PTH and Hypomagnesemia: The frequency of new bone remodeling sites decreases, and the bone remodeling gap decreases, leading to a rapid, severe or even continuous decline in serum calcium, phosphorus and magnesium, manifesting electrolyte disorders such as secondary hypocalcemia, hypophosphatemia and hypomagnesemia.[15] Secondary hypocalcemia is associated with a secondary elevation of PTH, and hypophosphatemia is more common in postoperative patients with decreased bone resorption and increased bone formation and normal urinary phosphorus excretion.