An Unfortunate Case of Nonuremic Calciphylaxis

Learning Objective #1: Recognize and distinguish calciphylaxis from other forms of ulcerating vasculitides in nonuremic patients. CASE: A 74-year-old female smoker with a history of diabetes and peripheral artery disease (PAD) presents with painful persistent ulcers on her left arm and bilateral legs. She had a similar presentation one year ago and was diagnosed with thromboangiitis obliterans (Buerger\u27s disease) after a biopsy of the leg ulcer showed inflammatory intraluminal thrombus. At that time, the patient was treated with antibiotics and counseled on smoking cessation. She successfully quit smoking, however skin ulcers continued to progress, which is unusual in Buerger\u27s disease. She returned one year later with painful necrotic skin lesions involving the proximal legs, feet, and arms. Extensive rheumatological, hematological, endocrinological, vascular and genetic testing were all negative. A repeat punch biopsy was performed and revealed calcification and thrombosis of arterioles in the dermis and subcutaneous adipose tissue. Given extensive necrosis, she required bilateral transmetacarpal amputations. IMPACT/DISCUSSION: We present a rare case of extensive non-uremic calciphylaxis in a patient with normal renal function. Calciphylaxis is an ischemic skin disorder recognized in patients with end-stage renal disease (ESRD). Our patient\u27s history of heavy smoking, diabetes, and PAD gave suspicion to Buerger\u27s disease, diabetic foot ulcerations, or ischemic ulcerations. It is essential to make the proper diagnosis, as treatment varies. The ulcers in Buerger\u27s disease normally involve the distal legs and feet, whereas those in calciphylaxis involve the proximal extremities. Histologically, Buerger\u27s disease has an intraluminal thrombus with relative sparing of the vessel wall and internal elastic lamina. This contrasts with calciphylaxis, which has thrombotic occlusion with dermal arteriolar calcification and subintimal fibrosis. Although rare, a systematic review revealed 36 reported cases of nonuremic calciphylaxis. The exact incidence of the disease is unknown. The only available treatment for calciphylaxis is sodium thiosulfate, but this is ineffective in patients with normal kidney function because it gets cleared by the kidneys too quickly to have any effect. Conclusion: Calciphylaxis is a potentially lethal disorder that carries high morbidity and mortality if not recognized early. Although it is most commonly seen in patients with ESRD, clinical suspicion in non-uremic patients with the appropriate lesion distribution and histological findings is essential to early treatment. Further clinical research is needed to better understand non-renal etiologies and treatment