Calciphylaxis is a rare and serious disorder characterized by systemic medial calcification of the arterioles that leads to ischemia and subcutaneous necrosis. Histologic inspection may reveal small vessel mural calcification with or without endovascular fibrosis, extravascular calcification (amorphous luminal calcium), and thrombotic vaso-occlusion (leading to ischemic skin necrosis) [1,2].
Calciphylaxis is one of several types of extra-osseous calcification (which also includes intimal, medial, and valvular calcifications) that may occur in patients with end-stage renal disease (ESRD). Traditionally, it has been classified as metastatic calcification, indicating passive mineralization of serum calcium and phosphate crystals.
Calciphylaxis most commonly occurs in patients with ESRD who are on hemodialysis or who have recently received a renal transplant [1-5], but may also occur in non-ESRD patients .
The term "calciphylaxis" is a misnomer since it implies a systemic anaphylactic reaction that was first observed in an animal model . Calcific uremic arteriolopathy (CUA) is more descriptive of this process in ESRD patients; however, calciphylaxis is still widely used to describe this disorder [8,9]. We use the term CUA to refer to calciphylaxis in ESRD patients. We continue to use the term calciphylaxis to refer to the disorder in non-ESRD patients.
Issues related to vascular calcification are presented separately. (See "Vascular calcification in chronic kidney disease" and "Biology of vascular calcification in chronic kidney disease".)