Topical Sodium Thiosulfate for the Treatment of Calciphylaxis: Case Report

Calciphylaxis is a rare syndrome of microvascular calcification and skin infarction, occurring most commonly in patients with kidney failure. Calciphylaxis carries a poor prognosis, and current treatment involves mitigating risk factors, wound care, and medical therapies such as intravenous sodium thiosulfate for calcium chelation. We present an innovative treatment approach of topical sodium thiosulfate soaked gauze successfully used to treat calciphylaxis of a 58-year-old female with renal transplant. She presented with a tender bruise over the posterior right calf, in the context of good graft function (serum creatinine 88 μmol/L), warfarin use for metallic mitral valve, and total parathyroidectomy. Ultrasound imaging highlighted extensive subcutaneous tissue calcification. A punch biopsy of the lesion confirmed calciphylaxis and revealed acute deep ulceration within necrotic debris and calcium deposits along dermal blood vessels. She was managed with cessation of calcitriol and warfarin (switch to enoxaparin with anti-factor Xa level monitoring), replacement of vitamin K2, analgesia, and diligent wound care and debridement. She had twice-weekly intravenous sodium thiosulfate without any improvement and was suspended at 16 weeks after developing central line bacteraemia. On routine deep tissue debridement, small hard calcium deposits resembling calcinosis were noted to superficialise. The decision was made to commence thrice-weekly applications of topical sodium thiosulfate, prepared as gauze soaked in sodium thiosulfate 25% 15 mL applied for approximately 15 min. The ulcer completely healed, pain resolved, and topical treatment was suspended after a total of 20 weeks. This case demonstrates successful treatment of calciphylaxis using topical gauze soaked in sodium thiosulfate without concurrent intravenous sodium thiosulfate.