Calcific uremic arteriolopathy in peritoneal dialysis populations

Abstract

Calciphylaxis or calcific uremic arteriolopathy is an infrequent complication of end stage kidney disease. It is characterized by arteriolar medial calcification, thrombotic cutaneous ischemia, tissue necrosis often leading to ulceration, secondary infection and increased mortality rates. Current, multimodality treatment involves local wound care, well-controlled calcium, phosphate and parathyroid hormone levels and combination therapy with sodium thiosulfate and hyperbaric oxygen therapy. This combination therapy may be changing the historically poor prognosis of calcific uremic arteriolopathy reported in the literature. Peritoneal dialysis is considered a risk factor based on limited publications, however this remains to be proven. Clinical presentation, diagnosis, pathogenesis and treatment of calcific uremic arteriolopathy in these patients are no different from other patients manifesting with this condition.

Figure 1

CUA lesion on the lateral abdominal wall with early ulceration, surrounding erythema and induration.

Figure 2

Large CUA lesion of the proximal lower limb with necrotic ulceration.

Figure 3

Characteristic biopsy specimen of CUA demonstrating circumferential calcification of small blood vessels with narrowing of the vascular lumen.

Figure 4

Schematic representation for the pathogenic mechanisms of CUA development and the potential sites of action for therapeutic intervention, where (+) indicates augmentation and (−) indicated inhibition; STS, sodium thiosulfate; HBO, hyperbaric oxygen; PO₄⁻, phosphate; Ca⁺⁺, calcium; NDPT, sodium-dependent phosphate cotransporter (Pit-1); vSMC, vascular smooth muscle cell; Cbfa-1, core-binding factor alpha 1; NFκB, nuclear factor κ−B; RANK(L), receptor activator of NFκB (ligand); OPG, osteoprotegerin; TNF-α, tumour necrosis factor alpha; IL-1 interleukin 1; BMP, bone morphogenic protein; ESKD, end-stage kidney disease; MGP, matrix G1a protein; ASHG, α-2 Heremans-Schmid glycoprotein.