Calciphylaxis from nonuremic causes: a systematic review.

BACKGROUND AND OBJECTIVES Calciphylaxis, or calcific uremic arteriolopathy, is a well-described entity in end-stage kidney disease and renal transplant patients; however, little systematic information is available on calciphylaxis from nonuremic causes. This systematic review was designed to characterize etiologies, clinical features, laboratory abnormalities, and prognosis of nonuremic calciphylaxis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A systematic review of literature for case reports and case series of nonuremic calciphylaxis was performed. Cases included met the operational definition of nonuremic calciphylaxis-histopathologic diagnosis of calciphylaxis in the absence of end-stage kidney disease, renal transplantation, or acute kidney injury requiring renal replacement therapy. RESULTS We found 36 cases (75% women, 63% Caucasian, aged 15 to 82 yr) of nonuremic calciphylaxis. Primary hyperparathyroidism, malignancy, alcoholic liver disease, and connective tissue disease were the most common reported causes. Preceding corticosteroid use was reported for 61% patients. Protein C and S deficiencies were seen in 11% of patients. Skin lesions were morphologically similar to calcific uremic arteriolopathy. Mortality rate was 52%, with sepsis being the leading cause of death. CONCLUSION Calciphylaxis should be considered while evaluating skin lesions in patients with predisposing conditions even in the absence of end-stage kidney disease and renal transplantation. Nonuremic calciphylaxis is reported most often in white women. Mineral abnormalities that are invoked as potential causes in calcific uremic arteriolopathy are often absent, suggesting that heterogeneous mechanisms may contribute to its pathogenesis. Nonuremic calciphylaxis is associated with high mortality, and there is no known effective treatment.