A 67-year-old woman is evaluated for painful skin lesions that have developed over the past 1-2 weeks. She has longstanding end-stage renal disease, due to diabetic nephropathy, for which she undergoes hemodialysis 3 times a week. Temperature is 37 C (98.6 F), blood pressure is 159/79 mm Hg, pulse is 97/min, and respirations are 16/min. Skin examination findings are shown in the exhibit. Laboratory results show elevated blood urea nitrogen, elevated serum creatinine, and normal serum calcium. Punch biopsy of a lesion shows calcification of the middle layer of the arterioles, subintimal fibrosis, and thrombotic occlusion without vasculitis. Which of the following is associated with an increased risk for the painful skin lesions seen in this patient?

Question

A 67-year-old woman is evaluated for painful skin lesions that have developed over the past 1-2 weeks.  She has longstanding end-stage renal disease, due to diabetic nephropathy, for which she undergoes hemodialysis 3 times a week.  Temperature is 37 C (98.6 F), blood pressure is 159/79 mm Hg, pulse is 97/min, and respirations are 16/min.  Skin examination findings are shown in the exhibit.  Laboratory results show elevated blood urea nitrogen, elevated serum creatinine, and normal serum calcium.  Punch biopsy of a lesion shows calcification of the middle layer of the arterioles, subintimal fibrosis, and thrombotic occlusion without vasculitis.  Which of the following is associated with an increased risk for the painful skin lesions seen in this patient?

Quizplus · Accepted Answer

11ec25c8_d4d6_8c9b_bc81_2d4d5dadc6f5_MD0003_00 This patient has calciphylaxis (also known as calcific uremic arteriolopathy), which is characterized by systemic arteriolar calcification and soft-tissue calcium deposition with local ischemia and necrosis. It occurs most commonly in patients with longstanding end-stage renal disease who are on hemodialysis, or in those with kidney transplants. Calciphylaxis presents with painful subcutaneous plaques and nodules that can be violaceous or purpuric. The nodules can progress to ischemic or necrotic ulcers, become infected, and lead to sepsis; mortality is high. Calciphylaxis is most common in areas of adiposity (eg, trunk, thighs) and, in contrast to atherosclerotic ischemia, usually presents with intact peripheral pulses. Laboratory studies can show high serum parathyroid hormone and hyperphosphatemia. Hypercalcemia and an elevated calcium-phosphate product also increase the risk, although normal serum calcium levels do not rule out calciphylaxis because tissue calcium concentrations may be much higher due to local inflammatory changes (Choice C). (Choice A) Magnesium inhibits extraosseous calcification. The risk of calciphylaxis appears to be increased in patients with hypomagnesemia and decreased in those with hypermagnesemia. (Choice D) Obesity and diabetes mellitus increase the risk for calciphylaxis. Patients with end-stage renal disease may develop frequent hypoglycemia due to decreased clearance of insulin, but hypoglycemia does not promote calciphylaxis. (Choice E) Patients with vitamin K deficiency or who are taking vitamin K inhibitors (eg, warfarin) are at increased risk because vitamin K promotes synthesis of matrix proteins that prevent vascular calcification. Educational objective: Calciphylaxis (calcific uremic arteriolopathy) is characterized by systemic arteriolar calcification and soft-tissue calcium deposition with local ischemia and necrosis. It is primarily seen in patients with longstanding end-stage renal disease. Risk factors include hyperparathyroidism, hyperphosphatemia, and hypercalcemia, although serum calcium is often normal. References: Calcific uremic arteriolopathy in end stage renal disease: pathophysiology and management. (http://www.ncbi.nlm.nih.gov/pubmed/25249804)

A 67-Year-Old Woman Is Evaluated for Painful Skin Lesions That