Calciphylaxis in chronic kidney disease

Abstract

Purpose: Calciphylaxis or Calcific Uraemic Arteriolopathy (CUA) is a rare systemic disorder associated with endstage renal disease and carrying a very poor prognosis and high mortality. It is characterized by skin necrosis and gangrene secondary to thrombosis and calcification of dermo-epidermal arterioles. Pathogenetic mechanisms inducing calciphylaxis are for the most part unknown. Methods: We report a case of calciphylaxis in a patient on long-term haemodialysis with severe secondary hyperparathyroidism. Despite therapies for hyperparathyroidism, the injury healed only after parathyroidectomy. Results: Calciphylaxis is an obliterative vasculopathy. The role of severe hyperparathyroidism in the pathogenesis of calciphylaxis is not well understood. A unique feature is the phenotypic differentiation of smooth muscle cells into osteoid-like cells. The vascular smooth muscle cells, exposed to high inorganic phosphate levels, could be transformed into osteoblast-like cells in patients undergoing haemodialysis with a poor control of phosphate intake. Conclusions: The uraemic condition contributes to vascular smooth muscle cell apoptosis and differentiation into bone forming osteoblast-like cells resulting in medial calcification. Nowadays no effective treatments are available for the successful management of calciphylaxis.