361 Successful treatment of calciphylaxis related to lupus erythematosus in a non-uremic, euparathyroid state: Case report and discussion

Calciphylaxis, an aggressive and difficult to treat vasculopathy, occurs most commonly in association with end-stage renal disease (ESRD). It rarely occurs in patients without end-stage renal disease (ESRD), referred to as non-uremic calciphylaxis (NUC) in such settings. Herein, we present a case of NUC in a patient with a complex rheumatologic history and discuss the pathophysiologic mechanisms driving NUC development. A 60-year-old woman with systemic lupus erythematosus (SLE), myasthenia gravis (MG), and Sjogren syndrome (SS) was transferred to our hospital for evaluation of longstanding and intensely painful lower extremity wounds. Physical examination revealed large reticular and stellate purpuric plaques on the legs, with focal areas of vesiculation, ulceration, and faint erythema. An expansive and deep surgical defect from prior debridement was present on the right calf. Renal function and hypercoagulability studies were normal. Incisional wedge biopsy revealed concentric calcification of small to medium vessels in concert with pseudoxanthoma elasticum-like fibers, collectively diagnostic of calciphylaxis. Treatment with sodium thiosulfate (STS) 25 mg intravenously 3 days/week resulted in diminished pain. At 16-week follow up, the cutaneous lesions continued to heal with sustained response on STS. Most existing literature on STS for calciphylaxis is in ESRD patients; our case illustrates the efficacy of STS even in cases of NUC. To our knowledge, only two cases of NUC due to SLE have been previously reported. Literature review suggests that vitamin D deficiency-induced compensatory hyperparathyroidism in concert with SLE may promote NUC. While the pathogenesis of NUC is the subject of continued investigation, the apparent success of STS therapy in our patient thus far adds to a handful of existing case reports and may offer hope to other patients with this painful and life-threatening disease.