Systemic Amyloid Presenting with Rapidly Worsening Hyperparathyroidism in Patients with ESKD

Introduction: Hypercalcemia in ESKD patients is commonly associated with tertiary hyperparathyroidism and can be challenging to manage. We report a case of unusually severe PTH-mediated symptomatic hypercalcemia in a hemodialysis patient though to be secondary to rapidly deteriorating hyperparathyroidism. She failed medical therapy and underwent parathyroidectomy. Subsequent histology shows presence of amyloid deposit in the parathyroid specimen. Our case is unusual for rapidly worsening hypercalcemia and hyperparathyroidism and histology finding of amyloid deposit in the parathyroid specimen. We postulated the worsening of hyperparathyroidism and hypercalcemia was related to the amyloid infiltrate in the parathyroid gland Case Description: A 67-year-old woman with background history of ESKD on hemodialysis who has stable hyperparathyroidism from CKD-MBD on medical therapy. She presented with two-week history of gradual functional decline and symptomatic hypercalcemia. Corrected serum calcium was markedly elevated at 3.62mmol/L, with raised iPTH at 117pmol/L. This is significantly higher than her results just 1 month prior to presentation. Ultrasound showed a well-defined 29 x 22 x 12mm hyperechoic nodule posterior to the right thyroid lower pole, consistent with a parathyroid adenoma which was congruent with a region of increased sestamibi tracer uptake with delayed tracer washout on parathyroid scintigraphy. Despite treatment with repeated sessions of hemodialysis, maximal doses of cinacalcet, calcitonin and anti-resorptives, her calcium levels remained high. She underwent parathyroidectomy with expected response in iPTH levels and improvement of hypercalcemia. Histology subsequently reviewed congo red deposit within intertrabecullar, perifollicular and paracortical stroma of parathyroid, thyroid and lymph node tissue. Discussion: Unexplained rapidly worsening hypercalcemia in secondary hyperparathhyroidsm should prompt clinician to investigate for alternative cause of hypercalcemia and systemic amyloid may present with severe hypercalcemia and hyperparathyroidism