuremic calciphylaxis?

Introduction: Non­uremic calciphylaxis, a rare disorder with high mortality, is associated with severe calcifications of the media of arterioles which cause vascular occlusion and tissue necrosis. Case Report: A non­uremic calciphylaxis of the lower limb, possibly caused by coumarin therapy for atrial fibrillation. Treatment consisting of coumarin avoidance, vitamin K supplementation and thrice weekly infusion of 20 g of sodium thiosulfate for three weeks led to complete healing of the leg ulcers. Conclusion: Sodium thiosulfate produces a considerable sodium load and may induce a decrease in serum calcium, potassium and phosphate levels as well as an increase in the anion gap. We suggest that sodium thiosulfate is effective in the treatment of non­uremic calciphylaxis, but its use requires monitoring of electrolytes, acid­ base and volume status. Based on previous studies of sodium thiosulfate pharmacokinetics in individuals with normal renal function, which showed rapid excretion by the kidneys, application as a slow infusion over several hours is recommended in order to enhance its efficacy and avoid unwanted side effects.