Unexpected Early Hypercalcemia after Parathyroidectomy in a Patient with Tumoral Calcinosis and Severe Calciphylaxis

Introduction: Hypocalcemia due to hungry bone syndrome commonly occurs after total parathyroidectomy (tPTX) in kidney failure patients. This is a paradoxical hypercalcemia case after tPTX in a patient with severe calcific uremic arteriolopathy (CUA) and extensive extraosseous calcium deposits (tumoral calcinosis, TC). Case Description: A 54-year-old woman with kidney failure on hemodialysis for 4 years (2X/week), admitted to the emergency room with fever and severe neuropathic pain in extremities. Physical examination showed huge ischemic ulcers on lower limbs (see figure). Additionally, asymptomatic palpable masses were found in her shoulders, knees and hips. A skin biopsy confirmed the diagnosis of CUA, while a PET-CT scan revealed extensive vascular calcifications and calcium phosphate deposits (CPD) in soft tissues and periarticular areas (TC). Lab tests revealed severe hyperparathyroidism (HPT) with iPTH 2049pg/mL, alkaline phosphatase (ALP) 245U/L, normocalcemia (free calcium 4.5 mg/dL), hyperphosphatemia (6.5 mg/dL) and low vitamin D. She received IV antibiotics, surgical debridement, hemodialysis (HD), calcimimetics and opioids. A tPTX was performed (post-surgery iPTH <50pg/mL). However, she experienced sustained elevations in calcium levels (free calcium >7mg/dL), which required frequent HD for lowering. After tPTX, pain intensity decreased as did ALP, iPTH remained low and ALP levels, yet hypercalcemia persisted. Other causes of hypercalcemia were discarded. Discussion: We present a novel case of early hypercalcemia development post-tPTX in a patient with CUA and extensive CPD. Mobilization of calcium from extraosseus stores and a poor bone resorption (early adynamic bone disease) seem the main cause of early hypercalcemia in this case. While tPTX has proven effective in managing TC and CUA associated with severe HPT, paradoxical hypercalcemia after tPTX may occur early in cases with extensive extraosseouss CPD.Clinical presentation and evolution