Risk factors for severe hypocalcemia after subtotal parathyroidectomy include Severe preoperative hypercalcemia Removal of a large adenoma Elevated alkaline phosphatase Evidence of osteitis fibrosa cystica on bone x-rays Chronic kidney disease Idiopathic hypoparathyroidism is an uncommon sporadic or inherited condition in which the parathyroid glands are absent or atrophied.