Adjunctive therapy for calciphylaxis progressing despite sodium thiosulfate
A 56-year-old man on hemodialysis for 1.5 years with type 2 diabetes, hypertension, and atrial fibrillation is diagnosed with calciphylaxis of both calves. His medications include apixaban, fosinopril, insulin, and sevelamer. Calcitriol is stopped and sodium thiosulfate is started three times weekly with dialysis, but his pain worsens and the lesions ulcerate into large stellate plaques with thick black eschar, without surrounding erythema or purulence. Calcium 8.9 mg/dL, phosphorus 4.7 mg/dL, albumin 3.2 g/dL, intact PTH 132 pg/mL (dialysis target 130–585), 25-hydroxyvitamin D 18 ng/mL, Kt/V 1.7. What is the most appropriate next step in management?