Nephrogenic Calciphylaxis Arising after Bariatric Surgery: A Case Series.

Nephrogenic calciphylaxis is associated with multiple risk factors including long-term dialysis dependence, hyperphosphatemia, hypercalcemia, parathyroid hormone derangements, vitamin K deficiency, obesity, diabetes mellitus, warfarin use, and female sex. Bariatric surgery is known to cause altered absorption, leading to mineral and hormonal abnormalities in addition to nutritional deficiency. Prior case reports on calciphylaxis development following bariatric surgery have been published, though are limited in number. We report a case series of five bariatric patients from a single institution who developed nephrogenic calciphylaxis between 2012 and 2018. These patients had a history of bariatric surgery, and at the time of calciphylaxis diagnosis, demonstrated laboratory abnormalities associated with surgery including hypercalcemia (n = 3), hyperparathyroidism (n = 2), hypoalbuminemia (n = 5), and vitamin D deficiency (n = 5), in addition to other medication exposures such as vitamin D supplementation (n = 2), calcium supplementation (n = 4), warfarin (n = 2), and intravenous iron (n = 1). Despite the multifactorial etiology of calciphylaxis and the many risk factors present in the subjects of this case series, we submit that bariatric surgery represents an additional potential risk factor for calciphylaxis directly stemming from the adverse impact of malabsorption and overuse of therapeutic supplementation. We draw attention to this phenomenon to encourage early consideration of calciphylaxis in the differential for painful skin lesions arising after bariatric surgery as swift intervention is essential for these high-risk patients.