EXPLANATION
Answer is B. patient has refractory tertiary hyperparathyroidism due to severe, persistent, elevation of serum parathyroid hormone (PTH) that is refractory to medical therapy. Severe cases may result in pathologic bone fractures, vascular calcification, or refractory anemia. Achilles’ tendon rupture is a rare complication of severe tertiary hyperparathyroidism in patients on dialysis. The mechanism is thought to be due to severe bone resorption at the site of tendon insertion. Tertiary hyperparathyroidism develops after prolonged parathyroid stimulation from chronic hypocalcemia, calcitriol deficiency, and severe hyperphosphatemia. These stimuli increase PTH synthesis and parathyroid cell proliferation. Transformed parathyroid cells have an autonomous secretion of PTH that is not responsive to the plasma calcium concentration. Parathyroid cells do not respond to the normal PTH-suppressive stimuli due to reduced expression of the extracellular calcium-sensing receptor (making Sensipar ineffective) lower-density of the vitamin D receptor (making zemplar ineffective) , and decreased expression of klotho and fibroblast growth factor receptor 1. Tertiary hyperparathyroidism is associated with hypercalcemia and symptoms and signs of high bone turnover (increased alkaline phosphatase). Indications for parathyroidectomy include in a setting of refractory tertiary hyperparathyroidism are Hypercalcemia, refractory hyperphosphatemia, Bone pain and/or fractures; severe, unexplained muscle weakness; or pruritus, Calciphylaxis (calcific uremic arteriolopathy), PTH >1000 pg/mL that is refractory to medical therapies even though the patient has no obvious associated clinical symptoms
Reference
1)van der Plas WY, Noltes ME, van Ginhoven TM, Kruijff S. Secondary and Tertiary Hyperparathyroidism: A Narrative Review. Scand J Surg 2020; 109:271.
2) Parfrey PS, Chertow GM, Block GA, et al. The clinical course of treated hyperparathyroidism among patients receiving hemodialysis and the effect of cinacalcet: the EVOLVE trial. J Clin Endocrinol Metab 2013; 98:4834.
3) Jones N, Kjellstrand CM. Spontaneous tendon ruptures in patients on chronic dialysis. Am J Kidney Dis 1996; 28:861.
