Atypical Calciphylaxis Following Parathyroidectomy and Persistent Severe Hypocalcemia in a Hemodialysis Patient: A Case Report.

Calcific uremic arteriolopathy (CUA) or calciphylaxis is a rare disorder involving painful necrosis of the skin secondary to calcification and thrombosis of small arterioles in patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD). Such events may even occur after parathyroidectomy (PTX), typically in the setting of adynamic bone disease and very low post-PTX parathyroid hormone (PTH) levels. In this report, we describe a 40-year-old woman with ESRD from IgA nephropathy who developed diffuse, painful subcutaneous calcifications that progressed gradually over several weeks, about 10 months after PTX for severe secondary hyperparathyroidism, evolving into a spontaneous ulceration on the left lateral thigh. Pre-PTX, she had a PTH value of 1389.6 pg/mL, but serum corrected calcium was only 7.3 mg/dL. Her postoperative course was complicated by worsening hypocalcemia, a prolonged need for intravenous calcium infusion after PTX consistent with hungry bone syndrome, and ongoing hyperphosphatemia with phosphorus persistently ranging from 6 to 8 mg/dL. Hungry bone-associated hypocalcemia typically requires weeks to months to stabilize, as was the case with this patient, and supplementation is generally titrated to maintain calcium in the low-normal range while avoiding excessive calcium loading. This patient continues to have chronic pain and poor wound healing despite numerous therapies. This case is intended to show the paradox of calciphylaxis in low PTH states and demonstrate the complex interplay of suppressed bone turnover and calcium dysregulation.