Calciphylaxis
Calciphylaxis is a rare, life-threatening syndrome of vascular calcification that most commonly affects patients with end stage renal disease (ESRD). Vascular calcification causes small vessel occlusion in subcutaneous adipose tissue and dermis that eventually results in intensely painful, ischemic skin lesions. Eventually these lesions ulcerate. Prognosis is poor with most patients surviving less than one year after diagnosis. Wound infection progressing to sepsis is the most common cause of death.
Risk factors for calciphylaxis include obesity, diabetes mellitus, female gender, warfarin anticoagulation and dialysis for more than 2 years. Elevations of plasma calcium and phosphate concentrations increase the risk of calciphylaxis in dialysis patients. Overuse of calcium and vitamin D supplements during dialysis lead to PTH suppression and low bone turnover, which may exacerbate calcium deposition in soft tissue.
Skin biopsy is the standard method for confirmation of clinically suspected calciphylaxis, but it could provoke new ulcers and infection. Biopsy is not needed for a patient with ESRD and the classic presentation of a painful necrotic ulcer covered with a black eschar. Biopsy should be strongly considered if a patient has early, atypical lesions or if calciphylaxis is suspected in a patient without ESRD. A biopsy is contraindicated for acral, penile, or infected lesions. Elevations in plasma calcium and phosphate are not specific for calciphylaxis. Many dialysis patients with calciphylaxis have either normal or low levels of calcium and phosphate.
Reference
S.U. Nigwekar, R. Thadhani, and V.M. Brandenburg. Calciphylaxis, N Engl J Med 2018;378:1704-1714
